Multifunctional MIL-S─CUR@FC nanoparticles: a targeted theranostic agent for magnetic resonance imaging and tumor targeted delivery of curcumin
Sadegh
Dehghani
Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences (TUMS), Iran
author
Maryam
Hosseini
Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
author
Nader
Riahi Alam
Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences (TUMS), Iran
author
Soheila
Haghgoo
Pharmaceutical Department, Food and Drug Laboratory Research Center, Food and Drug Organization (FDO), Ministry of Health, Tehran, Iran
author
Tohid
Mortezazadeh
Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences (TUMS), Iran
author
text
article
2018
eng
Introduction: Noninvasive magnetic resonance imaging (MRI) and targeted drug delivery systems, usually referred to as theranostic agents, are being developed to enable detection, site-specific treatment, and long-term monitoring. Materials and Methods: To elucidate the effects of coating on cellular uptake and biodistribution of nanoparticles (NPs), negatively charged Fe-MIL-88B-NH2 (MIL-S) was developed and loaded by curcumin (CUR). After that, chitosan (CS) was conjugated to folic acid (FA). Then MIL-S─CUR was coated by CS targeted by FA (FC) and partially negatively charged MIL-S─CUR@FC was developed. Results: MIL-S and MIL-S─CUR@FC owned Zeta potentials of -23 and -2 mV, respectively. MTT assay showed MIL-S─CUR@FC could have maximum cell toxicity on cancer cells due to partially negative charge and active targeting. In vivo magnetic resonance imaging (MRI) images suggested that liver uptake was very high for negatively charged MIL-S. The high T2 contrast effect of MIL-S in liver is likely due to active phagocytosis by macrophages (Kupffer cells) in the liver. In contrast, liver uptake was very low, but tumor uptake was very high for MIL-S─CUR@FC showing high dual contrast (T1/T2). The pH-responsive behavior of MIL- S─CUR@FC in tumor tissue made it dual T1 /T2 contrast agent by decomposition of NPs. Conclusion: It could be concluded that coating, active targeting, and reducing the surface charge of MIL-S─CUR@FC reduced the undesirable clearance by the reticuloendothelial system (RES) such as liver. On the other hand, the anti-cancer drug delivery improved more efficiently to the tumor sites and maximized therapeutic efficacy and predictable in vivo properties. Here described a pH sensitive MRI NPs, may serve as a useful theranostic agent for cancer diagnosis and treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
1
1
https://ijmp.mums.ac.ir/article_11843_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11843
Public exposure to natural radiation sources (Ramsar Case Study)
Nasrin
Fathabadi
Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER) Tehran University of Medical Sciences, Tehran, Iran.
National Radiation Protection Department, Iran Nuclear Regulatory Authority, Atomic Energy Organization of Iran, Tehran, Iran
author
Ali Akbar
Salehi
Department of Energy Engineering, Sharif University of Technology, Tehran, Iran
Atomic Energy Organization of Iran, Tehran, Iran
author
Kazem
Naddafi
Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER)
Department of Environmental Health Engineering, School of Public Health Tehran University of Medical Sciences, Tehran, Iran
author
Mohammad Reza
Kardan
Nuclear Science and Technology Research Institute, Tehran, Iran
author
Masud
Yunesian
Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER)
Department of Environmental Health Engineering, School of Public Health Tehran University of Medical Sciences, Tehran, Iran
author
Ramin
Nabizadeh Nodehi
Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER)
Department of Environmental Health Engineering, School of Public Health Tehran University of Medical Sciences, Tehran, Iran
author
Mohammad Reza
Deevband
Department of Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Molood
Gooniband Shooshtari
Department of Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Human beings are naturally exposed to ionizing radiation in any environment. There are two main contributors to radiation exposures from natural sources: cosmic rays, Cosmo genic radionuclides, and radioactive nuclides that originated in the earth's crust. According to the latest data provided by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the estimated worldwide average annual exposure to natural radiation sources is 2.4 mSv, and the most exposures are in the range of 1–13 mSv/a. There are several small areas throughout the world where people are exposed to natural radiation sources that are in excess of those considered "normal background”. However, there are no specific criteria in this regards, these areas are referred to as "High Natural Radiation (HNRA)" areas. Ramsar is one of these areas. The natural radioactivity of Ramsar is mainly due to the presence of Ra-226 along with its daughters. The aim of this study was to determine the internal and external exposures from natural radiation sources in Ramsar, and to estimate the total annual effective dose for the people in Ramsar. Materials and Methods: In this research, the all radiation sources and exposure pathways of people living in Ramsar were investigated. The concentration of 226Ra was measured by alpha spectrometry and radon emanation in different samples including foods and drinking water, and the internal dose was estimated. In addition, the annual effective dose of exposure to gamma rays and the annual effective dose due to inhalation of radon gas were calculated for residents. Results: The mean annual effective dose due to exposure to indoor gamma rays in Ramsar was 0.66 mSv, the range was 0.3 to 48 mSv, the mean annual effective dose due to exposure to outdoor gamma rays was 0.86 mSv, and the minimum was 0.1 mSv. The mean annual effective dose of internal exposure to radon gas was 10.3 mSv and its range was from 0.9 to 232 mSv. The mean annual effective dose due to ingestion of 226Ra was found 10 µSv and its range was 1 to 81 μSv. Conclusion: Based on the results of this study, the public annual effective dose of Ramsar from exposure to natural radiation sources was 1.25 to 281 mSv, with a mean value of 12 mSv. The results of this study show that the mean value (12 mSv) is approximately 5 times greater than the worldwide mean annual exposure to natural radiation sources reported by the UNSCAER (2.4 mSv). The results obtained could be used in determining the reference levels for controlling the exposure of people and in taking preventive measures to reduce the radiation exposure of the residents. In addition, the results of this research could be useful in the study of the effect of radiation on the public health.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
2
2
https://ijmp.mums.ac.ir/article_11844_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11844
Patient absorbed dose comparison in CT and Stereoradiography (EOS) imaging during lower limb torsion evaluation using in-vivo and in-vitro dosimetry methods
Mahdieh
Ghadimi
Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Ali
Parach
Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Fatollah
Bouzarjomehri
Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Reza
Nafisi Moghadam
Department of Orthopedic, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Seyed Mohammad Jalil
Abrisham
Department of Orthopedic, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
text
article
2018
eng
Introduction: Accurate evaluation of femoral and tibial torsion is essential for children or adult with legs deformity, becuse incorrect legs morphogenesis can lead to pathological situation. CT scan is commonly used for the measurement of skeletal bone parameters. But, disability in imaging from standing and sitting posture and absorb dose of patients are deficits of this method. EOS method overcome this dificits. Likewise some paper have reported decrease of EOS dose rather than dose level in CT, this project aim to measure amount of dose reduction and to verify reduction of EOS dose level in compare to CT. Materials and Methods: For EOS and CT invitro dosimetry, a pencil ionization chamber was used. Computed tomography dose index volume (CTDIvol) was mesuered, using this dosimeter and standard tissue equivalent CT phantom. DLP of both imaging methods was compared for acquisition of adult hip. With radiothermoluminescent detectors (TLD) in vivo dosimetry enterans skin dose for 30 patients was measuered, which 15 of them were underwented CT scan and the other were underwented EOS imaging. Results: The reading of dosimeters level and therefor enterans skin doses, in EOS system was significantly lower than CT scan. Patient dose in AP, RT and LT fields of CT scan was respectively 24, 41.5 and 9 times more than EOS. Enterans skin dose in CT scan was 18 times more than EOS on average. Also, in invitro dosimetry CT scan dose was 47 times more than EOS dose. Conclusion: Elimination of scatter radiation and high quantum efficiency of detector lead to minimum dose for an optimum qulity scan with EOS system than CT scan. Stereoradiography imaging modality will impose less doses of CT scan imaging modality in similar imaging views from the lower limbs.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
3
3
https://ijmp.mums.ac.ir/article_11845_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11845
Comparison of entrance skin dose in the hip region in the imaging of the lower extremity by CT scan and EOS
Mahdieh
Ghadimi
Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Ali
Parach
Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Fatollah
Bouzarjomehri
Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Reza
Nafisi-Moghadam
Department of Orthopedic, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Seyed Mohammad Jalil
Abrisham
Department of Orthopedic, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
text
article
2018
eng
Introduction: Increasing in refer to computed tomography (CT-scan) imaging causes to increase in cumulative dose. Stereoradiography (EOS) is an X-ray imaging technology that, by eliminating scattering radiation, reduces patient's absorption dose and improves image quality. Materials and Methods: This cross-sectional study was carried out in a hospital with two different types of imaging apparatus, EOS Biospace Instruments and CT TOSHIBA MDCT Alexion. 15 patients were selected randomly for each Imaging method. Prior to irradiation, three thermoluminescence dosimeters (TLDs) were installed on the target area in three AP, RT and LT views. The 85 kVp and 110 kVp were used for EOS and CT respectively. The TLDs were read and the statistical analysis was performed using one-way ANOVA. Results: The mean reading of TLD dosimeters in EOS imaging of the lower regions with AP, RT and LT views were 57.88 ± 14.73, 19.84 ± 16.5 and 98.98 ± 19.59 (nc) respectively. These values with similar views in CT scan images were 1369.88 ± 585.18, 824.179 ± 35.22 and 785.66 ± 304 nc. According to the results of statistical analysis, the mean reading of TLDs in all EOS imaging views was significantly lower than the CT imaging method for estimating the entrance skin dosing. Conclusion:Stereoradiography imaging modality will impose less doses of CT scan imaging modality in similar imaging views from the lower limbs.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
4
4
https://ijmp.mums.ac.ir/article_11846_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11846
Effect of BTS on the quality of sleep and life of nearby residents
Fateme
Seif
Department of Radiotherapy and Medical Physics, Faculty of Para medicine, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran
author
Mahsa
SHakeri
Department of Technology of Radiology and Radiotherapy, Allied Medical Sciences School, Tehran University of Medical Sciences, Tehran, Iran
author
Mohammad Reza
Bayatiani
Department of Radiotherapy and Medical Physics, Faculty of Para medicine, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran
author
Azadeh
Amraee
Department of Radiotherapy and Medical Physics, Faculty of Para medicine, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Communication between mobile phones and antenna BTS (Base Transceiver station) is carried by electromagnetic waves that have energy, according to their nature. Increasing use of mobile phones because of the proliferation of antennas the concerns about them are proposed in society. In the present study the correlation between distance from the BTS antennas and the quality of sleep and quality of life have been investigated for residents of the surrounding population.
Materials and Methods: For assess the quality of sleep the Pittsburgh Sleep Quality
standard questionnaire was used and for quality of life the SF-12 questionnaire was used
that contains two parameters: Mental Health Composite Scores = MCS and Physical Health
Composite Scores = PCS.
Results: Analysis of the data (810 people, including 411 females and 399 males) showed residents are living at a distance from 50 to 100 meters have the most sleep disturbance and the minimum average MCS score (p<0.05). Inhabitants who are within 100 to 200 meters from the antenna according to the Quality of Life Questionnaire have the fewer average PCS score rather than the other residents.
Conclusion: The present study demonstrates that exposure to electromagnetic waves probably can affect the sleep quality, mental and physical life quality of the residents depended to distance from the BTS. It seems that antennas implant must be set in patterns that have the lowest intensity regarding to beam convergences for all residents.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
5
5
https://ijmp.mums.ac.ir/article_11847_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11847
Designing and developing an in-house CCD based optical CT scanner for gel dosimetry
Mahmoud
Shiri
Medical Physics and Biomedical Engineering Dept., Shahid Beheshti University of Medical sciences, Tehran, Iran
author
Ahmad
Mostaar
Medical Physics and Biomedical Engineering Dept., Shahid Beheshti University of Medical sciences, Tehran, Iran
author
Zahra
Mansouri
Medical Physics and Biomedical Engineering Dept., Shahid Beheshti University of Medical sciences, Tehran, Iran
author
Seyed Mohsen
Sadat-Shahabi
Medical Physics and Biomedical Engineering Dept., Shahid Beheshti University of Medical sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Measurement of the complex 3D radiation dose distribution created with advanced radiotherapy techniques such as IMRT and SRS became very important. Polymer gel dosimetry (PGD) is proposed method to recording this dose distribution. MRI, X-ray CT, ultrasound, spectrophotometry and optical CT scanners can be used for readout of Polymer gel dosimeters. Although MRI is gold standard readout instrument, but it is costly and time- consuming. Optical CT is faster and has very lower cost than other methods. The aim of this work is designing and developing an in-house fast CCD based optical computed tomography scanner to extract the 3D radiation dose distribution that recorded in irradiated PGDs.
Materials and Methods: in this work we used an array of high power LEDs by 650nm wave length as broad beam light source and a CCD camera as large area detector. The image projections of test object that immersed in a water tank and its rotational movement were controlled by a stepper motor was obtained. Image reconstruction carried out in MATLAB environment with the Filtered back projection method.
Results: Reconstructed image quality is very promising. And it is comparable to results of the other works. Contrast to Noise Ratio (CNR) of reconstructed images without any filters in the back projection algorithm was 0.41. Using ramp filter with 0.2 cutoff frequency, gained a 1.1 in CNR and using Butterworth filter with cutoff frequency of 0.3 gained a CNR of 1.3. Increasing cutoff frequency for Butterworth filter will degrade noise properties of reconstructed image and CNR goes down to 0.82, which is comparable with similar works.
Conclusion: Optical CT readout system is considered one of the best options for gel readings. If we can overcome the problems of reconstructed images with light rays, this system can be useful for fast and accurate readout of irradiated polymer gel dosimeters.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
6
6
https://ijmp.mums.ac.ir/article_11848_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11848
Radiation dose of Pediatrics in a general hospital in comparison to a pediatrics hospital
Ahmad
Mohammadbeigi
MSc Student of Medical Physics, Students Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Karim
Khoshgard
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Abbas
Haghparast
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Mohammad Taghi
Eivazi
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Masoud
Rezaei
Medical Physics Research Center, Department of Medical Physics, Mashhad University of Medical Sciences, Mashhad, Iran.
author
text
article
2018
eng
Introduction: Increasing CT scan application increased the cancer risk in pediatrics in recent
decays. Imaging centers approach for diagnosis of disease cause to different radiation dose to patients. Because of rapid pediatrics body growth, the most important challenge to
determining the radiation dose is wide variations of size in different ages. Thus, we used Size- specific dose estimates (SSDE) to achievement more accurate radiation dose assessment. In this study the radiation dose of head examinations of a general hospital (Trauma center of western Iran) is compared to a pediatrics hospital to find which one has a better approach for dose management.
Materials and Methods: We evaluated the total number of 280 CT scans in four age groups (≤1, 2-5, 6-10, 11-15 years. Number of 35 CT scans selected for every age group in both
hospitals, separately. Volume Computed Tomography Dose Index (CTDIV), Dose Length
Product (DLP), default phantom (16 or 32 cm) and age were recorded in prepared sheets
using PACS viewer. Water equivalent diameter (DW) and SSDE calculated using the AAPM
TG-220. Third and first quartile and mean ± SD were acquired using SPSS (SPSS Inc., Chicago,
IL).
Results: Third quartile of SSDE was 19.64, 18.70, 18.49 and 18.13 mGy in general hospital;
13.78, 11.92, 11.94 and 20.77 mGy for pediatrics hospital in age groups of ≤1, 2-5, 6-10, 11-
15 years respectively. Third quartile of DLP was 317.4, 344.7, 344.7 and 344.6 mGy in
general hospital; 128.5, 136.5, 152.5 and 250.8 mGy for pediatrics hospital in age groups of
≤1, 2-5, 6-10, 11-15 years respectively. Third quartile of CTDIV was 18.3 mGy for all age
categories in general hospital; 11.5, 11.5, 11.5, and 21.1mGy for pediatrics hospital in age
groups of ≤1, 2-5, 6-10, 11-15 years respectively.
Conclusion: General hospital gives the higher radiation dose to pediatrics for head scans with
the exception of 11-15 years’ group. Optimizing the protocols according to the patient size is
essential in both hospitals. Finally, pediatric hospital has a better dose management for
pediatrics CT scans.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
7
7
https://ijmp.mums.ac.ir/article_11850_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11850
Fricke Gel Dose Indicators Applicable for Blood Irradiators
Elham
Edalatkhah
Radiation Applications Research School, Nuclear Science and Technology Research Institute, AEOI, Tehran, Iran
author
Peiman
Rezaeian
Radiation Applications Research School, Nuclear Science and Technology Research Institute, AEOI, Tehran, Iran
author
text
article
2018
eng
Introduction: Transfusion of irradiated blood is recommended by the guidelines for cardiosurgery, cancer surgery, severe trauma and congenital immune deficient recipients. To prevent post- transfusion graft-versus-host disease (PT-GVHD), blood cells may be irradiated by gamma rays. The absorbed dose range for blood irradiation is typically 15 to 50 Gy. As the assurance that blood has been properly irradiated plays an important role for patient health, appropriate gamma dosimetry has to be performed. So, Fricke gel dosimeters in a dose range from 10 to 50 Gy were constructed in this study. Using optical absorption of the gel, the absorbed dose can be determined accurately. Furthermore, the gel can be used as a radiation indicator.
Materials and Methods: The gelling agent powder was added to a beaker containing distilled water. It was then boiled until a clear solution was obtained. Ferrous ammonium sulphate solution containing a metal indicator and sulphuric acid was added. The gel was then poured into cuvettes and left for half an hour before irradiation. Irradiation was done by Gammacell- 220 at 10, 20, 30, 40 and 50 Gy. The optical absorption of the gel was specified using a BECKMAN COULTER-DU-800 spectrophotometer.
Results: Frick gel samples present two absorption bands: one at range from 435 to 445 nm, corresponding to Fe2+ ions initially present in the unirradiated gel and other at range from 575 to 585 nm corresponding to Fe3+ ions generated by radiation induced Fe2+ ions oxidation. The first band tends to disappear depending on the absorbed dose as the second band is intensified with increasing dose. Dose response curve clearly indicates linear range of 10 to 50 Gy.
The color change started immediately after irradiating and was fully developed within thirty minutes. The irradiated region is clearly seen as a blue zone against the unirradiated yellow- orange background. As dose increased from 10 to 50 Gy, the color intensity of the samples was enhanced. The color change showed no visible diffusion for at least five days. If care is taken to follow the gel preparation procedure, the color change produced by radiation is quite reproducible with a low variability.
Conclusion: Fricke gel dosimeters have many appealing features. They are tissue equivalent over a large photon energy range, easily prepared in any shape and are readily analyzed by optical techniques after irradiation. These advantages together with dose indication that enable one to probe the radiation dose more quickly shows that Fricke gel dosimetry has a continuing role in clinical applications. We are working on the development of Fricke gel dosimeters by adding specific dopants to increase the dose sensitivity and uniformity of gel preparation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
8
8
https://ijmp.mums.ac.ir/article_11851_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11851
Calculating Contra-Lateral Breast’s Absorption Dose in Different Radiotherapy Methods of Large Breasts Cancer
Sahar
Beyranvand
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Mehdi
Salehi Barough
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Mohammad
Rahgoshay
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: Breast cancer is one of the most common known cancers in women all around the world. It is the most common cause of death in women after lung cancer. Radiotherapy is a method for therapy of cancer in which certain dose of high energy radiations is used to destruct cancer cells. Radiotherapy is designed so that radiation of eartain does to the target area in body is allowed. In this therapy more radiation dose should be used in tumor and the least dose is used in normal tissues. In this design, Contra-lateral breast’s absorption dose in different radiotherapy methods in large breasts is calculated. In large breasts, normal tissues and more sensitive organs exist in the field due to its anatomical structure.
Materials and Methods: Measurement is performed by 3D Aculips therapy design system and EBT3 Gap chromic film and TLD. This plan was an experimental study. 60 time radiations were used by X-Varian linear medical accelerator device with 6MV energy that 30 times were performed by Gap chromic film and 30 times were performed by TLD. All radiations were performed on the phantom due to protective problems. In this work, CT-simulator phantom was used and then, it was transferred into therapy design computer. TLD and Gap chromic film were installed on Contra-lateral breast, and in all radiation steps, 100 manitor unit (Mu) were used.
Results: After calibrating TLD, first, absorbtion does in breast CT scan is calculated by TLD. This dose is 1.6 cGy. We are inevitable to remove this dose. In radiotherapy planing, three methods are studied. In the first method, common two tangents method, results indicate that a part of the contra-lateral breast tissue and internal memolary lymph nodes are in the radiation field, therefore a part of the breast is placed because the breasts are large. In this method, dose maximum is 84.1 cGy. In the second method two photon-radiation field are placed in the medial area and a part of breast is removed and dose used for the breast is 15cGy. In the method of combination of photon and electron, a part of the main breast is removed from the radiation field. The removed area is in internal area, which is covered by electron tangent with internal field. In this method, the maximum dose reachs to 6 cGy. After calculating by radiotherapy planing, we perform exprimental calculation by TLD in certain points. In usual therapy method, a part of the contra-lateral breast is in radiation field, and it receives a full dose. In edge of field-therapy, absorpthion dose is 83.2% of perspective dose. In this method, tivo beside photon fields reach to 14.9% of perspective dose; and two electron and photon fields reach to 6% in another method for calculating absorpthion dose, after calibration of Gap chromic film of absorption dose, three used methods are calculated, and by putting film on contra-lateral breast, dose phantom is evaluated. From performed measurement, dose level in usual method, two photon fields were 84.1% of perspective dose. In method of two photon fields together percentage of the perspective dose was 15.1%, and for photon-electron fields this value was 6.4%.
Conclusion:
With respect to this design, it can be concluded that if two beside photon- electron fields method is used, dose entered into the contra-lateral breast will be significantly reduced. However, in this design, dose for other sensitive organs must be considered
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
9
9
https://ijmp.mums.ac.ir/article_11852_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11852
Calculation the accumulated dose in the heart and its effect on other human organs by using experimental mouse data and the MCNPX code for FDG
Mehrnaz
Rahmanpour
Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Asghar
Haddadi
Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Fatemeh
Bolorinovin
Atomic Energy Organization of Iran, Nuclear Science and Tecnology Research Institute, Alborz Research institutr, Karaj-Iran
author
Mitra
Athari
Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: The use of ionizing radiation in diagnostic medicine is expanding, and considering the fact that the practical dosimeter in a precise way is almost impossible, the Monte Carlo computational methods help researchers, to have coming up the lowest cost and error of the distribution of doses in the patient's body.
Materials and Methods: In this study, after infusion of 7 to 8 MBq of FDG radioisotope to rat, and the maturation of the body of the mouse, the rate of accumulation of this radioactive drug in various organs of the rat body was measured using the HPGe detector and its activity was calculated and generalized to human. the accumulation dose of heart effecting on other organs was calculated by using MCNPX code, assuming that the injectable drug to humans was 185 MBq, was calculated.
Results: accumulation dose of heart effecting on other organs was calculated by using MCNPX code; that the result of calculation reveals that the highest received dose from the heart to the organs, respectively is related to the heart, lung, liver, stomach, rib cage, spleen, kidney, large intestine brain.
Conclusion: Finally, using the MIRD phantom in the MCNPX2.6 computational code, the heart organs in this simulation were determined as the source and the dose rate received by other organs was calculated.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
10
10
https://ijmp.mums.ac.ir/article_11853_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11853
Development of a Phase Space Generator software for Medical Linear Accelerator Applications
Mohammad Taghi
Batiar
Nuclear Engineering Department, Shahid Beheshti University, Tehran, Iran.
author
Mohammad
Mohammadi
Royal Adelaide Hospital, Department of Medical Physics, Adelaide, Australia.
Reza Radiotherapy and Oncology Centre (RROC), Devision of Medical Physics, Mashhad, Iran
author
Marziyeh
Behmadi
Department of Medical Physics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mahdi
Ghorbani
Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Velenjak, Tehran, Iran
author
text
article
2018
eng
Introduction: During the last decades, simulation of radiation therapy treatment conditions in treatment room for studying with more details in comparison with treatment planning system (TPS) is taken into consideration. The most problem with starting these kind of researches is the geometry of Medical linacs and verification of the accelerators. Therefore, researchers tried to produced phase space after constant parameters of linacs (target, primary collimator, flattening filters) before jaws and offering them to the other researchers specially by International atomic energy agency in IAEA or ROOT format. The goal of this study is to write a phase space generator software which can produced phase space for multiple medical linear accelerators in ROOT and IAEA format. These phase space can have been used in Geant4, Gate, EGSnrc and PENELPOE as a source.
Materials and Methods: In the first step, the head of multiple medical linac accelerators like Varian (Novalis TX, Trilogy, Clinac iX, Clinac DX, Clinac 2100 C/D, Clinac 21 EX, Clinac CX, Truebeam), Simens (Primus, Primus pulse, Artiste and ONCOR) and Elekta (Synergy, Compact, SL) in photon and electron mode in the present of wedge and different applicators were simulated and verified with Geant4. For verification of the simulated linac’s heads, the percentage depth doses (PDDs) and Profiles were compared with experimental data. The comparisons were done with Gamma Index code (3%, 3mm) in MATLAB. In the second step, a software was written which can produce phase space in two formats for the simulated heads without accessing the users to the heads geometry. To validate the accuracy and precision of written software results (Phase space files, PDDs and Profiles), the data which were extracted from these software was evaluated with the Geant4 results.
Results: Based on the Gamma Index results in the first step and evaluation of the produce Phase Space files, the software’s results have a good agreement with Geant4 and Experimental data.
Conclusion: In the written software several medical linacs were modeled and the users can produce ROOT and IAEA phase space format after adjust (regulate) the jaws or MLCs in needed positions and use them in different Monte Carlo codes. In this code most of the Varian, Siemens and Elekta models were implemented and the users can select the present of wedge and change its angel and even positioned the different form of shield in the beam line. Furthermore, user can define new accelerator using simple input Like EGS Code. These parameters are the advantages of this software related to the similar softwares like PRIMO.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
11
11
https://ijmp.mums.ac.ir/article_11854_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11854
Multifunctional GQDs-Coated Fe/Bi Nanohybrids for CT/MR Dual Imaging and in vitro Photothermal Therapy
Samireh
Badrigilan
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Department of medical physics, Faculty of Medical, Tabriz University of Medical
author
Behrouz
Shaabani
Department of Inorganic Chemistry, Faculty of Chemistry, Tabriz University, Tabriz, Iran
author
Nahideh
Ghareh aghaji
Department of Radiology, Faculty of Paramedical, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Asghar
Mesbahi
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Department of medical physics, Faculty of Medical, Tabriz University of Medical Sciences, Tabriz, Iran
author
text
article
2018
eng
Introduction: The multipurpose nanocomposites have gained growing biomedical attention as promising nanotheranostics to improve The effectiveness of cancer treatment, which concurrently combine advantages of the therapeutic and diagnostic techniques into one nanosystem. The “all-in on” probes not only help to ablate cancerous tumors, but also allow to optimize and monitoring of treatment. Materials and Methods: iron/bismuth nanohybrid was synthesized in presence of graphene quantum dots for the co-integration of diagnostic and therapeutic functions into a single nanoprobe (referred to as GQDs-Fe/Bi NPs). Then, for further applications, blood compatibility and cytotoxicity, as important tissues, of different concentration of GQDs-Fe/Bi NPs were investigated by hemolysis test and MTT test, respectively. A 1.5 T MRI scanner (Siemens Avanto- Germany) was employed to measure MR contrast ability of GQDs-Fe/Bi NPs with various concentrations of Fe. In additional, the phantom CT images were taken at the various concentrations of the Bi and iodine using a clinical CT scanner (GE HiSpeed) at operating voltages of 80,120 and 140 kVp. The acquired images were analyzed with imageJ software. To study the photothermal performance, the GQDs-Fe/Bi NPs suspension with a series of concentrations of active Bi metal were exposed to a NIR laser (808 nm, 1.7 W ・cm−2) for 10 min. Results: Such theranostic agent not only shows strong near-infrared (NIR) absorbance, but also offers high contrast for X-ray computed tomography (CT) and magnetic resonance (MR) imaging to the imaging-guided NIR laser irradiation deliver and selectively heating of tumor. Fe3O4 component involved in the hybrid showed the good magnetization property (48.59 emu/g) with excellent performance on magnetic resonance imaging and high relaxivity time (62.34 mM−1 s−1). Synergistically, the presence of the Bi component with high atomic number (Z=83) in the GQDs-Fe/Bi nanohybrid offered high- X-ray contrast for CT imaging. Furthermore, thanks to the high photothermal conversion efficiency of 31.88%, co-delivery of GQDs-Fe/Bi NPs and NIR-radiation can effectively kill the cancer cells. Conclusion: the high theranostic performance of GQDs-Fe/Bi NPs can simultaneously use for CT/MR imaging-guided cancer photothermal therapy purposes.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
12
12
https://ijmp.mums.ac.ir/article_11855_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11855
Non-invasive quantification of liver fat content by different Gradient Echo MRI sequences in patients with Non-Alcoholic Fatty Liver Disease (NAFLD)
Mansour
Zabihzadeh
Research Center for Infectious Diseases of Digestive System, &Department of Clinical Oncology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mohammad Momen
Gharibvand
Assistant Professor of Radiology, Department of Radiology, school of medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Azim
Motamedfar
Assistant Professor of Radiology, Department of Radiology, school of medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Amir Hossein
Sina
AP-CP, Narges pathobiology lab technical manager
author
Zahra
Farzanegan
MSc Medical Physics student, Department of medical physics, school of Medicine, Ahvaz Jundishapur University of Medical science, Ahvaz, Iran
author
Mozafar
Naserpour
PhD student, Instructor of radiology technology, Behbahan Faculty of Medical Sciences, Behbahan, Iran
author
text
article
2018
eng
Introduction: Non-invasive quantification of liver fat by Gradient echo (GRE) Technique is an interesting issue in quantitative MRI. Despite the numerous advantages of this technique, fat measurement maybe biased by confounding and effects. The aim of this study was to evaluate the GRE pulse sequences with different and weighting for liver fat quantification in patients with Non-Alcoholic Fatty Liver Disease (NAFLD).
Materials and Methods: This prospective, cross-sectional study was performed on 30 NAFLD-patients. Sixteen GRE protocols with different weighting contrast were performed with Siemens 1.5 Tesla with four Echo Times ( . For each sequence, TR or flip angle was changed and other scan parameters were fixed.To assessment of signal intensity changes, Regions of Interest (ROIs) which placed on images were copied into other images. 48 fat indexes were calculated based on three equations (Equ 1-3).
( ) (1)
(2)
( (3); = ln (
Where is the time difference between and .Correlation between biopsy findings and MRI were performed using Pearson coefficient at the significant level of 1%.
Results:Mean fat indexes which obtained from equation 3 have the maximum values in comparison to the other fat indexes. The maximum fat index was 23.58% which related to heavily weighted contrast pulse sequence (sequence 4 TR=50msec, α= defined by equation 3. The minimum fat index was -2.49% which correspond to the minimal weighted pulse sequence (sequence 13TR=200msec, α= defined by equation 2.Relationship between calculated fat indexes and flip angle reveals that, these indexes increased with flip angle especially at low angles. Increasing TR parameter decline fat indexes gradually.Correlational analysis between measured fat indexes and biopsy findings indicate that fat indexes calculated by equation 1 and 3 have slightly stronger correlatecpmpared to resulted data from equation 2.
Conclusion:In general, the relaxation effects more critical than in fat quantification. Diagnostic accuracy of First dual GRE and Triple GRE techniques are better than Second dual GRE. There was no significant difference between First dual GRE and Triple GRE technique. In fat quantification with GRE techniques maybe the third and fourth echoes are unnecessary. Findings suggest that flip angle could be a major factor, if not the only one, causing the overestimation of measured fat content. Consequently, GRE techniques for fat quantification are more desirable with lower flip angle.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
13
13
https://ijmp.mums.ac.ir/article_11857_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11857
Experimental evaluation of thermal stability of PS- MWCNT nanocomposite as a real-time dosimeter
Armin
Mosayebi
Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
author
Shahryar
Malekie
Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
author
Farhood
Ziaie
Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
author
Hamide
Daneshvar
Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
author
text
article
2018
eng
Introduction: Carbon nanotubes (CNTs) are ideal reinforcing fillers for a polymer matrix, because of their nanometer size, high aspect ratio and, more importantly, their excellent mechanical strength, and electrical and thermal conductivity. The CNTs are categorized into two groups: SWCNT and MWCNT. MWCNTs would have diameters ranging from 2 to 100 nm and lengths of up to tens of microns, and they exhibited electrical conductivity as high as 105–107 S/m. The most promising theories for explaining electrical behavior in polymer nanocomposites are based on hopping conductivity models developed to understand the charge transport in disordered semiconductors and amorphous solids. The probability of an electron hopping from one localized state to another one depends on temperature. The authors in the previous articles introduced a novel dosimeter applied in diagnostic and therapeutic dosimetry.
The objective of this experimental work is to evaluate the thermal stability of PS/MWCNT (0.28 wt%) nanocomposite as a real-time dosimeter for the diagnostic and therapeutic purposes.
Materials and Methods: MWCNT with purity of 98 wt%, density of 2.1 g/cm3, outside diameter: 5-15 nm, inside diameter: 3-5 nm, average length: 50 μm, SSA: ~233 m2/g, electrical conductivity greater than 104 S/m was prepared from US Nano Inc, and finally high purity toluene and DCM as the solvents were purchased from Merck Company. PS 1540 with the density 1.05 g/cm3 was supplied by Tabriz Petrochemical Company. Solution processing has been used to prepare 0.28 wt% PS/MWCNT nanocomposite for dosimetry purposes.
Results: Electric resistance of the nanocomposites in different temperatures was measured. Results showed that a positive temperature coefficient (PTC) effect from the room temperature until the glass transition temperature (Tg) for the sample was exhibited, and after that, the negative temperature coefficient (NTC) effect was observed. The maximum discrepancy in the resistance for the sample at room temperature until 50°C was 15%.
Conclusion: In this experimental work, the variation of electric resistance with temperature for the 0.28 wt% MWCNT-PS nanocomposite at room temperature until 80°C was measured, in which indicated a PTC effect before glass transition temperature of polystyrene and NTC effect after that. It can be concluded that for applying this material in a dosimeter, regarding the temperature dependence of the aforementioned nanocomposite, there is need to insert a temperature correction factor in the extracted data for dosimetry purposes. This research work motivates the investigation in depth of the thermal properties behavior of polymer- CNT nanocomposites as a real-time dosimeter.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
14
14
https://ijmp.mums.ac.ir/article_11858_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11858
EPID in vivo Dosimetry
Mahdi
Mohammadi
Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Abbas
Haghparast
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
text
article
2018
eng
Introduction: The most modern radiotherapy devices are equipped with an Electronic Portal Imaging Device (EPID) system which is located on opposite side of the machine’s head. EPID system is often used to setting up the position verification during or between radiotherapy sessions.
Material and Methods: Various types of dosimeters have been used to setting up position verification over the years. According to progress in rapid and high-resolution imaging techniques, EPID as a special type of in vivo dosimetry is used nowadays. Amorphous silicon (A-si) which is applied in radiotherapy centers is the most extensive type of EPID. This EPID is a two-dimensional matrix of pixels. Each pixel acts as a transistor and is connected to a photodiode. Photodiode generates electrical current. An x-ray converter is a copper plate connected to a phosphor plate is needed at the top of the matrix. One of the disadvantages of the former dosimeters was the lack of display of 2D and 3D dose distribution. This property exists in EPIDs. One of the most important features of the dose distribution in IMRT is the focus of high concentration of dose to the target volume and protection of organs at risk (OAR) volumes. This feature provides the delivery of higher doses to target than Three- dimensional conformal radiotherapy (3DCRT). Therefore, small deviation of the designed set-up position in this technique results lower doses to the target volume and significant doses to OARs. 3D display along with proper dosimetric features such as high spatial resolution and digital images produced by EPIDs makes their application in the IMRT technique very prominent. In many studies, the dosimetric results of the EPID have been validated, and several studies have revealed that Utilization of Monte Carlo simulation. Algorithms are proposed to reconstruct the amount of received doses from the EPID images data, based on the EPID pixels in each center. Multiple factors and kernels in algorithms designing are applied for effects such as scatter radiations and off-axis ratios. In some studies, verification of dose in the EPID surface and back it to a certain depth of a definite patient have been done to reconstruct the patient received dose. A number of studies have found that, dose prediction is also done by adding EPID to planning CT scan.
Results: Recent clinical evidence suggests that EPID images should be taken more than once because of patient-positioning errors in each session and patient morphological changes during the course of treatment.
Conclusion: EPIDs can be used in dosimetric purposes. Electronic portal imaging systems are a special type of in vivo dosimeter, Even these imaging systems can provide 2D and 3D dosimetric information from the actual or patient received dose in addition to proper dosimetric properties.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
15
15
https://ijmp.mums.ac.ir/article_11859_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11859
Calculating weighting factors for mixing megavoltage photon beams to achieve desirable dose distribution in Radiotherapy
Mohammad Javad
Tahmasebi Birgani
Radiation Therapy and Medical Physics Department, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences
author
Nahid
Chegeni
Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
Marziyeh
Tahmasbi
Department of Radiology Technology, Paramedicine Faculty, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
Maryam
Hazbavi
Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
text
article
2018
eng
Introduction: Many studies have shown the effects of delivered dose distribution due to the incident photon energy on the tumor and healthy tissues. The ability to access the most appropriate radiation energy is essential to achieve the optimal treatment planning but there is a serious limitation in number of energies available on radiation therapy machines can restrict it.
Materials and Methods: In this research, Electa linear accelerator with 6, 10 and 18MV photon energies and MATLAB software for analytical calculations were applied. The percentage depth dose (PDD) was measured for 6, 10 and 18MV energies in different depths with source-surface distance (SSD) of 100 cm2 for 4×4 to 40×40 cm2 fields. A double exponential function was fitted to the PDDs curves of 6 and 18MV using MATLAB software. Then, using the quality factor equation presented by LaRivere et al. and combination of 6 and 18MV energies, weighting factors to achieve desirable energies for the field of 10×10 cm2 were calculated. To verify the accuracy of this analytical method, PDD of 10MV energy was measured using ion chamber. The PDD obtained from dosimetry of 10MV energy, was compared with the results of mixing 6 and 18MV energies using the gamma index. Moreover, the dosimetric characteristics such as dmax, d50%, d80% and PDD10cm obtained from the mixed energy were compared with ones obtained from the measurement.
Results: The value of the weighting factor of 6MV energy needed for the 10 ×10cm2 field to create dose distribution of 10MV energy using the mix was obtained as equal to 0.57. The obtained results from the mix of 6 and 18 MV energies and dosimetry of 10MV had good compatibility. The gamma index with two criteria of the percent dose difference (∆dM = 0.2cm) and distance to agreement (∆DM = 2%), expect at the points near the edges of the geometric fields, show values less than 1.
Conclusion: The simultaneous use of the high and low photon energies with different weighting factors to achieve desirable energy makes possible the treatment of tumors located at various depths without the need for different modes of energy in the accelerator and leads to decrease in the costs of the equipment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
16
16
https://ijmp.mums.ac.ir/article_11860_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11860
Skin in vivo Dosimetry in Radiotherapy
Mahdi
Mohammadi
Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Razieh
Zaghian
Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
abbas
haghparast
Associate Professor,Medical Physics and Medical Engineering Department, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
text
article
2018
eng
Introduction: Due to the prevalence of skin problems in patients after radiotherapy, skin dose measuring is importance.
Content: Skin in vivo dosimetry means measuring the patient's (or phantom) skin dose during radiotherapy.
According to the ICRP 59, the dose at the depth of 0.07 mm is known as a skin dose. The most radiosensitive epidermis cells are located at this depth.
Several studies have assessed the skin diseases in different areas of the body caused by radiotherapy. The most common problems are skin dermatitis and alopecia depending on the exposure conditions and physiological features of the patient`s body occur several days to several weeks after treatment.
Skin dose in radiotherapy, arising from the primary photon beam, backscatter radiation from more depths, scattering from other equipments in the path of radiation, treatment room and also head leakage. The main challenge of the skin dosimetry is the lack of particle equilibrium at 0.07 mm depth, as well as dosimetry in the build-up region with a high-dose gradient. On the other hand, studies have shown that treatment planning system (TPS), especially in Intensity-modulated radiotherapy (IMRT) and tomotherapy, overestimates the skin dose. Skin dosimetry is more important in modern radiotherapy techniques (such as IMRT) because these treatments use more tangential beams than 3D-CRT, which increase the dose and cause skin problems.
Various dosimeters, such as TLDs, Films, Diodes, and MOSFETs, are used for skin dosimetry, each with advantages and disadvantages. TLDs are small in size, but require long-term pre- and post-processing and are incapable to real-time display of dosimetric information. According to tissue equivalency, the Gafchromic EBT films show acceptable dose accuracy. These films are able to display a 2D dose distribution, but these dosimeters cannot display dosimetric information in real-time. Diodes and MOSFETs, due to their small size, can be appropriate choices for skin dosimetry and provide high spatial resolution.
The newest device proposed for the skin dosimetry is MOSkin, which is based on the MOSFET structure. In addition to its small sensitive volume, this dosimeter acts as a real-time dosimeter. The reproducibility and linearity of the MOSkin response have been approved at the water equivalent depth of 0.07 mm and within the range of 50-300 cGy. This limited dynamic range doesn’t allow this dosimeter to be made in the 2D array. The most important problem with the MOSkin is requirement of a wire to external voltage supply. Presenting a wireless version will be an important step in the field of skin dosimetry in radiotherapy.
Results: Advantages of MOSkin dosimetry outperformed its disadvantages for skin
dosimetry in radiotherapy.
Conclusion: The MOSkin is an appropriate choice for skin in vivo
dosimetry because it has small sensitive volume and acts as a real-time dosimeter.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
17
17
https://ijmp.mums.ac.ir/article_11861_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11861
The Relationship between the Different Prostate Intensity Modulated Radiation Therapy Techniques and Patient’s Anatomical Parameters
Amin
Banaei
Department of Medical Physics, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran
author
Bijan
Hashemi
Department of Medical Physics, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran.
author
Mohsen
Bakhshandeh
Department of Radiology Technology, Faculty of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Bahram
Mofid
Department of Radiation Oncology, Faculty of Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Intensity Modulated Radiotherapy (IMRT) is a common method for treating prostate cancers. Different IMRT methods can apply for irradiating the prostate, but there is not clear that which of these methods can provide better dose distribution for each patient individually. Therefore, the aim of this study was to evaluate the relationship between the different prostate IMRT techniques and Patients anatomical parameters for determining the appropriate IMRT method for each patient regarding to his anatomical parameters.
Materials and Methods: 50 patients with low to high risk prostate cancer were considered for hypo fractionated IMRT (70.2Gy in 26 fractions). CT and MRI (T2 weighted) scans were obtained and imported to the treatment planning system (Eclipse version 11, Varian corporation, USA). Planning tumor volume (PTV) and organs at risk (OARs) were contoured on these images. 4 different IMRT plans including 9 fields, 7 fields, 5 fields and beam angle optimization were created for each patient. Furthermore, the dose distributions of these techniques were evaluated using cost function value that determined the differences between the ideal dose distribution and calculated one. anatomical parameters including OARs volume, joint volumes between OAR and PTV, prostate volume, PTV volume, width and height in the central slice of prostate and femur distance was measured. The relationship between the cost function values with the anatomical parameters were assessed in this study. Results: 9 and 7 fields IMRT had lower cost function values compared to other techniques with increasing the prostate volume, PTV volume and joint volumes between the PTV and OARs. Increasing the OAR volumes, patient’s width and height in the central slice of prostate and femur distance had not any effect in creating differences between the above 4 mentioned IMRT techniques.
Conclusion: Prostate IMRT with 9 and 7 fields can be used interchangeably because of their close value of cost function in all patients, especially they can provide better dose distribution in patients with large PTVs (more than 350cc) and large joint volumes between the OARs and PTV (25 cc for rectum and 50 cc for bladder) compared to 5 fields and beam angle optimization IMRT. All of the mentioned IMRT techniques provided relatively the same dose distributions in patients with small PTV and joint volumes and all range of the other mentioned anatomical parameters.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
18
18
https://ijmp.mums.ac.ir/article_11863_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11863
Dosimetric comparison of conventional and field-in-field techniques in early stage breast cancer radiotherapy
Seyed Mohammad
Hosseini
Department of Medical Physics, Faculty of Medicine, Mashhad University of medical sciences, Mashhad, Iran
Medical physics Research Center, Faculty of Medicine, Mashhad University of medical sciences, Mashhad, Iran
author
Mahdi
Momennezhad
Department of Medical Physics, Faculty of Medicine, Mashhad University of medical sciences, Mashhad, Iran
Medical physics Research Center, Faculty of Medicine, Mashhad University of medical sciences, Mashhad, Iran
Department of Radiotherapy and Oncology, Imam Reza Hospital, Mashhad, Iran
author
text
article
2018
eng
Introduction: Breast conserving surgery followed by adjuvant radiotherapy (RT) of the whole breast is accepted as the treatment of choice in early stage breast cancer. Due to breast irregularities, it is difficult to access homogenous dose distribution with conventional techniques. Currently, it is possible to use varied breast irradiation techniques, such as field- in-field (FIF), to apply a more homogenous distribution of doses within target volumes, and organs at risk (OAR) sparing which lead to achieve better treatment outcome. This study aimed to compare conventional and FIF techniques dosimetrically
Materials and Methods: Twenty patients with early-stage breast cancer underwent computed tomography (CT) with a 16 Slice CT simulator; datasets were transferred to the treatment planning system (TPS) via a digital imaging communications in medicine (DICOM). Two different treatment plans were created for each patient by the same medical physicist: a wedge base (conventional) plan and a FIF plan. Then, dosimetric and monitor unit (MU) results were compared.
Results: Dosimetric indices in the planning target volume (PTV) were more satisfying with the FIF technique than with three dimensional-conformal RT (3D-CRT). FIF reduced the maximum doses of PTV and MU. In addition, the FIF technique reduced doses to the heart (in left-side irradiation cases) and ipsilateral lung by 7% and 8%, respectively. FIF also significantly reduced V40 (volume receiving 40 Gy) of heart in left side breast irradiation. V20 of lung (volume receiving 20 Gy), and also doses to the contralateral lung did not differ significantly.
Conclusion: FIF can produce more homogenous doses within the PTV, and reduce doses to the OAR. Moreover, by using the FIF technique in breast irradiation, MUs required for therapy are significantly decreased compared with that required by 3D-CRT.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
19
19
https://ijmp.mums.ac.ir/article_11864_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11864
Radioiodination of a natural toxin (ICD-85) for fighting cancer
Seyed Pezhman
Shirmardi
Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
Mostafa
Erfani
Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
Zahra
Pakdin Parizi
Mashhad, Razavi Hospital, Department of Nuclear Medicine
author
Abbas
Zare Mirakabadi
Department of Venomous Animals and Antivenom Production, Razi Vaccine and Serum Research Institute, Agriculture Research Education and Extension Organization, Karaj, Iran
author
Reza
Bagheri
Department of Venomous Animals and Antivenom Production, Razi Vaccine and Serum Research Institute, Agriculture Research Education and Extension Organization, Karaj, Iran
author
text
article
2018
eng
Introduction:
Many molecules can be labeled by iodine. Some of labeled substances are used for investigations of cancer treatment, biodistribution study in body, receptor binding, secrete pathway etc. Peptides are biomolecules and can be labeled by 131Iodine. ICD- 85 is a tri-peptide derived from Iranian brown snake venom and scorpion venom. This tri-peptide treats cancer by inducing apoptosis. In this study, radioiodination and normal mice biodistribution of ICD-85 was performed by different values of Chloramine-T.
Materials and Methods:
This tri-peptide isolated from snake and yellow scorpion venom by HPLC and gel chromatography. Labeling with iodine-131 was done by Chloramine-T method. The reaction was performed by different values of chloramine T. The values 50, 100, 150, 200, 250 micrograms were chosen for this radiolabelling. Stability of labeled tripeptide was investigated in phosphate buffer saline for one day. Biodistribution study was studied in normal mice.
Results:
The results show that, the use of 20 micrograms of Chloramine-T leads to radiochemical purity of more than 45 percent. The stability of labeled compound was considerable (more than 40%) after 24 hours. Biodistriution study in normal mice show that, the liver is organ of target.
Conclusion:
The natural toxins such as snake and scorpion venoms can be labeled with radionuclides and used as cancer treatment agent.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
20
20
https://ijmp.mums.ac.ir/article_11865_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11865
A Specific Patient Quality Assurance (PSQA) procedure for a Co-60 source based High Dose Rate Brachytherapy
Mohammad Hadi
Gholami
Mahdieh Radiotherapy and Oncology charity Centre, Hamadan. Iran
Islamic Azad University, Science and research branch, Tehran, Iran
author
Mohammad
Mohammadi
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
Ramin
Jaberi
Tehran University of Medical Sciences • Department of Radiation Oncology, Tehran, Iran.
author
Abdolazim
Sedighi
Department of radiation oncology, University of medical science, Hamedan, Iran
author
text
article
2018
eng
Introduction: In radiation therapy, accurate dose determination and precise dose delivery to the tumor are directly associated with better treatment outcomes in terms of higher tumor control and lower post radiation therapy complications. The current study aims the development and clinical application of the Patient Specific Quality Assurance (PSQA) procedures for nasopharyngeal and Tongue cancer treated using a cobalt-60 based high-dose rate brachytherapy.
Materials and Methods: In this study, patient-specific quality assurance tools for brachytherapy in nasopharyngeal and Tongue cancers were utilized using a radiometric film dosimeter system through a gamma index for comparison. Also, with the association of dose distribution measured at surface area, and applying a reverse method, the calculated dose distribution at the region of interest were compared with those resulted from a treatment planning system. All results were also compared with those achieved by a Monte Carlo simulation classified as gold standard for the project. We also designed and evaluated two phantoms in this study. The first phantom designed based on the BALTAS phantom and the second one was created as a special phantom for brachytherapy applicators used for Nasopharyngeal and Tongue cancers. The same passing criteria used for external beam QA (3%/3mm), were applied. Finally, the PSQA system’s sensitivity to source positional errors was investigated by introducing intentional and controlled mistakes on selected patient’s plans.
Results: Results presented in this study demonstrated that radiochromic film dosimetry based PSQA for brachytherapy can be used not only for patient specific quality assurance, but also as a part of the commissioning process and periodic QA .
Conclusion: Patient Specific Quality Assurance tasks should be extended for all Radiotherapy tasks including Brachytherapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
21
21
https://ijmp.mums.ac.ir/article_11866_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11866
Respiratory motion correction in prostate cancer positron emission tomography: A study on patients and phantom simulation
Khadijeh
Bamneshin
Iran University of Medical Science, Tehran, Iran
author
Ahmad
Bitarafan rajabi
Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, IR
author
Seied Rabi
Mahdavi
Medical Physics Department, Tehran University of Medical Science, Tehran, Iran
author
Parham
Geramifar
Asisstant Professor, Tehran University of Medical Sciences
author
Seied Mohsen
Shahabi
Shadi Beheshti of Medicai Science, Tehran, Iran
author
text
article
2018
eng
Introduction: To investigate the effects of breathing cycle and tree diaphragm motions on prostate cancer tumors standard uptake value (SUV) during positron emission tomography (PET) and to correct it.
Materials and methods: Respiratory motion traces were simulated on the common patient breathing cycle and tree diaphragm motions using the 4D NCAT phantom. Lesions with different activities and diameters were simulated in prostate. This study was conducted in two phases. In the first phase; the generated PET sinograms taken from GATE (Geant4 Application Tomography Emission) Monte Carlo simulations corrected using computed tomography attenuation correction involving the cycle. In the next phase; on the obtained images, the motion-correction was carried out using software for Tomographic Image Reconstruction (STIR). By considering respiration- averaged computed as a true value, the SUVs were measured and analyzed for different motions.
Results: In uncorrected measurements, the mean, minimum and maximum SUVs were 0.4%, 0.09% and 2% respectively, whilst in corrected measurements, these value were reported as 3.5%, 0.7% and 14% respectively.
Conclusion: The respiratory motion-induced errors in tumor quantification and delineation. The SUVs depending on the phase of the raspatory. Motion correction could enhance the SUVs in prostate cancer PET.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
22
22
https://ijmp.mums.ac.ir/article_11868_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11868
Localization of electron virtual SSD in a Siemens-Primus linear accelerator: Comparison of measurements with Monte Carlo simulation
Mohammad Hadi
Gholami
Mahdieh Radiotherapy and Oncology charity Centre, Hamadan. Iran
Islamic Azad University, Science and Research Branch, Tehran, Iran
author
Mohammad
Mohammadi
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran.
author
Alireza
Khoshghadam
Mahdieh Radiotherapy and Oncology charity Centre, Hamadan. Iran
Islamic Azad University, Science and Research Branch, Tehran, Iran
author
Abdolazim
Sedighi
Department of radiation oncology, University of medical science, Hamedan, Iran.
author
text
article
2018
eng
Introduction: Because of importance of impact of the Source to Surface Distance (SSD) in determining of monitor unit for electron-therapy, it is essential to know the Virtual Source Position (VSP) for electron beam for a linear therapeutic accelerator for each energy and field size.
, especially using the Khan method (photo distance squared method) And compare the results with Monte Carlo.
Materials and Methods: The VSP was measured for a Siemens- Primus linear accelerator for all available electron beams (5, 7, 8, 10 and 12 MeV) and for five applicator sizes (5×5, 10×10, 15×15, 20×20, 25×25 cm2) available at the department in Mahdieh Radiotherapy and Oncology Charity center in Hamadan. A theoretical method (known as Khan’s method) was applied to estimate VSP for all electron energies and for all potential applicators. A valid MCNPX Monte Carlo code was then used to evaluate the results achieved through the measurements.
Results:The results showed a significant difference between Monte Carlo those were found to be ~4% and 5.2% for F4 and F8 tally approaches, respectively.
Conclusion: MonteCarlo simulation code with correction factor can be used as an alternative approach to verify measurements acquired for VSD and other datasets applied for treatment Planning Systems.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
23
23
https://ijmp.mums.ac.ir/article_11869_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11869
Evaluation of dose distribution and dose gradient in brachytherapy cylindrical applicators using a dedicated Phantom for Iridium-192 and Cobalt-60 HDR sources
Mohammad Hadi
Gholami
Islamic Azad University, Science and research branch, Tehran, Iran
Mahdieh Radiotherapy and Oncology charity center, Hamadan, Iran
author
Mohammad
Mohammadi
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
Abdolazim
Sedighi
Department of radiation oncology, University of medical science, Hamedan, Iran
author
Ramin
Jaberi
Department of Radiation Oncology, Tehran University of Medical Sciences, Tehran, Iran
author
Fahimeh
Rezaei
MSc of Medical physics, Department of Medical physics, Kermanshah University of Medical sciences, Kermanshah, Iran
author
text
article
2018
eng
Introduction: A study was performed to evaluate radiation dose distribution and dose gradient around cylindrical applicators for high-dose-rate (HDR) brachytherapy systems with 192Ir, 60Co brachytherapy source applied for rectal and vaginal cancers treatments.
Materials and Methods: Two additional computed tomography (CT) based plans were generated using a dedicated Phantom for both 60Co source and 192IridumHDR sources. The phantom contains a film and TLD-100 position on the top and peripheral areas, and a rectum cylinder with 1.5 cm insert caps into the phantom. Dose coverage of 5-mm shell surrounding the cylinder, was then evaluated for both scenarios.
Results:A significant dose reduction from the expectation dose for 192Ir at the central points of the cylinder tip was observed. The results were then verified by measurements through radio- chromic film and TLDs.
Conclusion: Both 60Co and 192Ir sources were found to be suitable HDR sources for vaginal treatment using a cylindrical applicator with advantages of reducing radiation exposure to Organ At Risks (OARs) in the lower dose range, and appropriate prescribed dose to the target
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
24
24
https://ijmp.mums.ac.ir/article_11879_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11879
Automatic Segmentation of the Gross Tumor Volume in Prostate Carcinoma Using Fuzzy Clustering in Gallium-68 PSMA PET/CT Scan
Khadijeh
Bamneshin
Iran University of Medical Science, Tehran, Iran
author
Ahmad
Bitarafan rajabi
Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, IR
author
Seied Rabi
Mahdavi
Medical Physics Department, Tehran University of Medical Science, Tehran, Iran
author
Parham
Geramifar
Asisstant Professor, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Modern radiotherapy (RT) techniques allow a highly precise deposition of the radiation dose in tumor. So, high conformal tumor doses can be reached while sparing critical organs at risk.
Materials and Methods: This study was conducted in three phases. In the first phase; Fourteen patients with primary or recurrent prostate cancer receive Gallium-68 PSMA PET/CT planned 3D conformal or intensity modulated radio therapy. In the second phase; fuzzy clustering method to definition the gross volume tumor in prostate. In the next phase; increasing the dose in the tumor according to the functional and molecular information assessed by combined PET/CT imaging and result of clustering.
Result: The mean standard uptake value (Suv) was 6.2 in the lesion of the prostate. To administer 75.6Gy to the entire prostate with a boost dose to 84Gy, was feasible.
Conclusion: The additional of the simultaneous integrated boost(SIB) was associated with greater control but not toxicity.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
25
25
https://ijmp.mums.ac.ir/article_11880_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11880
A local study on diagnostic reference levels estimation for children computed tomography
Reza
Afzalipour
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Hamid
Abdollahi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Salman
Jafari
Department of Radiology Technology, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran
author
Seied Rabi
Mahdavi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: The Diagnostic reference levels (DRLs) play a critical role in the optimization of radiation dose especially, in some conditions like pediatrics. They are useful indicators by which the radiologists can be aware of delivered excess radiation doses to the patients, and take corrective actions if necessary. In order to meet some requirements for establishing the national computed tomography DRLs tables, much studies are needed all around the country.
Materials and Methods: All active computed tomography (CT) scanners in public and private centers in Tehran were identified and checked for quality assurance and control certification. Eleven centers were chosen to be studied according to CT examination frequencies. Weighted CT dose index (CTDIw) and dose length product (DLP) for head, sinus, chest and abdomen/pelvis scans of children were obtained from scanner’s operator consoles and classified into four groups based on their ages (A; <1 year, B; 1-5 years, C; 5-10 years and D; 10-15 years). The 3rd quartiles of CTDIw were considered as DRLs and compared with the reported European Union (EU) and United Kingdom (UK) ones.
Results: DRLs for head, sinus, chest and abdomen/pelvis scans were found to be 86.76, 31.33, 6.33, 7.65 mGy; 43.38, 31.33, 6.33, 7.65 mGy; 43, 31.33, 6.33, 7.65 mGy and 44.53, 31.33, 6.33, 7.65
mGy in the four groups (A-D) respectively. They are lower than the reported DRLs in EU and UK.
Conclusion: There are variations in the radiation dose between the CT centers and identical scanners indicating the necessity for dose optimization. The data reported in this study can be remarkably useful in this concern.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
26
26
https://ijmp.mums.ac.ir/article_11881_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11881
Evaluating variation of Hot Spot Location in order to radiobiological calculation of Organ at Risk in High-dose- rate Brachytherapy of Cervical Cancer
Ramin
Jaberi
Brachytherapy Physicist, Tehran University of Medical Sciences , Department of Radiation Oncology, Tehran, Iran
author
Mohammad Hadi
Gholami
Mahdieh Radiotherapy and Oncology charity Centre, Hamadan. Iran
Islamic Azad University, Science and research branch, Tehran, Iran
author
Abdolazim
Sedighi
Department of radiation oncology, University of medical science, Hamedan, Iran
author
Mohammad
Mohammadi
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
Razieh
Zaghiyan
MSc student of Medical physic, Kermanshah university of medical science, Kermanshah, Iran
author
text
article
2018
eng
Introduction: Gynecological malignancies present challenges in determining an appropriate volumetric dose due to the highly variable physiologic activity of the surrounding tissue. Because of the high doses used in brachytherapy, surrounding structures have the potential to move around in the dose region and receive unknown amounts of radiation. Calculating hotspot region from reference point such as PIBS (Posterior Inferior Border of Samphys pubis) location could overcome challenges in determining the true delivered dose through a dose accumulation process.
Materials and Methods: Data for patients treated with a vaginal cylinder or tandem and ovoids were imported into HDRPLUS software. The bladder, rectum and applicators were contoured and reconstructed on each computed tomography (CT) scan. The distance between high dose area and samphyspubis were reported. The PIBS is a fixed point and we can measure the distance from it for comparison of changing location in several fraction of treatments. . Point doses, D2cm3 , were used as a comparison value for each method
Results: The cylinder set had a DSP (Distance from Samphys Pubis) to hotspot ranging from 1.2 to 5 cm for bladder and 1 to 6 cm for rectum. The tandem and ovoids set of patients had a DSP ranging from 0.6 to 3 for rectum and 1.5 to 7cm for Bladder.
Conclusion: From this study we can use radiobiological EQD2 model for computing tolerance dose to OAR, so this method is a strict but sure approach for calculation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
27
27
https://ijmp.mums.ac.ir/article_11882_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11882
Assessment of Diffusion Anisotropy of White Matter in Areas of the Brain with crossing fibers: A simulation study
Masoud
Jabari
PhD student of Medical Physics, Tarbiat Modares University, Medical Physics Department, Tehran, Iran
author
text
article
2018
eng
Introduction: We present a model of simulation of diffusion in white matter. This model has been used in Diffusion Weighted Imaging researches as a tool for employing cylindrically constrained two-tensor models to identify two independent directions within a voxel and assessing the orientation angle as a parameter that influence on fractional anisotropy.
Materials and Methods: We generate a random number generator with Maxwell-Boltzmann distribution. This distribution is chosen from quantum mechanics theory and is a physical assumption for the initial velocity of molecules before they strike the cylindrical geometry. First position of a molecule generates randomly and then this molecule can transmit to every point on the cylinder. So by determine a random θ and either a random Φ, we determining a random orientation for this molecule and until the molecule haven’t stroked a point on the cylinder this orientation not changed since the collision between molecules is not important because of their tiny dimensions. After tracing the molecules and recording all of the collision point’s characteristics, we can calculate Mean Free Path (MFP) along all directions, we can calculate diffusivity (D) along all directions. So we can calculate eigenvalues (λ1, λ2, λ3) and eigenvectors (V1, V2, V3). Therefore we have collision points data on a cylinder rotated by arbitrary angle so mean free paths and index vector associated to this state can be calculated.
Results: FA values for all states that involve only one fiber along a determined direction have calculated from three values of index vector. An overall FA value is calculated by situated two fiber crossing at an arbitrary angle in a voxel. Also variation of FA value with variation of angle between two fibers in a voxel have been calculated and assessed how this angle can change FA values.
Conclusion: In this paper an evaluation of FA value variation with variation of angle presented and results shown with increasing in angle between two bundle, FA value decreases. .FA has its must value when two bundle are oriented at the same direction and least value when they are crossing at 180.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
28
28
https://ijmp.mums.ac.ir/article_11883_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11883
Assessment of two different dose distribution algorithms (Clarkson and Superposition) in PCRT3D treatment planning system for Esophagus Cancer by using 3DCRT technique
Malihe
Rezaie Yazdi
Medical physicist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
Maryam
Rezaie Yazdi
Medical physicist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
Fathollah
Bouzarjomehri
Professor of Medical Physics, Department of Medical Physics Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Narges
Kheirollahi
Medical physicist of Imam Reza Radiotherapy Oncology Department, Imam Reza Hospital, Mashhad, Iran.
author
Payam
Izadpanahi
Radiation Oncologist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
Ahmadreza
Sebzari
Radiation Oncologist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
Kaveh
Shirani Tak Abi
Medical Physicist of Sina Radiotherapy Oncology Department, Bu Ali Hospital, Tehran, Iran.
author
text
article
2018
eng
Introduction: The functionality and quality of any treatment planning system (TPS) strongly depends on the type of Algorithm which is used by it. Obviously, the role of dose distribution algorithms in calculation of prescribed dose inside the tumor in modern radiotherapy techniques has more important than past to achieve the best clinical outcomes, especially in tumors which are placed in lung or near it like Esophagus cancer.
The aim of this study is to evaluate and comparison of efficiency and accuracy of two dose distribution algorithms, Clarkson and Superposition which are using in PCRT 3D treatment planning system to calculate the dose distribution in Three- Dimensional Conformal Radiotherapy (3D-CRT) for Esophagus cancer cases.
Materials and Methods: In this study ten patients with esophageal cancer were planned by Clarkson and Superposition algorithms. Treatment plan of the patients were created with a photon beam of 6 MV. Commercially available PCRT3D version6 (made in Spain) Planning system was used to calculate dose in ten planed patients. For this goal and to compare two dose distribution algorithms, the statistical analysis was performed by comparing Conformity Index and Homogeneity Index for target.
Results: The maximum value of variation between algorithms for PTV in Dmin, Dmax, and Dmean were 11.7%, 8.3% and 0.73%, respectively. The maximum deviation of variation observed between algorithms in OAR's consist of Dmean is 8.9% for Left lung 7.14% for Right Lung and 2.65% for Spinal cord. Significant variation between algorithms for Homogeneity Index values is 9.06% and highest Percentage oscillation between algorithms for Conformity Index values are 6.33%.
Conclusion: According to this study and because of the different results which was driven from treatment planning, significant care should be taken account when calculating treatment plans, due to different dose calculation algorithm may influence treatment planning as well as clinical results.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
29
29
https://ijmp.mums.ac.ir/article_11884_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11884
A Microdosimetry model of kidney for nephrotoxicity due to internal radiation therapy
Masoud
Jabari
Medical Physics Department, Tarbiat Modares University, Tehran, Iran
author
Hossein
Rajabi
Medical Physics Department, Tarbiat Modares University, Tehran, Iran
author
text
article
2018
eng
Introduction: We describe a nephron-based dosimetry model for renal toxicity for radiopharmaceutical therapy suited to the nonuniform activity distribution of radiopharmaceutical. In radiopharmaceutical therapy, renal toxicity is observed while whole-kidney and renal cortex absorbed dose values are below toxicity thresholds established by external beam and targeted radiope ptide therapy. Average dose to a kidney is not a perfect index to quantify the damage due to radiation. Obviously, a damage to a small area of nephron can lead to its dysfunction while the average dose may be lower than the tolerance level. The aim of this study is to estimate the absorbed dose along a typical nephron as an index to predict the possible damages to the nephron.
Materials and Methods: Using Gate/GEANT4 Monte Carlo toolkit an idealized nephron model is created using geometrical and anatomical parameters taken from the literature. These samples also provide the data for volume of occupancy of the different compartments of the nephron in the kidney: glomerulus vs. proximal tubule vs. distal tubule. The selected pharmaceuticals were considered attached to radionuclide of choice (Tc-99m, Y-90, Lu-177, In-111). Radionuclides were distributed in the different components of nephron, Monte Carlo simulations were run, the absorbed doses to the model components (self-absorption and cross-absorption) were calculated. Different physics model in Geant4(Penelope, Livermore and Geant4-DNA) were compared together as an evaluation of the results.
Results: Preliminary results show an absorbed dose to the proximal tubule and glomerular cells approximately 2 times greater than that to the kidney as a whole. This difference in conjunction with the relative biological effect (a factor of about 5) would be consistent with the toxicity observed in the experiments. We observed a strong linear relationship between the results obtained using the condenced-history physics model and those derived using the track-structure. This similarity is verified by previous study in spherical geometry for cellular dosimetry. The agreement between data series was evaluated by Blant-Altman analysis.
Conclusion: The nephron model enables optimal implementation of treatment and is a critical step in understanding nephron toxicity for human translation of radiopharmaceutical therapy
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
30
30
https://ijmp.mums.ac.ir/article_11885_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11885
Generating the synthetic CT (sCT) and synthetic MR (sMR: sT1w/sT2w) images of the brain using atlas based method
Fariba
Farhadi Birgani
Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohamad Javad
Tahmasebi Birgani
Radiation Therapy and Medical Physics Department, Golestan Hospital, Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Fatemeh
Maghsoodinia
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Roghayeh
Kamran Samani
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
text
article
2018
eng
Introduction: Radiation therapy planning (RTP) is one of the clinical applications in which both CT scan and MRI are used. MR and CT images are applied to determine the target volume and calculation of dose distribution, respectively. In addition, using two imaging modalities increases the department workload and cost. In this study, an algorithm was presented to create synthetic CT (sCT) and synthetic MR (sMR: sT1w/sT2w) images consequently CT or MR images are not taken from patient.
Materials and Methods: The synthetic CT (sCT) and synthetic MR (sMR: sT1w/sT2w) images was generated by atlas based method. The dataset consisted of MR and CT paired images from 17 brain RT patients. To generate sCT/sMR image, first each MR/CT atlas was registered to the MR/CT target image, the resulting transformation was applied to the corresponding CT/MR atlas which created the set of deformed images. Then, deformed images were fused to generate a single sCT/sMR. The sCT/sMR was compared with the real CT/MR images using the MAE.
Results: The evaluations performed by MAE showed a good agreement between the sCT/sMR and real CT/MR images. The results represented 72±11.3 HU, 51±7.3 image intensity and 64±7.3 image intensity for sCT, sT1w and sT2w, respectively.
Conclusion: This method showed that sT1w images have lesser MAE with respect sT2w. As a result, CT in transferring the brain tissues geometry to sT1w is more successful than sT2w. Also, the sCT images based T1w are in better agreement with real CT than sCT images based T2w.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
31
31
https://ijmp.mums.ac.ir/article_11886_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11886
Evaluation of Thyroid Gland Irradiation in Women with Breast Cancer during Radiotherapy with different Radiation Energies at Supraclavicular Region
Marjaneh
Mirsadraie
Reza Radiation Oncology Center, Mashhad, Iran
author
Shokoufeh
Mohebbi
Reza Radiation Oncology Center, Mashhad, Iran
author
Mehdi
Silanian toosi
Mashhad University of Medical Sciences, Mashhad, Iran
author
Hojjat
Khalili
Reza Radiation Oncology Center, Mashhad, Iran
author
text
article
2018
eng
Introduction: During treatment of breast cancer, Radiotherapy to the Supraclavicular fossa region results in absorption of radiation by the thyroid gland and consequently leads to hypothyroidism in 40% of patients. The aim of this study was to compare thyroid gland radiation absorption during radiotherapy with different anterior-posterior beam radiation of 6-15 and 15-15 MV photon beam energies.
Materials and Methods: 29 patients with breast cancer were recruited to this study. Adjuvant radiotherapy with a total dose of 50 Gy was performed for each participant. Thyroid gland dosimetric measurements were evaluated including, mean dose, minimum and maximum dose, and V20, V30, V40, and V50 (percentage of thyroid volume receiving ≥20 Gy, ≥30 Gy, ≥40 Gy, and
≥50 Gy, respectively). The irradiation delivered doses were measured using Prowess Panther treatment planning system (Version 5.5). All data were evaluated using SPSS software.
Results: 29 subjects with mean age of 53.4±9.4 were studied. According to the obtained results, at 15- 15 MV energies, a significantly lower dose was absorbed by the thyroid gland, was observed in contrast to their counterparts who were treated with 6-15 MV photon beam energies.
Conclusion: Using 15-15 MV photon beam energies field can significantly reduce the absorbed dose to the thyroid gland and consequently can reduce the risk of developing hypothyroidism in breast cancer patients treated with radiotherapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
32
32
https://ijmp.mums.ac.ir/article_11887_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11887
Optimization of the brain tumor MR images classification accuracy using the optimal threshold, PCA and training ANFIS with different repetitions
Mohamad Javad
Tahmasebi Birgani
Radiation Therapy and Medical Physics Department, Golestan Hospital, Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Fariba
Farhadi Birgani
Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Nahid
Chegeni
Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction: One of the leading causes of death among people is brain tumors. Accurate tumor classification leads to appropriate decision-making and providing the most efficient treatment to the patients. This study aims to optimize of the brain tumor MR images classification accuracy using the optimal threshold, PCA and training Adaptive Neuro Fuzzy Inference System (ANFIS) with different repetitions.
Materials and Methods: This procedure used in this study consists of five steps: (1) T1, T2 weighted images collection, (2) tumor separation with different threshold levels, (3) feature extraction, (4) presence and absence of feature reduction applying principal component analysis (PCA) and
(5) ANFIS classification with 0, 20, and 200 training repetitions.
Results: ANFIS accuracy was 40%, 80% and 97% for all features and 97%, 98.5% and 100% for the 6 selected features by PCA in 0, 20 and 200 training repetitions, respectively.
Conclusion: The findings of the present study showed that accuracy can be raised up to 100% by using an optimized threshold method, PCA and increasing training repetitions.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
33
33
https://ijmp.mums.ac.ir/article_11888_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11888
Comparison and evaluation of dosimetric and radiobiological parameters in two different treatment plans in stomach cancer by use of 3D CRT
Maryam
Rezaie Yazdi
Medical physicist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
Malihe
Rezaie Yazdi
Medical physicist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
Kaveh
Shirani Tak Abi
Medical Physicist of Sina Radiotherapy Oncology Department, Bu Ali Hospital, Tehran, Iran.
author
Hassan Ali
Nedaie
Assistant Prof. of Medical Physics, Radiotherapy Oncology Department, Tehran University of Medical Sciences, Tehran, Iran.
author
Narges
Kheirollahi
Medical physicist of Imam Reza Radiotherapy Oncology Department, Imam Reza Hospital, Mashhad, Iran.
author
Payam
Izadpanahi
Radiation Oncologist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
Reza
KhodaBakhshi
Radiation Oncologist, Consultant and Executive Director of Sina Radiotherapy Oncology Department, Bu Ali Hospital, Tehran, Iran.
author
Farid
Nezhad Dadgar
Assistance Prof. of Radiation Oncology, Sina Radiotherapy Oncology Department, Bu Ali Hospital, Islamic Azad University, Medical College, Tehran, Iran.
author
text
article
2018
eng
Introduction: In 3DCRT the number of therapeutic fields has dramatic impact on treatment results
especially in stomach cancer. Traditionally, for radiotherapy of stomach cancer the therapeutic procedure was using two fields (AP- PA or AP Lateral with wedge) to achieve smooth and homogeneous dose distribution in tumor. But nowadays, adding lateral or oblique fields to aforementioned techniques lead to reducing dose to organ at risks (OARs) like spinal cord, liver, both kidneys and better dose distribution in tumor. Moreover, there
are a several ways to evaluate traditional and novel techniques in 3DCRT for stomach cancer. for example, Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) from radiobiological point of view and Homogeneity Index (HI), Conformity Index (CI) as a dosimetric parameters. Thus, the aim of this study is to assess and compare two different plans in stomach cancer by using homogeneity Index, conformity index, TCP and NTCP as guidance criteria in 3DCRT.
Materials and Methods: In this study, 10 patients with stomach cancer were chosen. Two different of treatment plans; three fields (AP, PA, and lateral) and four fields (AP, PA and two laterals) were prepared. A photon beam of 6MV quality was used for both treatment plans in PCRT 3D as treatment planning system. Prescribed dose was 5o.4 Gy for tumor. Therapeutic aim for all treatment plans was to deliver at least 95% of prescribed dose to 97% of target volume while sparing organ at risks. The normalization of each plan followed the recommendation of ICRU report 50. The tumor volume selected for calculating the HI, CI and TCP and OARs for NTCP.
Results:Average ratio of the calculated parameters in treatment plans of four fields over three fields with standard deviation (Mean /SD) was 1.05±0.13 for CI and 0.99±0.01 for HI. In addition, Treatment ratio for four fields over three fields was 1±0.02. Damage ratio to spinal cord and liver was 0.57±0.18 and 2.09±0.93 respectively for treatment plans with four fields in comparison of treatment plans by using of three therapeutic fields.
Conclusion: Results show that, HI and CI parameters are approximately equal in two treatment plans. Therefore, both of the treatment plans are acceptable for clinical use. Assessment TCP and NTCP radiobiology parameter determined that, tumor control probability for both treatment plans are same but, damage probability of liver in three field treatment plan is less than over four fields while damage probability of spinal cord in four field treatment plan is lower than three fields treatment planning.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
34
34
https://ijmp.mums.ac.ir/article_11889_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11889
Evaluation of methods of co-segmentation on PET/CT images of lung tumor: simulation study
Elham
Kashian
MSc student of Biomedical Engineering, Department of Biomedical Engineering, University of Medical Sciences, Kermanshah, Iran
author
Hadi
Taleshi Ahangari
Assistant professor, Department of Medical Physics, University of Medical Sciences, Semnan, Iran
author
Vahab
Dehlaghi
Associate Professor, Department of Biomedical Engineering, University of Medical Sciences, Kermanshah, Iran
author
Karim
Khoshgard
Assistant professor, Department of Medical Physics, University of Medical Sciences, Kermanshah, Iran
author
Pardis
Ghafarian
Assistant professor, Shahid beheshti University of Medical Sciences, Tehran, Iran
Clinical physicist, Masih Daneshvari Hospital, Tehran, Iran
author
Hossein
Mousavie Anijdan
Assistant professor, Department of Medical Physics, University of Medical Sciences, babol, Iran
author
Shiva
Zarifi
MSc student of Medical Physics, Department of Medical Physics, University of Medical Sciences, Semnan, Iran
author
text
article
2018
eng
Introduction: Lung cancer is one of the most common causes of cancer-related deaths worldwide. Nowadays PET/CT plays an essential role in radiotherapy planning specially for lung tumors as it provides anatomical and functional information simultaneously that is effective in accurate tumor delineation. The optimal segmentation method has not been introduced yet, however several methods have been proposed up to now. Lake of suitable gold standard for correct evaluating of segmentation algorithms is the most important reason of it. The Monte-Carlo simulations are the ideal tool since it allows a complete description of data not accessible in the case of patient studies. The aim of this study was to simulate clinically realistic Monte-Carlo PET/CT data, obtained using the NCAT numerical phantom and the GATE simulation tool, to compare precision of 3 co- segmentation algorithms on lesion delineation.
Materials and Methods: In this study, detection system and geometry of PET/CT scanner were modeled using GATE simulation toolkit. After validation of simulated scanner and modification of GATE parameters, a digital phantom was designed using NCAT digital phantom based on patient's information extracted from PET/CT images. Then 5 sphere-shape tumors with different sizes were created in lung as lesions. In order to implement co-segmentation algorithms, simulated images of phantoms were merged with CT images by AMIDE (a Medical Image Data Examiner). Finally simulated pulmonary lesions were segmented using 3 co-segmentation matlab codes: Watershed, Region growing and Graph cut. Comparing of these methods was performed by parameters included: Tumor Diameter (TD) and Gross Tumor Volume (TV). At the end, results of PET segmentation and PET/CT segmentation were compared as well in order to evaluate effect of using CT information in precision of tumor volume detection.
Results: TD and GTV measured from PET/CT images segmented by region growing had difference less than 5% from gold standard and this method was efficient for all 5 tumor sizes. Graph cut outcomes had GTV and TD difference less than 15 % and it could not detect tumors with size less than 3 cm. watershed did not have correct outcomes. The co-segmented tumor volume on PET-CT image was most strongly correlated with specified tumor volume of phantoms compared with co-segmented tumor volume on PET individually.
Conclusion: Results demonstrate that among 3 segmentation algorithm, region growing had the most accurate outcomes and watershed was the weakest method. It also showed accuracy of segmentation methods was depended on tumor size especially for graph cut. Tumors of less than 3 cm were indistinguishable by graph cut method and watershed was an incapable algorithm for tumor delineation. Accuracy on GTV and TD measurement using all 3 segmentation methods was largely improved on PET/CT fused image compared to PET image individually as anatomical information of CT.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
35
35
https://ijmp.mums.ac.ir/article_11929_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11929
Optimum neutron energy simulation in treatment of head and neck cancer at different depths in the BNCT method
Fateme
Sabery Balajaddeh
Department of physics, Sciences Facility, Golestan University P. O. Box 49138-15759, Gorgan, Iran.
author
Mohadeseh
Golshanian
Department of reactor, nuclear science and technology research institute, Tehran, Iran
author
Vahid
Zanganeh
Department of physics, Sciences Facility, Golestan University P. O. Box 49138-15759, Gorgan, Iran.
author
text
article
2018
eng
Introduction: Recently head and neck cancer has pay attention to many researchers. Its therapeutic methods include surgery, chemotherapy, radiotherapy and Boron neutron capture therapy (BNCT). BNCT is better than conventional radiotherapy because it targets the tumor cell. This method involves two steps of infusion of stable 10B and then neutron radiation with a suitable intensity and energy.
The BNCT in combination with boronphenylalanine (BPA) and borocaptate sodium (BSH) that was make using the epithermal neutron. BSH and PBA are used as 10B carriers. Epithermal neutrons reach to thermal transiting through tissues of the body. When 10B absorbed thermal neutrons, the α and 7Li particles produced in the 10B (n, α) 7Li reaction are of high linear energy. Transfer radiation have a short range of one cell diameter.
Materials and Methods: Monte Carlo simulations were performed with MCNPX2.6 and RO31 MIRD phantom. The neutron source was employed the surface disk with 10 diameters and the range of energy was considered from 1ev-10Kev. The results of neutron and gamma dose at various depths was calculated using tally F4 and F6 in MCNPX2.6 code.
Results: Relative Dose was obtained at various depths based on energy changes for gamma, fast and thermal neutron.
The results of this study have shown increases of optimum energy as the tumor get deeper respect to the skin. In addition, an analytical relation was proposed for energy optimization with the position of the tumor.
Conclusion: The optimum neutron energy dependence was investigated for neck tumor in different depths. These results provide useful information to the physicians to choice best optimum energy neutron beam in BNCT method.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
36
36
https://ijmp.mums.ac.ir/article_11930_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11930
Comparison between MRS and DWI in MRI of breast cancer
Zohreh
Bidari
B.S. student of radiology, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Iran.E-mail : zohreh.bidari1996@gmail.com
author
Zeynab
Yazdi Sotoodeh
M.S of medical imaging, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Iran. E-mail : zeynabyazdi12@gmail.com
author
Fatemeh
shahraki
B.S. student of radiology, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Iran.
author
text
article
2018
eng
Introduction: Breast cancer is the most common cancer in women and is the second leading cause of cancer death (after lung cancer) in people throughout the world. Today, MRI is being used because of the limitations of x-ray mammography to detect breast cancer. Non-contrast sequences were associated to CE sequences in a breast MRI protocol for the sake of appraising morphologic features for lesion characterization. Two non-contrast MR methods that are mainly used for internal examination of breast tissue: proton MR spectroscopy (1H- MRS) and diffusion-weighted imaging (DWI).
In the H-MRS, the total choline peak (tCho) is used as a biomarker for the detection of malignancies. Also, the DWI protocol determines the quantity by measuring the average diffusivity and Apparent diffusion coefficient(ADC). DWI showed that cell diffusivity is correlated with cellularity and tumor aggressiveness.
Results: when looking at a clinical perspective, while MRS remained a research tool with important limitations, such as relatively long acquisition times, frequent low quality spectra, difficult standardization, and quantification of tCho tissue concentration. In contrast, the DWI has several advantages, one of its important advantages is its high sensitivity to detect breast cancer without the need for any ionizing radiation, or an isotope injection or any other contrast agent. Additionally, the acquisition time of DWI is relatively short and can be easily repeated to provide quantitative information. This technique is independent of the magnetic’s field strength. The results of two meta-analyzes revealed a overall sensitivity in the DWI of the breast 84 and 86%, and the overall specificity was 79% and 76% respectively
,These values in the MRS are between 71 to 74% and 78 to 88%, respectively40% to 60%.
Conclusion: Finally, according to studies on MRS and DWI in breast MRI, are clearly in favor of an easier and more effective use of DWI.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
37
37
https://ijmp.mums.ac.ir/article_11931_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11931
Measurement of the correlation coefficients between extracted features from CT and MR images
Fariba
Farhadi Birgani
Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Daryoush
Fatehi
Department of Medical Physics, Faculty of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran.
author
text
article
2018
eng
Introduction: Nowadays applying computer in image processing is being improved revolutionary for solving medical images deficiencies. Image features that are analysis in image processing show image information. The aim of the present study was to find correlation between CT- scan and MRI images' features.
Materials and Methods: After data acquisition, applying MATLAB image pre-processing and feature extract were performed for 1458 images of 6 patients (3 females and 3 males) referred to department of CT-scan & MRI of Golestan hospital (Ahwaz, Iran). Using SPSS the images' features were analyzed and correlation coefficients were calculated.
Results: There was significant relation between most of the features of the CT-scan images and the MRI (T1-weighted) images (p<0.01). The correlation coefficient between CT-scan images and MRI (T1-weighted) images was higher than those of CT-scan images and MRI (T2- weighted). Furthermore, the correlation coefficient between CT-scan images and MRI (T1- weighted) images was higher than those between MRI (T1-weighted) and MRI (T2- weighted) features' images. Maximum of the correlation coefficient was found between the texture features and its minimum was seen between the morphological features.
Conclusion: Conclusion: Although there is essential differences between physical basis of CT-scan and MRI as well as their clinical application, but there is a strong relationship between the extracted images' features of these twomedical diagnostic methods.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
38
38
https://ijmp.mums.ac.ir/article_11932_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11932
The Role of Dephasing in the Assessment of DMRI through Langevin Equation Approach
Elmira
Yazdani
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
Hossein
Abbasi
Department of Energy Engineering and Physics, Amirkabir University of Technology- Tehran Polytechnic, Tehran, Iran
author
text
article
2018
eng
Introduction: Diffusion Weighted Magnetic Resonance Imaging (DWMRI) provides visual contrast, depends on Brownian motion of water molecules. The diffusive behavior of water in cells alters in many disease states.
Dephasing is a factor of magnetic field inhomogeneity, heterogeneity of tissue and etc., which is associated with the signal amplitude. In a series of DWI acquisition, when diffusion sensitivity is increased, decay of the image intensity due to dephasing is observed.
There are some formulas that fit the decay phase curve of the behavior of water molecules in human tissue. Thus, if a physical model found to fit the decay observed in DWI, it would be possible to increase the sensitivity of the technique for the observation of subtle changes. Random phase variables are described using Langevin equation and Gaussian random variables by Cooke [Jennie M. Cooke, Phys. Rev, 2009].
Materials and Methods: As a step toward, it is the purpose of us to simulate the normal phase diffusion problem and its treatment by Langevin equation which is solved in a random formalism via Stratonovich algorithm for the random variables, using only the properties of the characteristic of Gaussian random variables, the classical dephasing results of Carr and Purcell, Torrey, and Stejskal and Tanner for normal diffusion.
This work is done with/without taking inertia of the nuclei into account, in which the statistics are governed by the Ornstein–Uhlenbeck process and to other more complicated situations where the nuclei move in a field of potential V(r). Moreover, signal amplitude has been analyzed in both cases.
Results: In the non-inertia approach, the stochastic results are same as classical one, however, considering inertia, signal amplitude can be achieved with higher accuracy than before. For validation, simulation results will be compared with the results of Cooke.
Conclusion: we have shown how the magnetization dephasing in DMRI may be determined by simply writing and simulating the Langevin equation for the phase random variable and then calculating its characteristic function. Hence, we have a microscopic explanation of the dephasing process in DMRI.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
39
39
https://ijmp.mums.ac.ir/article_11936_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11936
Verification of MRI MAGAT polymer gel dosimetry in clinical radiotherapy applications
Ghorban
Safaeian
Assistant Professor, Department of Radiology Technology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mohammad Taghi
Bahreyni Toossi
Professor, Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mohammad Hosein
Bahreyni Toossi
Professor, Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Shahram
Bayani
MSc in Biomedical Engineering, Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mina
Nouri
MSc medical physics, Department of Radiology Technology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
Introduction: The objective of this work is to study the ability of MRI normoxic polymer gel dosimetry system to be used to verify the calculated dose distribution, in a simple geometry, in clinical radiotherapy.
Materials and Methods: Initially, 2 liters of the normoxic MAGAT polymer gel was prepared and then poured into two cylindrical Perspex phantom (simulating a patient) and four calibration test tubes. The phantoms were then CT scanned and a dose plan was generated using the obtained CT data. The gel phantoms and the calibration test tubes were irradiated using a cobalt-60 teletherapy unit. Prior to the irradiation MRI scans of the phantom was taken to measure the background value of R2. Immediately after the irradiation, new images of the phantom and the calibration test tubes were obtained using the MRI scanner. Finally, using the MRI images in MATLAB environment R2 maps and dose maps were calculated.
Results: In radiation treatment of prostate cancer according to the three and two field techniques a homogenous absorbed dose distribution was obtained for the planning target volume (PTV) within the phantom using gel dosimeter and treatment planning systems (TPS). In the region of interest at the point center, the difference in the dose obtained from the gel dosimeter and TPS was 1.2 %. Dose sensitivity, R Square (R2) and dose resolution of MAGAT gel dosimeter also were determined and became 5.033 S-1Gy-1, .9953, .97 Gy respectively
Conclusion: In this study, two clinical treatment procedures were investigated using MRI normoxic polymer gel dosimetry and TPS. The data obtained from TPS calculations was
compared to the polymer gel dosimeter measurements and a good agreement was found.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
40
40
https://ijmp.mums.ac.ir/article_11937_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11937
Measurement of the Adsorbed Radiation Dose to Eyelens During CT Scan and Radiotherapy of Nasopharynx Cancer
Fereshteh
Zarinabadi
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
mehdi
salehi
Islamic Azad University, Tehran Center Branch
author
text
article
2018
eng
Introduction: The study of the cause of death during the last few decades has shown that death due to infectious diseases has been declining and has been rising due to noninvasive diseases, especially cancers and accidents. Cancer is considered as one of the fatal diseases, and every year, more than 10.9 million people worldwide are diagnosed with the disease.
Materials and Methods: This is an empirical study in which the ocular absorption of dose is measured due to the CT scan and radiotherapy in nasopharyngeal cancer treatments to measure the chance of cataract in nasopharyngeal cancer radiotherapy using dosimeter TLD, Gafchromic film and treatment design software on human phantom according to previous studies, and further studied with the aid of the 3-D treatment design system. This study was conducted with a medical linear accelerator in the Oncology Center of Roshana, using Varian iX linear accelerator.
Results: The value of radiation dose absorption, outside the radiation field, the average dose rate of radiation in the left eye lens is 5.76% of the total, and the average dose rate of radiation in the right eye lens is 5.68% of the total. The absorption dose of radiation by the eye, inside the radiation field, the average dose rate of radiation in the left eye lens is 10.04% of the total. The average dose rate of radiation in the right eye lens is 10.02% of the total.
Conclusion: The eye is one of the most sensitive of the body's organs versus the radiation. One of the most sensitive parts of it is the lens that can be damaged in low doses and have cataract. In this study, due to the sensitivity of the lens to ionizing radiation, we are looking for a way to prevent the excessive doses from reaching the eye, which will be measured and designed to reduce the absorption dose of the eye lens.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
41
41
https://ijmp.mums.ac.ir/article_11942_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11942
Measuring the Nitroglycerine-Induced Vasodilation in Carotid Arteries
Zahra
Taheri
MSC Student, Department of Biomechanics, Science and Research branch, Islamic Azad University, Tehran, Iran
author
Nasser
Fatouraee
Associate professor, Faculty of Biomedical Engineering, Amirkabir University of Technology, Hafez Avenue, Tehran, Iran,
author
Malikeh
Nabaei
Assistant professor, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
author
Effat
Soleimani
PاD graduated in Medical Physics from Tarbiat Modares University, Tehran, Iran
author
text
article
2018
eng
Introduction: Nitroglycerin is a fast-acting drug that rapidly dilates coronary arteries and thus increases blood flow to these vessels, and increases the blood flow through the lateral vessels to low blood areas. It also reduces both end diastolic pressure and volume of the left ventricular. However, the effect of nitroglycerin on the circulation hemodynamic is not known. Carotid artery is an artery on each side of the head and neck that supplying blood to the brain, face, scalp, skull, neck and meninges. The purpose of this study was to evaluate the influence of the Nitroglycerin on the blood velocity of the carotid artery.
Materials and Methods: Right carotid artery (common carotid artery 2 cm before the bifurcation, beginning of the internal and external carotid arteries) of 10 healthy subjects (age, 24±4 years) was scanned longitudinally with an ultrasound system (esaote Mylab 60) equipped with linear probe (4-13 MHz). Pulse wave Doppler images of blood velocity of the carotid arteries were recorded before and after taking a sublingual nitroglycerin pill. The blood velocity waveforms were extracted from sonograms over three cardiac cycles by using a custom analysis programs written in MATLAB. The effect of nitroglycerin on the carotid blood velocity was evaluated.
Results: According to the results, the carotid blood velocities changed significantly after administration the nitroglycerin. The peak systolic blood flow velocity of the CCA and ICA decreased 15% ± 9 and 20%± 16 after taking the pill, respectively. The end diastolic velocity of the blood flow in the CCA and ICA decreased 19% ± 12 and 16%± 11, respectively. The dicrotic notch of the CCA and ECA descended 24% ± 12 and 24% ± 22, respectively. There was not shown significant difference in the heart rate of the subjects before and after nitroglycerin administration.
Conclusion: According to presented results, nitroglycerin reduces both peak systolic and end diastolic blood velocity of the CCA and ICA. It seems that this hemodynamic change in the blood velocity caused by nitroglycerin might be a fast response of the carotid artery to the release of vasoactive substances such as nitric oxide (NO) from the endothelium.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
42
42
https://ijmp.mums.ac.ir/article_11943_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11943
Use of Apoptotic Biomarkers to Predict Response to Radiotherapy in Breast Cancer Patients
Hosein
Azimian
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Department of Medical Physics, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mohammad Taghi
Bahreyni Toossi
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Mahdieh
Dayyani
Reza Radiotherapy Oncology Center, Mashhad, Iran
author
Mahmoud
Mahmoudi
Immunology Research Center, Bu-Ali Research Institute, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
Introduction: To enhance radiation therapy efficiency it is crucial to implement an
individual-based treatment. The aim of present study was to identify the mechanism of intrinsic apoptosis pathway on radiosensitivity and normal tissue complications caused by the radiotherapy.
Materials and Methods: radiation-induced apoptosis in peripheral blood mononuclear cells derived from unselected breast cancer (BC) patients was examined using the relative quantitative RT-PCR. Expression levels of Bax, Bcl-2, and Bax/Bcl-2 ratio (as an in-vitro radiosensitivity index (RSI)) were examined in in-vitro irradiated (1 and 2 Gy) cells. All the patients received similar tangential irradiation of the whole breast and conventional fractionation and then, Clinical radiosensitivity (as a clinical radiosensitivity index) was determined using the acute reactions to radiotherapy of the skin according to RTOG score. All statistical analyses were performed using GraphPad Prism, version 7.01.
Results: The notable result was a significant correlation between dose-response curve slope (in-vitro RSI) and acute skin toxicity score following irradiation (clinical RSI).
Conclusion: These data suggest that Bax/Bcl-2 ratio determination before radiation therapy can be used as a potential biomarker to identify radiosensitive individuals. However, further studies are required to validate radiation-induced apoptotic biomarkers.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
42
42
https://ijmp.mums.ac.ir/article_11944_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11944
Breast Radiation Protection in Coronary Angiography
Reza
Malekzadeh
Medical Radiation Sciences Research Team, Tabriz University of Medical Sciences, Tabriz, Iran
Student research committee, Tabriz University of Medical Sciences, Tabriz, Iran
author
Parinaz
Mehnati
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Mohammad
Yousefi Sooteh
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Ali
Tarighatnia
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Yagub
Khalegi Fard
Tabriz Valiasr Hospital, Radiology and CT Scan Department, Tabriz, Iran
author
text
article
2018
eng
Introduction: Coronary angiography (CA) is an interventional diagnostic procedure to assess cardiovascular disease. CA is performed using dedicated fluoroscopic systems equipped with either flat detector or image intensifier. There is an increase in the number of CA annually. Reducing the radiation exposure in the CA is essential, especially due to high fluoroscopy time. In order to breast radiation protection in coronary angiography, the use of bismuth composite shield is a selective method. The purpose of this study was to evaluate the effectiveness of new bismuth composite shield to reduce the amount of received dose to the breast in coronary angiography.
Method and Materials: The standard female phantom and Siemens angiography system used in this research. All the procedures were carried out by one operator because factors such as the operator’s skill and experience may affect on the patient radiation exposure. The bismuth composite shields were placed on the foam with thickness of 1 cm, exactly on the back of the phantom. Dose measurements were conducted by using three thermo luminescence dosimeters (TLDs) over each breasts location with and without using bismuth shield.
Results: Breast dose was 2.45 mSv without using shield. After applying the bismuth composite shields, the recorded dose was changed to between 2.15 to 2.22 mSv. Therefore, the use of shields causes 10 % - 12% dose decline of sensitive breast tissue with acceptable imaging.
Conclusion: The results showed that the use of bismuth composite shields in the coronary angiography, leads to an acceptable decrease in breast received dose.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
44
44
https://ijmp.mums.ac.ir/article_11945_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11945
Residual DNA double strand breaks correlates with excess acute toxicity from radiotherapy
Hosein
Azimian
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Department of Medical Physics, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mohammad Taghi
Bahreyni Toossi
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Mahdieh
Dayyani
Reza Radiotherapy Oncology Center, Mashhad, Iran
author
Mahmoud
Mahmoudi
Immunology Research Center, Bu-Ali Research Institute, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
Introduction: A high risk for development of severe side effects after radiotherapy may be correlated with high cellular radiosensitivity. To enhance radiation therapy efficiency a fast and reliable in-vitro test is desirable to identify radiosensitive patients. The aim of present study was to identify the mechanism of radiation induced DNA double-strand breaks (DSBs) and DSB repair kinetics on radiosensitivity and normal tissue complications caused by the radiation therapy.
Materials and Methods: The study included 50 breast cancer patients. Blood samples (taken before radiotherapy) were irradiated in vitro with 1 and 2 Gy X-rays and The initial level of double-strand breaks (DSB) and repair kinetics analyzed by flow cytometric method of phosphorylation of histone H2A (γ-H2AX-assay) at 30 minutes, 3 and 24 hours.
All the patients received similar tangential irradiation of the whole breast and conventional fractionation and acute normal tissue reactions were assessed by Radiation Therapy Oncology Group criteria.
Results: In the in-vitro experiment repair kinetic of DSBs after 3 and 24 hours were strongly correlated with the acute skin toxicity score following irradiation (P=0.0007 and P=0.0005 respectively; Pearson's correlation test). This issue could be subject for treatment adjustment.
Conclusion: Our findings strongly suggest that the measurement of DSB by performing γ- H2AX flow cytometric analysis has the potential to be developed into a clinically useful predictive assay for distinguishing the overreactors among breast cancer patients prior to the start of radiotherapy. However, further clinical trials are required to validate these biomarkers.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
45
45
https://ijmp.mums.ac.ir/article_11946_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11946
Verification of delivered dose to the Lips carcinoma tumors with HDR brachytherapy sources: 192Ir and 60CO in an exclusive plexiglass Phantom.
Razieh
Zaghian
MSc student of Medical physic, Kermanshah university of medical science, Kermanshah, Iran
author
Abdolazim
Sedighi
Mahdieh Radiotherapy and brachytherapy charity center, Hamedan. Iran
author
Mohammad Hadi
Gholami
Mahdieh Radiotherapy and Oncology charity Centre, Hamadan. Iran
Islamic Azad University, Science and research branch, Tehran, Iran
author
Ramin
Jaberi
Tehran University of Medical Sciences · Department of Radiation Oncology, Tehran, Iran
author
text
article
2018
eng
Introduction: Brachytherapy, especially using manually after loaded Iridium-192 and Cobalt-60, can be applied as a sole treatment, as a treatment complementary to surgery, and as a local boost in combination with EBRT. The use of HDR brachytherapy catheters incorporated in removable dental molds allows repeated, highly reproducible, fractionated outpatient brachytherapy of superficial tumors without requiring repeated catheter insertion into the tumor. One of the important use of molds is controlling hyper dose sleeves. Some suitable sites for mould therapy include the scalp, lip, buccal mucosa and hard palate. In this study, we are going to dosimetry this lips mould with TLD-100 and comparing with Plexiglass exclusive phantom results.
Materials and Methods: This study has done for an early stage lip squamous cell carcinoma with mold and an exclusive lips phantom that were definitively done with using HDR brachytherapy. A customized mold was fabricated for a patient with lips superficial tumor and TLD-100 were located in the surface of mold and phantom, in which 3-4 after loading catheters were placed for passing the Iridium and Cobalt sources.
Results: The results show that we have difference about 2 percent between dose calculation for mold and phantom for Iridium and about 1.5 percent for Cobalt.
Conclusion: HDR brachytherapy using the mold technique as definitive treatment or for boosting the dose after radiotherapy, is a safe and excellent method for selected early and superficial lip cancers.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
46
46
https://ijmp.mums.ac.ir/article_11947_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11947
Synergetic Effects of the Combination of Gold Nanoparticles and Ultrasound Wave on HeLa Cells
Hadi
Akbari Zadeh
Department of Medical Physics and Medical Engineering; School of Medicine; Isfahan University of Medical Sciences; Isfahan; Iran
author
Ahmad
Shanei
Department of Medical Physics and Medical Engineering; School of Medicine; Isfahan University of Medical Sciences; Isfahan; Iran
author
Hamid
Fakhimikabir
Department of Medical Physics and Medical Engineering; School of Medicine; Isfahan University of Medical Sciences; Isfahan; Iran
author
Neda
Attaran
Applied Biophotonics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: One of the combination therapies for the treatment of cancer is ultrasound with other agents, which has received considerable attention in recent years. Ultrasound causes cavitation phenomenon that can produce some effects, such as; Reactive Oxygen Species (ROS), which results in damage to cancer cells. When a particle is in liquid, the cavitation threshold decreases due to its surface roughness. Gold nanoparticles have attracted lots of attention due to some distinct advantages including; biocompatibilities, special optical properties, good uptake by cells and high atomic number. The aim of this investigation was to evaluate combination effects of ultrasound at the presence of gold nanoparticles on the HeLa cells.
Materials and Methods: Gold nanoparticles with different concentrations (0.2, 1 and 5 μg/ml) were used. The characterizations of nanoparticles were analyzed using TEM, DLS and UV-vis. The HeLa cells were divided into 4 groups. (1) Control, (2) Gold nanoparticles, (3) Ultrasound waves alone
(4) Gold nanoparticles + ultrasound waves. The effect of nanoparticle and ultrasound waves alone as well as a combination of ultrasound waves with nanoparticles at different concentration of Gold nanoparticles and intensity of ultrasound on cell viability for 24, 48 and 72 h after the experiment were estimated by MTT assay.
Results: Results showed that the enhancement effect was depending on the intensity of ultrasound waves and the concentration of gold nanoparticles. The combination of ultrasound with gold nanoparticles did not show synergetic effects at 24 h, as opposed to 48 h and 72 h. As expected, the most synergetic effect was observed at high intensities of ultrasound wave and high concentrations of gold nanoparticles in incubation 72 h.
Conclusion: The study findings suggested that gold nanoparticles could be used as an enhancement agent in order to treat HeLa cells by ultrasound waves.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
47
47
https://ijmp.mums.ac.ir/article_11948_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11948
Unfolding X-ray spectrum in the diagnostic range using the Monte Carlo Code MCNP5
Zeinab
Shafahi
MSc, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
author
Sedigheh
Sina
samirasina@yahoo.com
author
Reza
Faghihi
PhD, Radiation Research Center, Shiraz University, Shiraz, Iran
author
text
article
2018
eng
Introduction: Unfolding X-ray spectrum is a powerful tool for quality control of X-ray tubes. Generally, the acquisition of the X-ray spectrum in diagnostic radiology departments is complicated and difficult due to high photon flux. Measurement of x ray spectra using radiation detectors could not be performed accurately, because of the pulse pile up. Therefore, indirect methods, including Compton spectrometry, are usually used to determine the X-ray spectrum in diagnostic energy range. The x-ray spectrum could be unfolded using radiation absorbing materials, proper detectors.
Materials and Methods:
The Compton scattering procedure was simulated using MCNP5 Monte Carlo code. The pulse height distributions (PHD) recorded by HPGe detector were simulated for different primary beam spectra. Then the primary spectrum was reconstructed using Tikhonov unfolding technique.
Results: The results of this study indicate that this study, the x-ray spectra for 40, 50, 80, and 100kVp were unfolded with good accuracy.
Conclusion: Tikhonov method may be effectively used in unfolding x ray spectra using Compton spectroscopy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
48
48
https://ijmp.mums.ac.ir/article_11949_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11949
Radiation- induced cognitive impairments
Soheila
Refahi
Department of Medical Physics and Physiology, Faculty of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran.
author
Hakimeh
Saadati
Department of Medical Radiation Science, School of Paramedicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Mohsen
Mohammadi
Department of Medical Radiation Science, School of Paramedicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Meysam
Siyah Mansoory
Department of Biomedical Engineering, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: Ionizing radiation is non-surgical treatment of brain tumors and metastases. Preclinical studies have showed main insights into harmful effects of radiation on the nervous system in vivo and in vitro. Cognitive impairment such as progressive memory, executive and attention performance deficits indicates a significant risk for patients experiencing conventional radiotherapy. Changes in hippocampus-dependent cognition often state radiation-induced cognitive destruction. Radiation-induced brain injury can impair neuronal, glial and vascular parts of the brain and may cause to molecular, cellular and functional alterations.
Materials and Method: In order to investigate this topic, the articles were searched for in the following bibliographic database: PubMed, Scopus, Science Direct and Google scholar and among the words used when searching were: cranial irradiation, cognitive impairment.
Results and Conclusion: To avoid of the hippocampus impairment in cranial irradiating, whereas allowing for same dose sending to the remainder of the brain, poses severe challenges given the central position and unique anatomic shape of the hippocampus. Recently, previous studies showed that the ability of modern intensity-modulated radiotherapy methods, like LINAC-based intensity-modulated radiotherapy and helical tomotherapy, to permit for the delivery of extremely conformal dose distributions.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
49
49
https://ijmp.mums.ac.ir/article_11950_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11950
Tinnitus Identification based on Brain Network Analysis of EEG Functional Connectivity
Fahimeh
Mohagheghian
Department of Medical Physics and Biomedical engineering, School of Medicine, Shahid Beheshti University of Medical Sciences (SBMU), Tehran, Iran
author
Bahador
Makkiabadi
Department of Medical Physics and Biomedical engineering, School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
author
Hamid
Jalilvand
Department of Audiology, School of Rehabilitation, Shahid Beheshti University of Medical Sciences (SBMU), Tehran, Iran
author
Hassan
Khajehpoor
Department of Medical Physics and Biomedical engineering, School of Medicine,
Research Center for Biomedical Technology and Robotics (RCBTR), Institute of Advanced Medical Technologies (IAMT), Tehran University of Medical Sciences (TUMS), Tehran, Iran
author
Nasser
Samadzadehaghdam
Department of Medical Physics and Biomedical engineering, School of Medicine,
Research Center for Biomedical Technology and Robotics (RCBTR), Institute of Advanced Medical Technologies (IAMT), Tehran University of Medical Sciences (TUMS), Tehran, Iran
author
Ehsan
Eqlimi
Department of Medical Physics and Biomedical engineering, School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
Research Center for Biomedical Technology and Robotics (RCBTR), Institute of Advanced Medical Technologies
author
Mohammad Reza
Deevband
Department of Medical Physics and Biomedical engineering, School of Medicine, Shahid Beheshti University of Medical Sciences (SBMU), Tehran, Iran
author
text
article
2018
eng
Introduction: Tinnitus known as a central nervous system disorder is correlated with specific oscillatory activities within auditory and non-auditory brain areas. Several studies in the past few years have revealed that in the most tinnitus cases, the response pattern of neurons in auditory system is changed due to auditory deafferentation, which leads to variation of the brain networks. According to neuroimaging studies, the human brain is assumed as an organization with the different degree of small-worldness, which is a concept in graph theory. Such organization is able to optimize the functional integration and segregation and therefore efficiently transfer the information among its different pairs of nodes.
Materials and Methods: In this paper, we introduce an approach to automatically distinguish tinnitus individuals from healthy controls based on whole-brain functional connectivity and network analysis. Eight participants with tinnitus and eight healthy individuals were included in the study. Resting state electroencephalographic (EEG) data were recorded using a 64-channel recorder. The functional connectivity analysis was applied to the EEG data using Weighted Phase Lag Index (WPLI) for various frequency bands in 2-44 Hz frequency range. The classification was performed on graph theoretical measures using support vector machine (SVM) as a robust classification method.
Results: Experimental results showed that the variations of connectivity patterns in tinnitus group were observed within the frontal, temporal and parietal regions. Further, promising classification performance was achieved with a high accuracy, sensitivity, and specificity in all frequency bands. The best classification performance was observed in the beta2 frequency band with accuracy, sensitivity, and specificity of 100%. The results demonstrate that four graph theory based network measures i.e. node strength, clustering coefficient, local efficiency and characteristic path length could successfully discriminate tinnitus from healthy group.
Conclusion: The results would be interpreted that the tinnitus network is more segregated but has weaker global efficiency compared to healthy group in high frequencies. In addition, tinnitus individuls presented lower segregation and greater integration relative to the healthy group in the theta frequency domain. As a conclusion, the tinnitus group shows a reduction of small-worldness as well as network integration in high-frequency bands. In general, our study provides substantial evidence that the tinnitus network can be successfully detected by consistent measures of the brain networks based on EEG functional connectivity.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
50
50
https://ijmp.mums.ac.ir/article_11951_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11951
Dosimetric pitfalls in the application of shielding disk in breast intraoperative electron radiation therapy
Mostafa
Robatjazi
Medical Physics and Radiological Sciences Department, Sabzevar University of Medical Sciences, Sabzevar, Iran
author
Hamid Reza
Baghani
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
author
Seied Rabi
Mahdavi
Medical Physics Department, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Intraoperative electron radiotherapy (IOERT) is an IORT technique in which electron beams with different nominal energies are used for irradiation of microscopic residual of tumor bed after surgery. Application of a shielding disk, which is positioned under the target volume, for protecting the normal tissues such as pectoral muscle, lung, and heart is one of the advantages of IOERT in the breast cancer treatment. A common characteristic of these disks is double-layer format; a high atomic number (Z) layer with the ability to absorb the electron beam to prevent penetration to deeper tissues and a Low-Z layer on top of the former to minimize the backscattered electrons from the lower layer. In this study, we have evaluated the misalignment effects of shielding disk on dose distribution inside the target volume and surrounding healthy tissues through EGSnrc MC Simulation.
Materials and Methods: LIAC 12 (Sordina IORT Technologies, S.p.A) is a dedicated IOERT machine that can produce electron beam energies of 6, 8, 10, 12MeV. This machine and its dedicated shielding disks which is made from 3 mm steel and 3 mm PMMA were used in this study. Machine head and employed radio-protecting disk were modeled using the BEAMnrc MC code. Some scoring planes were defined at the bottom of the applicator. Before using the phase-space files, the developed MC models were validated through comparing the Monte Carlo calculated PDDs and TDPS with those measured by ionometric dosimetry. EGSnrc C++ class library was used for simulation and calculation of the dose distribution around the shielding disk in some incorrect positions. Backscatter factor (BSF), shielding factor (SF), and percentage of leakage dose (PLD) was calculated as interested shielding parameters. In addition, some extracted parameters form differential DVH such as V100 and S-Index (Uniformity Index) were used to evaluate the dose distribution in the target.
Results: The BSFs for all correct and incorrect setups at different nominal energies varied from 1.03 to 1.11, while experimental BSF values ranged from 1.02 to 1.1. By increasing the degree of disk rotation and beam energy, the SF decreases, while the PLD would be increased. By increasing the disk rotation, V100 decrements while the S-index is increased inside the target area.
Conclusion: The analysis of uncertainties in shielding disk setup showed that the increment of disk rotation relative to applicator central axis can considerably influence the dose uncertainty inside the target volume and received dose to the organ at risks. Therefore, evaluating the treatment setup after positioning the disk and applicator through intraoperative C-arm imaging can be considered as a mandatory issue for IOERT quality assurance.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
51
51
https://ijmp.mums.ac.ir/article_11952_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11952
The study of dose gamma rays of 192Ir source on DNA single strand break (SSB) and DNA double strand break (DSB) in soft tissue phantom
Nadere
Naderi
Masters student, Faculty of Physics and Nuclear Enginering, Shahrood University of Technology , Shahrood, Iran
author
Hossein
Tavakoli-Anbaran
Facultu of Physics- University of Sahrood- Shahrood- Iran
author
text
article
2018
eng
Introduction: Passage of ionizing radiation through the organs of living creatures develops clusters of damaged nucleotides inside the DNA rounds. 192Ir Gamma source is one of the most widely used sources in brachytherapy of cervical and prostate cancer. Thus, in this research, we investigated the flux of photons and its resulting secondary electrons, the single-strand break (SSB) and double-strand break (DSB) that these electrons develop in the molecule DNA, and the dose rate in dimensions of DNA at different distances off the source in a soft tissue spherical phantom.
Materials and Methods: In this research, using Code MCNPX, we defined a soft tissue spherical phantom, where iridium 192Ir gamma source was placed in its center with 13 spherical cells with a radius of 30μm at distances off the mean free path multiplier of the average energy of this source. In the center of each of the 13 cells, cylinders with a radius of 100nm and height of 300nm were considered as approximate dimensions of the molecule DNA. Next, using this code, we calculated the flux and dose inside the cylinders. Furthermore, through the obtained electron flux, we obtained the efficiency of DNA single-strand break and double-strand break using Monte Carlo Damage Simulation (MCDS) Code.
Results: The data indicated that as the distance from the source increased, the flux of photons and electrons decreased due to interaction with the environment. Thus, the dose rate values for this source with the assumptive activity of 1mci inside the cylinders with dimensions of DNA at distances of 0.04, 0.046, 0.052, 0.058, 0.064, 0.07, 0.076, 0.1, 0.5, 1, 1.5, 2, 2.5 cm (the cells lie within these distances) were
7.56, 5.66, 4.36, 3.39, 2.65, 2.06, 1.63, 0.85, 2.8×10-2, 7.35×10-3, 3.58×10-3, 2.06×10-3, 1.41×10-3 μGy/s,
respectively. Furthermore, the probability of single-strand break(SSB) and double-strand break(DSB) also decrease due to lower flux of electrons at farther distances. It had the maximum probability in 2.5cm of 0.2% and 0.009% in single-strand and double-strand damages, respectively.
Conclusion: The results suggested that in addition to the interaction between rays and the environment and occurrence of photoelectric, Campton, and pair production, the energy of the source photons decreased, and secondary electrons were generated. Electrons are the main cause of development of break in the molecule DNA. In this regard, as the data indicated, at the farthest distance, electron flux still existed in the cylinders with dimensions of DNA, causing damage. Thus, investigation of the breaks of strand DNA and the dose resulting from the 192Ir source is important and should be taken into account in brachytherapy in order to prevent its delayed effect after the treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
52
52
https://ijmp.mums.ac.ir/article_11953_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11953
Evaluation of the use of gold nanoparticle as contrast agent in electrical impedance imaging
Mohsen
Ostovari
Assistant Professor, Department of Medical Physics and Biomedical Engineering, Shiraz University of Medical Physics, Shiraz, Iran.
author
Nader
Riahi Alam
Professor, Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Physics, Tehran, Iran.
author
Mohammad Momen
Gharibvand
M.D. Assistant Professor, Department of Radiology, school of medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mojtaba
Hoseini
PhD student, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
mansour
zabihzadeh
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Radiotherapy and Radiation Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction: Electrical Impedance Tomography (EIT) is a real time and minimal invasive imaging modality for detection of lesions in tissues even when their structures show no changes. Early detection of lesion with EIT depends on difference between electrical impedance of targeted tissue and its surroundings. Therefore, finding a contrast agent for EIT that increase this difference could improve its ability for detection of lesions in early stages. In this study, ability of gold nanoparticles (GNP) to use as EIT contrast agent was investigated.
Materials and Methods: Turkevich method was used to synthesis spherical shaped GNPs with the size of 20-25 nm. Characterization of size distribution and shape of synthesized NPs were determined by transmission electron microscopy (TEM). Two types of phantoms (chicken fat and muscle paste tissues) were prepared and their electrical impedance was measured by the 4- electrode method. These measurements were done with and without the presence of GNPs.
Results: Results show that presence of gold nanoparticles leads to descending in electrical impedance of tissues. This effect is more significant in frequencies below 1 KHz and has different values for the fat and muscle tissues. Reduction in resistive impedance is about 40.24W and1.93W
for fat and muscle tissues at frequency 1 KHz, respectively. Increase in EIT signal is a consequence of reduction in electrical impedance. Consequently, presence of GNPs enhances the EIT signal and this enhancement is different for the fat and muscle tissues.
Conclusion: As signal enhancement is different for fat and muscle tissues, gold nanoparticles could be considered as EIT contrast agent to improve detection of abnormalities at early stages.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
53
53
https://ijmp.mums.ac.ir/article_11954_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11954
Dosimetric Evaluation of Dose calculation algorithms of Monaco Treatment Planning System in the heterogeneities area
Nasim
Kavousi
Department of Medical Physics and Medical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
author
Hassan Ali
Nedaie
Radiotherapy Oncology Research Centre, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran. Nedaieha@sina.tums.ac.ir
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
author
Somayeh
Gholami
Radiotherapy Oncology Research Centre, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran. s-gholami@sina.tums.ac.ir.
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste 34151, Italy.
author
Mahbod
Esfahani
Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: In radiation therapy, the accuracy of dose calculations by a treatment planning system (TPS) is important to achieve tumor control and to spare normal tissue. Treatment planning system calculations in the heterogeneous situation may present significant inaccuracies. In this study, three different dose calculation algorithms, pencil beam (PB), collapsed cone (CC), and Monte-Carlo (MC), provided by our planning system were compared to assess their impact on the three-dimensional planning of lung region. Materials and Methods: The methodology was based on IAEA TEC-DOC 1583. The phantom resembling the human thorax are used and all tests were planned on three- dimensional treatment planning systems (TPSs) and irradiated with photon beams of 6, and 18 MV X-ray energies. The doses in specific points were measured with an ionization chamber. The differences between the measured and calculated doses were reported. This study was tested using different algorithms/inhomogeneity correction methods implemented in Monaco treatment planning system.Results: The measurements were conducted for all test case datasets for two photon beam energies and calculation algorithms. The deviation between the measured and calculated values for all test cases made with advanced algorithms (MC and CC) were within the agreement criteria, while the larger deviations were observed for PB algorithm. Subsequently, there were discovered dose differences greater than 20% for some simple algorithms and high energy X-ray beams. The number of measurements with results outside the agreement criteria increased with the increase of the beam energy and decreased with TPS calculation algorithm sophistication. Also, a few errors in the basic dosimetry data in TPS were detected and corrected.Conclusion: Differences were found when comparing the calculation algorithms. The PB algorithm actually overestimated the dose compared with those calculated by the CC and MC algorithms. The MC algorithm showed better accuracy than the other algorithms. Therefore advanced dose calculation algorithms are suitable and should be used in clinical practice
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
54
54
https://ijmp.mums.ac.ir/article_11955_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11955
Effect of the combination of 6 MeV radiotherapy with hyperthermia and gold nanoparticles on the MCF-7 breast cancer cells
Bijan
Hashemi
Associate Professor, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Akram
Mohammadi
Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Seied Rabie
Mahdavi
Associate Professor, Department of Medical Physics, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Combining radiotherapy as one of the main modalities used for cancer treatment with other modalities such as hyperthermia has recently played a special role in reducing side effects and improving treatment outcomes. In addition, Gold nanoparticles (GNPs) have also attracted attention as suitable clinical agents for enhancing the effect of radiotherapy in treating various cancers. The purpose of this study was to investigate the effect of combination of radiotherapy with both of the hyperthermia and GNPs for the treatment of MCF-7 breast cancer cells.
Materials and Methods: We evaluated the cell death of MCF-7 breast cancer cells when treated with 6 MeV radiation therapy and 13.56 MHz capacitive radiofrequency hyperthermia in the presence of 20 nm GNPs with the lowest toxicity concentration. Initially, the cells were incubated with 20 mg/L GNPs for 24 hours. Then, they were exposed to RF hyperthermia with a power of 200 W for 15 min. Afterward, they were exposed to 6 MeV electron beam produced by a linear accelerator with a dose of 2Gy.
Results: Our primary results showed that the presence of GNPs in the cancer cells and also thermal sensitizations provided by hyperthermia increases the rate of the MCF7 cancerous cell death and also the therapeutic efficiency.
Conclusion: The combination of the two sensitizing modalities, i.e. radiofrequency hyperthermia and GNPs could be regarded for better delivery of the highest dose to the target while maintaining the lowest dose to adjustments normal organs/tissues as risk in the future. However this would require more in vivo animal studies as well as clinical human investigations.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
55
55
https://ijmp.mums.ac.ir/article_11958_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11958
Investigated the effect of near inferared laser on Folliculogenesis cycle and compared with Colomiphene effects in vivo condition in rat’s ovary
Paria
Naseri
Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Stem cell research Centre, Tabriz University of Medical Sciences, Tabriz, Iran
author
Seyed Hosein
Rasta
Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Stem cell research Centre, Tabriz University of Medical Sciences, Tabriz, Iran
School of Medical Sciences, University of Aberdeen, Aberdeen, UK
author
Alireza
Ali Hemmati
Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Stem cell research Centre, Tabriz University of Medical Sciences, Tabriz, Iran
author
text
article
2018
eng
Introduction: Any disruption in Folliculogenesis cycle (FC) as a produces oocyte function, leads to ovulation diseases, like poly cystic ovarian syndrome (PCOS). Although, there have not been found any definite treatment for PCOS, there are some temporary methods to treat it. That’s including drug, surgery and also lasers as complementary. In addition, these methods not only don’t have short period treatment but also they increase the risk of woman’s breast cancer. In a world, this research investigated the photo-bio stimulation effect of low-level laser (180nm wavelength) on ovarian FC in the Rat’s ovary by Diode lasers as independent method.
Materials and Methods: In this study 21 female rats with the average age of 9 weeks in the 150-250 gr weight were used. The subjects were assigned to three groups: control (CT) clomiphene drug (D) and near infrared laser (NIRL), seven rats in each group. Afterwards, for 48 days in NIRL group, the rats received laser (5j/cm2) on estrous cycle. In D group, they received clomiphene drug (1µ/g in 1cc water solution). At the end, we anesthetized the animals and removed their ovary tissue. Henceforth, we investigated the lasers effects and compared with clomiphene. This protocol approved by Ethics and Research Committee of Tabriz university medical science (code number: TBZMED.REC.1394.238). Also this study’s results analyzed with statistical application as well.
Results: Laser is the main catalyst to increase different follicles (DF) producing to complement FC. The increase of DF significant compared with D and CT groups. It’s significant in D group to compare with CT. But it’s ratio in NIRL group was rather than D.
Conclusion: So, laser increase ovarian activity to produce DF. This result certainly can be used in future studies for finding a cure for negligent of ovary and treated diseases caused by ovarian negligence like PCOS. Finally, this study indicates that lasers can be used autonomously for treat, without any medical and surgical intervention.
Acknowledgments:
Hereby the authors express their gratitude to Eshrat khah and Musavi, Doctoral candidates, at the University of Tabriz for measuring hormone level; Abed Ellahi of the anatomy group, Tabriz University and Pedram Hamidi, master candidate at the Shahrood University, for designing rat restrainer and processing results by the SPSS software.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
56
56
https://ijmp.mums.ac.ir/article_11959_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11959
Radiosensitization of breast cancer cells using AS1411 aptamer-conjugated gold nanoparticles
Bijan
Hashemi
Associate Professor, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Somayeh Sadat
Mehrnia
Graduate, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Seyed Javad
Mowla
Professor, Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
author
Azim
Arbabi
Professor, Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
author
Maryam
Nikkhah
Associate Professor, Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
author
text
article
2018
eng
Introduction: A main choice for cancer treatment is radiotherapy. But, the radiotherapy disadvantage is damages caused by radiation given to normal tissues/organs surrounding cancer. One way to avoid this is via increasing radiosensitization of cancer cells. Gold nanoparticles (GNPs) have shown sensitizing effect on cancer cells by enhancing their absorbed dose. Unlike earlier delivery techniques developed for nanotherapeutics, active targeting can achieve specific effect and higher uptake of GNPs in tumors while leave healthy cells untouched and consequently improve the therapeutic index. To achieve active targeting, GNPs should be equipped with functional ligands which can recognize and adhere to the receptors of cancer cells. Aptamers are small DNA-molecule/RNA-fragments with high specificity and affinity towards target molecules. AS1411 aptamer can specifically bind to over-expressed nucleolin on the membrane of tumor cells including breast cancer. This aptamer is capable to enter cancer cells through specific ligand–receptor interaction. Greater uptake of GNPs by cells may induce increased radiation effects. Cancer stem cells are a small population of cells within a tumor capable for self-renewal and differentiation into various cell types.
Materials and Methods: We hypothesized that conjugation of GNPs with AS1411 (AS1411/GNPs) could increase GNPs-mediated radiosensitization in breast cancer cells. We hypothesized that AS1411/GNPs would radiosensitize breast cancer stem/progenitor cells grown to three- dimensional (3D) mammospheres. Cytotoxicity studies of the GNPs and AS1411/GNPs were done on two different cancer cell lines of MCF-7 and MDA-MB-231 with MTT assay. Atomic absorption spectroscopy (AAS) confirmed the cellular uptake of particles. Radiosensitizing effect of GNPs and AS1411/GNPs on MDA-MB 231 and MCF- 7 cells assessed by clonogenic assay.
Results: Clonogenic survival data revealed that AS1411/GNPs at 12.5 mg/L results in radiosensitization of breast cancer cells. Mammosphere of MCF-7 was more resistant than their monolayer counterparts.
Conclusion: The combination of the sensitizing GNPs with the AS14411 aptamer can be regarded for improved treatment of breast cancer cells especially for the mammosphere MCF-7 cancer cells mimicking cancerous tumors.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
57
57
https://ijmp.mums.ac.ir/article_11960_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11960
Improvement ability of EIT for Thermal monitoring during Thermal Therapy by gold nanoparticles
Mohsen
Ostovari
Assistant Professor, Department of Medical Physics and Biomedical Engineering, Shiraz University of Medical Sciences, Shiraz, Iran.
author
Nader
Riahi Alam
Professor, Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
author
Mohammad Momen
Gharibvand
M.D. Assistant Professor, Department of Radiology, school of medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Amir
Danyaei
Assistant Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mansour
Zabihzadeh
Nanotechnology Research Center, Faculty of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Clinical Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction: To prevention the healthy tissues from irreversible damages, monitoring the temperature variation of healthy tissues is critical parameter during thermal therapies. Electrical impedance tomography (EIT) is considered as a real time imaging modality for monitoring the temperature but researches show that it suffers from low temperature resolution. In this study using of gold nanoparticles(GNPs) to increase the EIT signal variation due to change in temperature of tissues was studied and improvement of its temperature resolution was surveyed.
Materials and Methods: Spherical GNPs with size of 20-25 nm were synthesized with Turkevich method. Size distribution and shape of these NPs was characterized by transmission electron microscopy (TEM). EI of muscle and fat tissues at different temperatures were measured and compared to their EI at presence of GNPs.
Results: EI of tissues decrease (electrical conductance increase) as their temperature increase and GNPs cause to intensify this phenomenon. Increase in specific conductance of fat and muscle
tissues at 360 C were 3.80´10-3 S m and 8.59´10-2 S m, respectively. These values were
15.1% and 13.2% for fat and muscle tissues, respectively.
Conclusion: Presence of GNPs could lead to increase the variation of EIT signal intensity due to change of temperature. Therefore, considering the temperature changes followed to use of GNPs in thermal treatment is recommended.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
58
58
https://ijmp.mums.ac.ir/article_11961_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11961
A prospective radiobiological study of acute esophagitis and swallowing dysfunction in head-and-neck radiotherapy
Elahe
Fathipour
Department of Radiology& Radiobiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad Amin
Mosleh-Shirazi
Department of Radiology& Radiobiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mansour
Ansari
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad
Mohammadianpanah
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad Reza
Sasani
Medical Imaging Research Center and Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Pyman
Jafari
Department of Biostatistics, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction: Esophagitis is one of the main causes of swallowing dysfunction after radiation therapy (RT) for head and neck cancer (HNC).It significantly affects patients’ quality of life as well as having a potentially negative impact on their long term survival. However, little has been investigated on the dose-response and normal tissue complication probability (NTCP) of esophagitis in the cervical esophagus (CE), although it is often at risk in neck irradiation. The aim of this study was to investigate the incidence and dose-response relation for acute esophagitis in HNC patients undergoing 3D conformal RT.
Materials and Methods: This prospective study consisted of 50 HNC patients. The main studied endpoint was grade 2 or higher acute esophagitis according to the Common Terminology Criteria for Adverse
Events v.4 scoring criteria within 9 weeks after the start of RT, assessed using the EORTC
QLQ-H&N-35 questionnaire. The mean dose and dose-volume parameters were analyzed for
CE and eight other swallowing-related structures including: superior, middle and inferior
pharyngeal constrictor muscles (SPCM, MPCM and IPCM, respectively), esophagus inlet
muscle (EIM), supraglottic larynx (SGL), base of tongue (BT), glottic larynx and
cricopharyngeal muscle. Then, due to the lack of model parameters for acute esophagitis in
the CE, the ability of four sets of LKB model parameters available for predicting the NTCP of
this endpoint for middle and lower esophagus was evaluated based on the mean CE dose in
these patients.
Results: Forty three patients (86%) experienced grade ≥ 2 acute esophagitis in the follow-up period (no grades 4 or 5). The V30 of the SPCM, V30-V40 of the MPCM, V50 of the EIM, V40-V55 of the CE, V60 of the BT, and V20-V40 of the SGL, and the mean doses of these six structures, correlated with swallowing dysfunction. The mean dose to the CE was the most significant parameter. The LKB model parameters TD50= 47 Gy, m= 0.36, n= 0.069 showed the current best fit to the observed NTCP.
Conclusion: The mean dose and V40-V55 to the CE were significantly associated with swallowing dysfunction. The high number of patients who experienced swallowing complications in this study adds evidence to the necessity of advanced treatment planning and delivery techniques that offer dose optimization to reduce esophagitis in HNC RT. Better LKB model parameters for predicting swallowing dysfunction due to CE dose are also required.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
59
59
https://ijmp.mums.ac.ir/article_11964_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11964
Comparison of I-131, I-123 Absorbed Dose and Tc-99m in Thyroid Scanning Using MCNP Code in ORNL-MIRD Phantom
Fatemeh
Hasanpour
MSc student of nuclear physics, Faculty of science, University of Guilan, Rasht, Iran
author
Ali
Rouhi sesari
Physics department, K.N Toosi University of Technology, Tehran, Iran
author
Alireza
Sadremomtaz
Physics department, Faculty of science, University of Guilan, Rasht, Iran
author
text
article
2018
eng
Introduction: Thyroid cancer is at the ninth from ten of common malignant cancer. A man has higher risk to get Thyroid cancer that a woman has. This organ is lain near human neck. The use of radioactive I-131, I-123 and Tc-99m for diagnosis of thyroid cancer has a risk where other organs around Thyroid will accept dose of radiation. One of the risks is large dose which is accepted by brain, skin and lung. Large dose accepted those organs will make a high defect at those organs. To reduce that problem, we have to know the problem dose which is accepted by cell cancer and the organs. One of is to make a simulation of interaction of radiation particle with organ. The simulation used to determine the intermine the interaction of radiation particles and matter is a Monte Carlo method. One of Monte Carlo software is MCNPX (Monte Carlo N-Particle) made by a team from Los Alamos National Laboratory. It can simulate particles interaction with real situation. The use of Monte Carlo in radiation transport is an effective way to predict absorbed dose in an organ. According to Krstic, MCNP can be used to simulate dose in organs by Prostate Brachytherapy showed that MCNP calculation can determine dose in organ. The use of a well-supported radiation transport code such as MCNP with knowledge of patient anatomy will result in a significant improvement in the accuracy of dose calculations. This study simulates Thyroid cancer with Male and Female ORNL- MIRD phantom and uses I-131, I-123 and Tc-99m radioactive which are distributed with MCNPX program.
Materials and Methods: Materials used in this research were ORNL-MIRD database geometry. The exterior of phantom has approximately the form of the human body. . The simulation used to determine the interaction of radiation particles and matter is a Monte Carlo method. One of Monte Carlo software is MCNPX made by a team from Los Alamos National Laboratory. It can simulate particles interaction with real situation.
Results: MCNP simulation simulates radiation process to obtain dose in organ. The absorbed dose in Thyroid and other organs increased every rising activity of I-123,I-131 and Tc-99m used, but the absorbed dose in other organs was less than in Thyroid.
Conclusion: The calculation results was obtained that absorbed dose in Thyroid would increase by rise of I-123, I-131 and Tc-99m activity but absorbed dose in other organs around Thyroid such as Brain, Lung and Skin was less than in Thyroid. The maximum of absorbed dose in Thyroid was at 1 mci activity of I-131. However, the effect of 1 mci in other organs around Thyroid was still less that it was not really influential for the organs.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
60
60
https://ijmp.mums.ac.ir/article_11967_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.11967
Hadron Therapy in Iran: Patient Indication Estimation and Challenges Ahead
Mohammad Amin
Hosseini
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad Amin
Mosleh-Shirazi
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad
Zare-Bandeamiri
Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad
Mohammadianpanah
Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
Colorectal Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction: Radiotherapy with heavy charged particles such as protons and carbon ions (hadron therapy) has been recognized as an advanced technique for the treatment of various cancers. For some indications such as pediatric and radio-resistant tumors, it is considered the preferred method. However, despite its remarkable benefits, development of hadron therapy centers in the world has always been subject to major constraints due to a number of reasons including the high costs of constructing and maintaining the centers, the need for strong infrastructures, and the lack of adequate research on the estimation of the number of patients eligible for utilizing this technique. Therefore, this study aimed to investigate the initial estimation of the number of patients eligible for hadron therapy in the Fars Province and Iran as a whole. Materials and Methods: In the absence of comprehensive national cancer registry data, the information for the initial estimation of the number of patients residing in the province were collected from the medical records of the patients who were treated at the Radiotherapy Department of Shiraz Namazi Hospital in 2014. First, the patients’ demographic data (place of residence, age, and sex) as well as the type of cancer were extracted according to the patients’ pathology reports. Only the patients residing in Fars were selected. Then, all of the resulting indications were classified based on the methodology proposed in previous studies, and by applying separate coefficients on each, all the indications suitable for the hadron therapy in Fars were determined. Subsequently, by applying a coefficient of 16.4 (the ratio of the total population of the country to that of the Fars Province in 2014), the number of the patients eligible for hadron therapy in the whole country was calculated. Results: Of the total 2,932 cases studied, 1536 patients were residing in Fars, 22.9% of whom were eligible for hadron therapy. Accordingly, the total number of patients in the country was estimated to be 5765 cases/year. Considering similar studies from other countries with such clinics, at least two hadron therapy centers are needed for treating the eligible estimated population. Conclusion: The analysis performed in this study (solely considering patient numbers and treatment indications) suggests that at least two geographically-spread hadron therapy centers are indicated (covering two northern and southern regions of similar populations). The limitations in having access to accurate patient data and the insufficiencies in the national cancer registry system hinders accurate estimations, which potentially lead to underestimation of patient numbers. Also, other economic factors, experience of other countries and expert advice should be considered. The need for extensive cost-benefit studies versus lower-cost radiotherapy equipment before investment is emphasized.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
61
61
https://ijmp.mums.ac.ir/article_12078_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12078
Organ dose in kidney imaging with contrast media
Parinaz
Mehnati
Associate Professor, Department of Medical Physics, Faculty of Medicine, Tabriz, Iran.
author
Samad
Ghasemi
M.S. student of Medical Physics, Department of Medical Physics, Faculty of Medicine, Tabriz, Iran.
author
Mohammad Reza
Ardalan
Professor of Nephrology, Kidney research center, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Fariba
Mahmood Poor
MD-MPH, Kidney research center, Tabriz University of Medical Sciences, Tabriz, Iran.
author
text
article
2018
eng
Introduction:Intravenous urography (IVU) test includes high number of images and extended imaging size. These make IVU as a diagnostic method with high absorbed doses by sensitive organs such as intestine and gonads in pelvic-abdominal area. In this study absorbed doses of pelvic-abdomen sensitive organs such as Adrenal, Bladder, Colon and Gonads in IVU test. Method and Materials: Demographic properties of one hundred patients’ who referred for kidney imaging was recorded during one year. Exposure factors were recorded for each patient during IVU test. In this study CALDose software used for Entrance Surface Air Kerma (ESAK) recording. Organ dose was calculated by conversion coefficient of organ × ESAK Results: The age averages of men and women were 52 and 53 years, respectively. The average ESAK dose for patients in one step of each IVU examination was 3.8 mGy. The organ dose of Adrenal, Bladder, Colon and Gonads 1.8, 1.8, 7.0 and 2.0, respectively. Conclusion: These results showed that IVU processing in clouding higher dose to sensitive organs and selection of correct exposures factors can reduce organ dose.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
62
62
https://ijmp.mums.ac.ir/article_12079_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12079
Measuring midline dose without build-up cap for patients with brain tumor undergoing 15MV external radiotherapy by using EBT3 Gafchromic film
Bijan
Hashemi
Ph.D., Associate Professor, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Seyed Masoud
Rezaeijo
M.Sc. Graduate, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Seied Rabie
Mahdavi
Ph.D., Associate Professor, Department of Medical Physics, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: The Purpose of this study has been measuring midline dose for the patients undergoing brain radiotherapy without any need to build-up cap. Materials and Methods: The study was performed on 28 patients with brain tumor undergoing 15 MV radiotherapy by a Siemens LINAC. To estimate the midline dose, the entrance and exit doses were calculated by a conversion ratio. The conversion ratio was determined as the ratio of the measured dose by EBT3 Gafchromic film at the phantom surface to that measured by an ionization chamber at the depth of 3 and 12 cm. Then, the midline and exit transmission curves were obtained in a solid water phantom for various irradiation conditions with and without a 30-degree wedge for various field sizes of 5×5, 10×10 and 15×15 cm2 and at various SSDs including 80, 90 and 100 cm at various depths ranged from 6 to 22 cm by a 0.6 CC ionization chamber. Eventually, to measure the midline dose, we used both of the midline transmission and arithmetic mean algorithms. Results: The mean and standard deviation of the whole sample for midline transmission algorithm were -3% and 4.52% and for that of arithmetic mean algorithm -2.97% and 4.3%, respectively. However, for 9 patients, more than 5% error was noted in estimated midline doses. Conclusion: A new method was developed for measuring the midline dose without any need to use the build-up cap. The main advantage of the developed method is that there is no disruption in the dose reached to the treatment volume.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
63
63
https://ijmp.mums.ac.ir/article_12080_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12080
Assessment of The Relation Between Energy Of Primary Protons And Undesired Neutron Dose During Proton Therapy By Monte Carlo Method
Kosar
safari
MSc student of nuclear physics, Facultry of science, University of Guilan, Rasht, Iran
author
text
article
2018
eng
Introduction: High-energy beams of protons offer significant advantages for the treatment of deepseated local tumors. Their physical depth-dose distribution in tissue is characterized by a small entrance dose and a distinct maximum -Bragg peak- near the end of range with a sharp fall-off at the distal edge. Alongside its advantages there are some point that they need to meticulous attention. Producing dose due to secondary particles is one of the important challenges in proton therapy.
Materials and Methods: In the first stage the head was simulated by a cylindrical water phantom with length of 19cm and diameter of 19cm with 0.5 cm thickness of plexiglass. Then proton characteristics such as depth-dose distribution were investigated. In the next stage to evaluate the effect of variation of target density on depth-dose distribution, density of phantom materials varied. Increasing tissue density by 5% proton dose was decreased. Then a spherical tumor with diameter of 1cm in the phantom was considered and calculation of dose performed in the tumor and phantom. We have applied the MCNPX version of 2.6.0 code for proton beam energies ranging from 150 to 160 MeV, with steps of 1MeV, to obtain the ionization values, which are related to the cell damage or dose, in the target. MCNPX code is a general purpose radiation transport simulation code which is capable to simulate proton beams. This code requires an input file data that defines the geometry, the physical parameters and the tallies of the simulated problem.
Results: results have good agreement with results of TRIM package. Protons with 160 MeV energy have bragg peak in 17.1 cm and it has value of 1.237e-11 Gy/ source particles . we found that, for each 5 MeV increase for energy of protons, dose increase about 4.28%. after calculating dose for 11 steps between 150 and 160 MeV, proton by 153 MeV energy have the best dose distribution because it has maximum dose in tumor area and minimum dose for healthy tissue. Again simulation with TRIM code confirm this result. And also we found secondary neutron dose was found to be 100 orders lower than primary proton dose. Further providing evidence that secondary dose is relatively small in proton therapy.
Conclusion: Energy of entranced protons has significant effect on production of neutrons so it is helpful to use optimum energy for proton therapy especially for sensitive part of the body like brain, because neutron dose during proton therapy may increase the risk of metastases cancer.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
64
64
https://ijmp.mums.ac.ir/article_12081_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12081
Evaluation of the simultaneous presence of aluminum chloride and 50 Hz magnetic field on the antioxidant capacity of blood hemoglobin and plasma in rat’s protective role of Myrtus plant
Mohamad Reza
Bayatiani
Ph. D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran.
author
Fatemeh
Seif
Ph. D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran.
author
Hadi
Ansarihadipour
Ph. D of Biochemestry. Department of Biochemistry and Genetics, School of Medicine, Arak University of Medical Sciences, Arak, Iran
author
Ghasem
Habibi
Medicine Student, Hamedan University of Medical Sciences, Hamedan, Iran.
author
text
article
2018
eng
Introduction: Physical factors such as electromagnetic fields and chemical agents such as aluminum compounds can act as oxidative stress inducer. In the present study synergistic and toxic effects of aluminum in the presence of an alternating electromagnetic field is investigated. In order to make the protection the extract of Myrtus Communis was used
Materials and Methods: In this experiment, there were 6 groups as follows: 1) control group 2) Aluminum chloride (8mg / kg) 3) the magnetic field (50 Hz and 1mT) 4) Aluminum chloride + magnetic field 5) Aluminum chloride + extract (1.5 mg/ kg) 6) A group that only receives the extract.7) magnetic field + aluminum chloride + extract. aluminum choloride was given intraperitoneally. The extract of Myrtus Communis (1.5 mg / kg) 2 hours before the injection by gavage was given to them. After experiments the blood samples were collected then Changes in the structure of hemoglobin, FRAP and MDA tests were performed
Results: Exposure to electromagnetic field and aluminum chloride individually can reduce FRAP values (90.47±2.39, 73.36±1.89, 76.45±1.36, 68.27±1.32, 82.52±1.01, 80.22±1.44) (P <0.01) and increase in the amount of MDA(18.13±0.67, 12.25±0.19, 14.62±0.37, 8.54±0.57, 13.51±0.75, 12.38±0.35) (P <0.01). in case of aluminum chloride and magnetic field the synergistic effects of oxidative stress was enhanced (P <0.01). In all the above cases, the herbal extract can improve significantly the harmful effects (P <0.01)
Conclusion: Each of Electromagnetic Fields and aluminum chloride can act as oxidizing agents, The combined effect of these two physical and chemical factors can act synergical and Cause biological damage.Treatment with extract Myrtus Communis can provide the protection against oxidative damage.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
65
65
https://ijmp.mums.ac.ir/article_12082_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12082
Pulsed electromagnetic field at frequency and intensity resembling potassium ion cyclotron resonance selectively impairs breast cancer cell through apoptosis
Mansoureh
Zarei
Medical physics department, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Ali
Yadollahpour
Medical physics department, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Farzin
Moradi
The deputy of research and technology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction: Breast cancer (BC) is the most common women cancer worldwide. Radiotherapy and chemotherapy are the two common treatment options but these techniques suffer low selectivity and adverse effects on surrounding normal tissues. Non- ionizing pulsed electromagnetic fields (PEMFs) in ultra-narrow band frequency and intensity have shown anticancer effects. Changing potassium ion (K+) activities is a pivotal mechanism regulating different physiological functions and cell proliferation. PEMFs at ion cyclotron resonance (ICR) frequency tuned to main biological ions such as K+ can modulate cell cycle and proliferation. The present study aims to comparatively investigate the effects of PEMF at frequency and intensity resembling K+-ICR condition (50 Hz, 127.2 µT) on cancerous (MCF-7) and normal breast (MCF-10) cells. In addition, the mechanisms of actions of the PEMF were assessed using MTT and flow cytometry assessments.
Materials and Methods: The both cell lines had been treated by PEMF (50 HZ, 127.2 µT) for 24 and 48 h in a special purpose built PEMF generator that generated uniform magnetic fields resembling the K+-ICR condition at 50 Hz and intensity of 127.2 µT. The cell viability and apoptosis percentage were respectively assessed using MTT assay and flow cytometry with Annexin V apoptosis protocol.
Results: In the PEMF (50 HZ and 127.2 µT) with 24 h exposure time, viability percentage of cancer cells significantly decreased compared to the normal cells (74.79% versus 90%) (P=0.007). Increasing the exposure time from 24 h to 48 h did not significantly alter the MCF- 10 cells proliferation (90% to 91.5%)(P=0.97). Contrary, the mortality rate in MCF-7 cell line significantly increased by 23.49% (P=0.0006). In the 48 h exposure time, late and early apoptosis percentage significantly increased in MCF-7 cells, compared to the control cells (9.96 ± 0.024 Versus 4.03 ± 0.025) (P= 0.001)
Conclusion: PEMF with K+-ICR condition selectively impairs breast cancer cell viability while did not affect normal cell line. Induction of apoptosis seems the main mechanism of actions of cell death in the cancerous breast cell line under PEMF exposure. These data suggest that PEMF tuned to K+-ICR may be a potential BC treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
66
66
https://ijmp.mums.ac.ir/article_12083_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12083
The Correlation between Cell Phone over Use and Aggression
Mohamad Reza
Bayatiani
Ph. D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran.
author
Fatemeh
Seif
Ph. D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran.
author
text
article
2018
eng
Introduction: Today concerns about the somatic and mental-emotional effects of exposure to electromagnetic waves have been raised. Although early thermal effects can not be attributed to these waves, It is necessary to investigate the long-term and side effects of these waves. One of the devices that has the most connection with electromagnetic waves is cell phones. In the present study, the correlation between excessive use of mobile phones and agression in students was investigated.
Materials and Methods: This study was conducted with the participation of 810 students of Arak University of Medical Sciences. At first, demographic information was obtained, then the mobile phone dependence was measured by the use of "Cell Phone Over-Use Scale (COS)". AGQ questionnaire was used to measure aggression, in which four subscales of physical aggression (PA), verbal aggression (VA), anger (A), and hostility (H) were studied. The survey of both questionnaires was based on Likert scale. Data were analyzed using SPSS20 software, Chi-Square, t-test and Pearson correlation coefficient at a significant level of 0.05.
Results: The average score of the COS and physical aggression (PA), verbal aggression (VA), anger (A), and hostility (H), was (54.10 ± 16.10), (18.23 ± 3.12), (12.56 ± 3.65), (17.45 ± 5.26), (14.9
± 4.42) Which had no significant difference between men and women(p≥0.05). Also, Pearson correlation test showed that there is a positive and significant relationship between all AGQ components and excessive use (P <0.01).
Conclusion: However, Thermal effects for 900 Mhz electromagnetic waves can not be considered. Two important factors that can be considered in related research include the late effects and mental-psychological effects. In this research, excessive use of mobile phones has been shown to have a direct positive correlation with the increase in agression and its associated components.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
67
67
https://ijmp.mums.ac.ir/article_12086_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12086
A feasibility study on the use of MV-CBCT images for urgent palliative treatment planning
Mehdi
Jamali
M.Sc., Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Mehdi
Momennezhad
PhD, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Fateme
Shahedi
M.Sc., Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran.
author
Shahrokh
Naseri
PhD, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
text
article
2018
eng
Introduction: The application of 3D volumetric imaging modalities in treatment planning of radiation therapy can provide more precisely define tumor localization, and computed tomography (CT) is the most common accepted method for treatment planning. Given the lack of a CT scanner stationed in all radiotherapy departments and equipping most of the medical linear accelerators with only electronics portal imaging device (EPID) device, the use of this technology for megavoltage cone-beam computed tomography (MV-CBCT) imaging in such cases as urgent palliative radiotherapy treatments, leads to precise localization of the tumor and increases the accuracy of the beam sent to the target area. Since MV-CBCT imaging is possible using EPID, this study is aimed at conducting MV-CBCT and investigating the possibility of using these images in the treatment planning of the radiation therapy.
Materials and Methods: Initially, the projection data of an anthropomorphic head phantom was acquired at 3o increments for a 360° of gantry rotation around the patient, and then the 2D projections were reconstructed with Feldkamp cone-beam algorithm. The intensity-to- electron-density calibration was performed for MV-CBCT images to converts the reconstructed gray-level intensity of each image voxel into an electron density value. The reconstructed MV-CBCT images were sent to the treatment planning software, and after the registration with KVCT images, two independent plans were generated on the both CT datasets. Finally, the dose volume histogram (DVH) of the anatomical targets contoured with MV-CBCT was compared to DVH of the same targets contoured with KVCT images.
Results: There was a high level of agreement between the MV-CBCT and KVCT plans with the anatomical structures of the skull as the target. The shift between the co-ordinate positions of the anatomical points identified on the MV-CBCT from the reference planning CT points, and the calculated dose based on the both CT datasets have an acceptable level of agreement.
Conclusion: The results of this study show that MV-CBCT images could be effective for treatment planning modality include single fraction palliative treatment. However, low contrast resolution and extended scan acquisition time are the two main limiting factor that eliminate this imaging modality only for palliative treatments at easily distinguishable area, such as brain.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
68
68
https://ijmp.mums.ac.ir/article_12087_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12087
An easy method to create the better representative of patients with various body morphologies
Keyhandokht
Karimi Shahri
Physics Department, Faculty of Science, University Of Birjand, 9717851367Birjand, Iran
author
text
article
2018
eng
Introduction: In recent years, there has been increasing demand for personalized anatomy modeling for medical applications, because the influence of phantoms on the quality of treatments and precision dosimetry has been specified. Phantoms have many applications on medical such as treatment planning, diagnostic imaging, clinical radiological exposure simulation, and biomechanics analysis. The first generation of phantoms was based upon mathematical expressions describing idealized body organs. The second generation was based on three-dimensional images of individuals (CT or MRI images), they offer a more realistic anatomy. This generation was named voxel phantoms. Unfortunately, these phantoms are often limited to a single reference size, which often may not be representative of the patient population at large because they are in the different weight percentile. On the other hand, the construction of specific- patient phantoms is time -consuming and costly. The aim of this study by adding muscle and adipose tissues to a reference adult ORNL phantom torso (50th percentile) was built 65th, 75th, 85th and 95th weight percentiles. To ensure the method, results were acquired for VIPMAN and NORMAN voxel phantoms. The obtained results were compared with that of reported in previous study.
Materials and Methods: The difference between the thickness of the torso muscle and adipose tissues between ORNL with VIPMAN, NORMAN and weight percentiles above the 50th percentile was determined then its equivalent the muscle and adipose tissues were added to the ORNL torso. By appending these layers, the skin and breasts positions were altered. The front and back skin of the torso was also separated and was simulated by two distinct cells in the Monte Carlo code since the tissues added to the front and back of the torso were not the same. Simulations were performed using MCNPX2.4.0 Monte Carlo code for photons with energies 10keV to 10 MeV for anterior-posterior (AP), posterior-anterior (PA), left-lateral (LLAT) and right-lateral (RLAT) irradiation geometries. ENDF/B-VII cross section library was used for calculations. Kerma approximation was applied for energies lower than 500 keV and electron transport was done for energies above 500 keV. Effective dose was calculated using the radiation and tissue weighting factors (wR and wT) from the recommendation of ICRP publication 103.
Results: Differences are reported as the mean relative difference of effective dose and ± SD. The greatest differences for VIPMAN and NORMAN was observed in PA (23.80±12.30) and RLAT (8.20±12.10) respectively. These differences were decreased to 12.10±9.10 and 4.90±2.10 for VIPMAN and NORMAN after adding extra tissues to the ORNL torso. According to results there is a satisfactory agreement between the ORNL, VIPMAN and NORMAN after the addition of the appropriate thickness to the back and front of ORNL torso. Comparisons between different weight percentiles indicate that effective dose was decreased with increasing the weight percentile, so that the mean relative difference of effective dose in 65th, 75th, 85th and 95th with 50th percentile is 15.00±12.04, 18.17±13.05, 20.00±13.93and 24.93±15.17 respectively for AP. As results are shown with increasing percentile, differences and SD were significantly increased.
Conclusion: The results show that by adding extra tissues to an existing 50th percentile can be created other weight percentile. This method can easily be used to expand the phantoms library in order to improve the treatment planning and diagnostic procedure.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
69
69
https://ijmp.mums.ac.ir/article_12088_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12088
Radiation protection properties of Myrtus communis against oxidation caused by whole-body exposure of mice
Fatemeh
Seif
author
Mohamad Reza
Bayatiani
Ph. D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran.
author
Hadi
Ansarihadipour
Ph. D of Biochemestry. Department of Biochemistry and Genetics, School of Medicine, Arak University of Medical Sciences, Arak, Iran.
author
Ghasem
Habibi
Medicine Student, Hamedan University of Medical Sciences, Hamedan, Iran.
author
text
article
2018
eng
Introduction: Exposure to ionizing radiation can be through direct hit or water radiolysis lead to oxidation in biological systems. In this study, the protective effect of Myrtus Communis aqueous extract on structural changes and oxidative stress in red blood cells and plasma proteins was examined after receipt of ionizing radiation.
Materials and Methods: wistar rats were administered Myrtus Communis aqueous extract (0.5 mg/kg of body weight) for a week before exposing them to a single dose of 6 Gy of 6MV x-ray. Blood samples were collected one hour after irradiation. Changes in the structure of hemoglobin, FRAP and carbonyl assay tests were performed for three groups 1) control, 2) exposed, 3) exposed
+extract
Results: Decrease in the level of oxyhemoglobin (The averages were ±35.36 2.35, 1.35±17.05, and ±26.92 0.45 respectively for control, exposed and exposed +extract was observed (p<0.001). a significant increase in the methemoglobin (0.11±0.47 ,0.585±9.850 and
±5.070 0.139) and hemichrome (0.09±0.77,0.59±6.18 and 1.910.28±) levels were showed (p<0.001). FRAP test and carbonyl assay showed the rate of oxidation in the blood of irradiated rats. The deference between these components was significant (p<0.05).
Conclusion: Pretreatment with aqueous extract of Myrtus Communis can provide the radiation protection against x-ray-induced oxidative damage. The protection may be attributed to the free radical scavenging activity of this extract.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
70
70
https://ijmp.mums.ac.ir/article_12090_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12090
Measuring the Skyshine from Linear accelerator in Rajaee Oncology Hospital
Soodeh
Satayi Mokhtari
Msc Student of Medical Physics Radiobiology and Radiation Protection Department, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Ali
shabestani Monfared
Professor of Medical Physics, Department of Medical Physics Radiobiology and Radiation Protection, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Kourosh
Arbabi
PHD of Medical Physics, SSDL, Iranian Atomic Energy Agency, Karaj, Iran
author
Shahvar
A
PHD of Medical Physics, SSDL, Iranian Atomic Energy Agency, Karaj, Iran
author
Fatemeh
Niksirat
MSc of Medical Physics Radiobiology and Radiation Protection Department, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Kourosh
Ebrahimnejad Gorji
PHD of Medical Physics, Department of Medical Physics Radiobiology and Radiation Protection, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Werya
Parwaie
PHD Student of Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Radiation therapy is using the ionizing radiation to eliminate or minimize cancerous tissues. This method has been very much considered in recent years. Because of the high energy of the photons produced by the accelerator, it is necessary to protect the walls, roof and the floor of the treatment rooms using the concrete and leaden materials. One of these harmful radiations produced in radiation therapy centers is the Skyshine that should be considered in designing the shieldings. Skyshine rays are the primary beams that pass through the ceiling in the vertical direction and scatter in the upper atmosphere above the building and return to the ground; so they transfer radiation dose to a general area outside the radiotherapy room. This study aimed to evaluate and determine the levels of doses resulted from skyshine radiation in Shahid Rajaee Radiation Center of Babolsar in Northern Province of Iran and compare it with the values of international standards.
Materials and Methods: In this survey dose measurement has been done with LS01 ion chamber (1000 cc) and Unidose E electrometer produced by PTW company in 6mv Elekta compact accelerator (made in Germany) with exposing 400MUs and field size of 40*40. The distances of dose measurement were 300, 150, 100, 50 and 25 cm from the external wall of the treatment room and 2.10cm height from the ground. Temperature, pressure and correction factors of electrometer and dosimeter has been considered in results and total dose of skyshine rays based on reformed reading of electrometer acquired for 50 weeks,6 days and 8 working hours.
Results: The dose rate at 25, 50, 100, 150 and 300 cm distances from the external wall of the treatment room were 1.017, 0.79, 0.595, 0.436, 0.275 µsv/h respectively. Also, the standard
deviations were 0.012, 0.007, 0.015, 0.020, and 0.032.
Conclusion: The obtained results were compared with other studies and the annual average worldwide rate; the result was compatible with most studies and was less than the average worldwide= 2.4 mSv/y.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
71
71
https://ijmp.mums.ac.ir/article_12349_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12349
Image quality assessment in digital radiography systems- A Pehamed FLUORAD A+D phantom study
Ali
Chaparian
Associate Professor of Medical Physics, Technology of Radiology Department, Isfahan University of Medical Sciences, Isfahan, Iran
author
Hanie
Kaheni
MSc of Medical Physics, Medical Physics Department, Shahid Sadoughi University of Medical Science, Yazd, Iran
author
text
article
2018
eng
Introduction: The use of digital radiography systems has become more common all around the world. Ideal situation in radiography is to maximize the image quality while minimizing the patient dose. The purpose of this study was to compare image quality and radiation dose in different digital radiography systems.
Materials and Methods: Images of Pehamed FLUORAD A+D phantom in five different tube voltage (50, 60, 70, 75, 80kVp) and five tube current of (100, 250, 360, 400, 560mA) in four different digital radiography systems were obtained. Three images were acquired in each imaging parameters. Image quality parameters (contrast resolution (CR), spatial resolution(SR) and contrast noise ratio(CNR)) were measured for each image. The number of low contrast object as a scale of CR and the number of resolution lead bar pattern as SR were considered. CNR of each image was determined with imageJ software. Dose area product (DAP) which was displayed during acquisition of each image: was recorded.
Results: Image quality parameters (CR, SR, and CNR) as well as DAP were significantly different between different digital systems. It was shown that all four quantities increased with increasing exposure parameters in all systems. At fixed CR of 4 and CNR of 25, DAP value obtained in SEDECAL system was lower than others (p≤0.05)(Fig. 9) and at fixed SR of 3.36(lp/mm), DAP values in SEDECAL and Applem- R302/A were lower than two other systems (p≤0.05).
Conclusion: The results of this investigation can be taken into consideration in the selection and purchasing of new systems in order to preserve patients as well as radiographers from unnecessary dose consistent with the radiation protection principle ALARA.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
72
72
https://ijmp.mums.ac.ir/article_12350_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12350
The modeling of induced current density in eyes from static magnetic fields produce by MR scanner
Mina
Nouri
MSc in Medical Physics Medical Physics and Medical Engineering Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
author
Ali
Zamani
Assistant Professor, Medical Physics and Medical Engineering Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
author
Mehdi
Hoseini
PHD Candidate, Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
Introduction: Staff and patient Movement in static magnetic field MRI scanner induces current density in the human tissues, so cause biologic effects in people. The aim of this study was the Modelling of current density induced by moving individual with different velocities in static magnetic field of magnetic resonance imaging.
Materials and Methods: current density was calculated in a virtual adult male phantom that moved in around of 1/5 T magnetic resonance imaging scanner. (Tissue conductivity properties assume in 1KHz). The current density is computationally determined using the MATLAB software in first By obtaining the electric field induction in the spherical coordinates in the MATLAB software and defining the steps for the phantom, then Maxwell's equations were used to obtain current density so the final formula of the induced current density was obtained, then its value was calculated in different paths and 1 and 2 (m/s) the velocity of the motion.
Results: The average current density induced in the eye tissues at 2 different speeds 1and 2 (m/s) Was obtained Respectively 25/49 and 50/99 (mA/m2).
Conclusion: The electrical characteristics of the eyes are caused induced higher current density than other tissues. This relatively high current density is a good reason for magnetophosphence effect while moving around the magnetic resonance imaging device. The amount of current density induced in the eye tissues increases with increasing speed, so it is advisable to slowly moving for employees and patients in the magnetic resonance imaging room.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
73
73
https://ijmp.mums.ac.ir/article_12351_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12351
A study on the prevalence of hearing loss after head and neckradiotherapy with three-dimensionalconformal radiotherapy (3D-CRT)
Sohaila
Yazdani
MSc of Medical Physics, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Karim
Khoshgard
Assistant Professor, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Mehran
Yarahmdi
Assistant Professor, Department of Medical physics, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Negin
Farshchian
Assistant Professor, Imam Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction:Radiotherapy (RT) plays an important role in treatment of head and neck cancers. In almost 75% of patients with head and neck cancers, RT as the main treatment method is used in order to radical or palliative treatment. Hearing loss is one of the side effects of RT for patients whose inner ear is included in radiation field. The aim of this study was to evaluate the prevalence of hearing loss in patients with head and neck cancers who had undergone three-dimensional conformal radiotherapy (3D-CRT).
Materials and Methods:In this study 68 ears with an average age of 40.2 years (range 16-60 years) were studied. Pure tone audiometry was performed at frequencies of 250, 500, 1000, 2000, 4000 and 8000 Hz. Patients with an acceptable result of audiometry initial test were included in this study. They were evaluated three times: before RT, at the end of RT, and three months after RT. The patient s’ treatment planning was performed using Isogray software and statistical analysis of the results was done with SPSS software.
Results:The results are based on the CTCAE V. 4.03 criteria showed 19% ears at the end of radiotherapy, compared with before treatment were suffering from hearing loss. Three months after the end of radiotherapy, the prevalence and severity of hearing loss increased in patients, so that 37% of the ears having hearing loss. Results Statistical analysis showed that at all frequencies studied, the threshold of hearing at the end and three months after the end of radiotherapy compared to baseline, significantly changed (p≤0.001).
Conclusion:Considering the high prevalence of hearing loss, 37% just three months after the end of radiotherapy, and progressive with time of this complication (an increase of 18% in 3 months), post-treatment auditory care is very important for these patients.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
74
74
https://ijmp.mums.ac.ir/article_12352_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12352
Calculating Reaction Rate of Positron Emitters During Proton Therapy Which Are Used In Online PET Scan by Monte Carlo Method
Kosar
safari
MSc student of nuclear physics, Facultry of science, University of Guilan, Rasht, Iran
author
text
article
2018
eng
Introduction: Nowadays, cancer is one of the most important concerns in human being's societies, more than one-third of people in around the world will get cancer during their lives. Physical dose depth distribution characteristic of protons in a tissue is determined with a low dose in the entrance region, maximum dose in the Bragg region, and rapid decline takes place near the end of their range. The ability to treat internal tumors, the ability of the broadening of the Bragg peak, and the small size of the particles are the other advantages of this approach which cause less damage to healthy tissues surrounding the tumor as compared to other therapy approaches such as radiation therapy with X-ray. At present, fast algorithm is generally used to obtain treatment plan (dose distribution in the patient).
Materials and Methods: At present, fast algorithm is generally used to obtain treatment plan (dose distribution in the patient). This means that at first absorbed dose in water phantom is calculated and then the necessary changes on the beam, equipment and location of the patient are applied, but this approach does not consider the dose resulting from radioactive decay in the tissue. Although radioactive products such as 3H(T1/2=12/32 a), 7Be(T1/2=53/3 d), 14C(T1/2=5730 a), and 22Na(T1/2=2/6 a) which are produced by interaction between protons and tissues' constituent elements have high longevity, they are produced in small quantities, but nuclei that decay to the ground state with positron emission and have low longevity time such as11 C(T1/2=20.3 min), 13N(T1/2=9.96 min), and 15O(T1/2=2.03 min) are produced in amount that calculation of their dose is an integral part of plan treatment. In this study, absorbed dose of protons and secondary particles such as neutrons and positrons in a head phantom have been calculated using the MCNPX 2.6 simulation code. The rate of the production of positron-emitter elements in different interactions have been studied.
Results: Result shows these short-longevity radioactive products reach their maximum amount along the proton path and particularly in Bragg region. In addition, a portion of produced photons from the annihilation of positronium atoms are absorbed by tissues and may cause unwanted dose to be applied to the surrounding treated tissues. Although, their produced dose is low, but they are not negligible and their amount should be calculated on the treatment plan. And amoung them 11C has maximum reaction rate and its production distribution has good agreement to proton dose distribution.
Conclusion: this particles not only are important because of their extera dose but also they are important because of they can be used during online PET scan just after proton therapy to monitor the progress of treatment
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
75
75
https://ijmp.mums.ac.ir/article_12353_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12353
Investigation of acoustic properties of silica coated gold nanoparticle as contrast agent for Ultrasonography
Narges
Kheirollahi
MSc, Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences (SUMS), Shiraz, Iran.
author
Ali
Shakeri-Zadeh
Assistant Prof. of Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran.
author
Maryam
Rezaie Yazdi
MSc, Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences (SUMS), Shiraz, Iran.
author
Alireza
Mehdizade
Assistant Prof. of Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences (SUMS), Shiraz, Iran.
author
Parisa
Pishdad
Assistant Prof. of Radiology Department, Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
author
text
article
2018
eng
Interoduction: Ultrasound images have often low contrast due to small differences in acoustic impedance between different tissues. Air or gas microbubbles that surrounded by membrane are most of the contrast agents in ultrasound imaging. Problems such as instability in sound pressure and inability in penetrating from the blood vessel into body tissues limited the use of microbubbles into the intravascular space. Due to the potential benefits of nanomaterials, extensive research about developing nanoparticle-based contrast agents is done recently. In this work, we investigated acoustic properties of gold nanoparticles coated with silica (Au@SiO2) to use it as an ultrasound contrast agent.
Materials and Methods: In this study, the size of Au@SiO2 nanoparticles was measured by DLS and TEM. Agarose gel samples containing different concentrations of nanoparticles were made. Samples were placed in the Plexiglas container involved deionized water and B mode ultrasound imaging of samples obtained at three different frequencies (6, 8 and 10 MHz). Images were analyzed by MATLAB program. Average of gray Scales and backscatter amplitude were obtained for each image. Effect of increasing concentration of nanoparticles on average of gray Scales and backscatter at three frequencies was measured. Then stability of nanoparticles were examined during insonication.
Results: size and morphology of Au@SiO2 nanoparticles was, 18.67 nm by TEM and 25.8 nm, by DLS. Image brightness levels increased in the samples containing nanoparticles compared to the net agarose gel. brightness level increased with particles number concentration. In three frequencies that we used, in constant concentration with increasing frequency, image gray levels will be increased. Quantitative results of the regression analysis for assessment of backscatter indicated that there is linear relationship between increasing backscatter signal and particles concentration at 8 and 10 MHz, but at 6 MHz didn’t observed association between this two values. Also didn’t observed significant change in particle size distribution after 30 minutes exposure by ultrasound.
Conclusion: Our results show that appropriate concentration of Au@SiO2 nanoparticles have ability to improve effective contrast. Proper particle size distribution caused these particles to penetrate from pores of vessels of tumor tissue and accumulate in cancer cells. more stability of these particles against ultrasound waves compared to Microbubbles caused their to be usefulness for long-term ultrasound imaging and guide and monitor treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
76
76
https://ijmp.mums.ac.ir/article_12354_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12354
Dose Reduction Methods in Chest Computed Tomography
Vida
sargazi
M.S of medical physic., Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Email: vida.sargazi8@gmail.com
author
zeynab
yazdi sotode
M.S of mri., Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Email:zeynab-yazdi2016@yahoo.com
author
jalal
ordoni
M.S of radiobiology., Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Email
author
text
article
2018
eng
Introduction: Computed tomography is one of the most powerful tools for investigating thorax disease, because it shows progression of lung disease much clearer than chest radiography. Technical advances in CT scanners have led to some abilities for CT scanners such as coverage of larger volume, lower noise and ability for acquiring image in one respiratory phase. However, this will be accompanied by more radiation exposure to patient and research shows that CT gives higher exposure dose to patient in comparison with conventional radiography.1
Materials and Methods: In each computed tomography (CT), patient dose is dependent on the scan parameters. Scan parameters are included kV, mA, scan field of view (SFOV), rotation time, focal spot size, slice width and pitch. Also, shielding of sensitive organs such as breast which is not interest organ during chest CT scanning is one of the dose reduction methods. Furthermore, Type of scanner, methods and protocols of scanning, for example in multi-slice scanners there is some more cases like collimation, which effect on patient dose, and therefore all of these options should be adjusted, accurately. It is considerable that scan parameters such as reconstructed matrix and reconstruction algorithms have considered in this paper; however, these parameters do not impact directly on patient dose but they have some affects through changing the characteristics of the image indirectly.
In this study twenty methods for radiation dose reduction in thorax CT were explained.
Conclusion: According to the principle of ALARA, the aim of applying optimization techniques is to reduce the amount of receiving dose while maintaining image quality.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
77
77
https://ijmp.mums.ac.ir/article_12355_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12355
Measure and calculation the specific absorption rate due to 900MHz waves in the brain, skin, fat and bone tissues
Fatemeh
Seif
Ph. D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran.
author
Mohamad Reza
Bayatiani
Ph. D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran.
author
Nayer sadat
Mostafavi
Msc of Medical Physics, Khansari hospital, Arak, Iran.
author
Mahsa
Shakeri
Msc of Radiobiology, Tehran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Communication between mobile phones and antenna BTS (Base Transceiver station) is carried by electromagnetic waves. Energy associated with these waves can be absorbed by biological tissues. so Widespread use of these devices has generated public concern about exposure to electromagnetic waves. In this study the electric field intensity and specific absorption rate in the radiology, emergency, general hospitalized and diagnostic laboratory departments was obtained in Arak, IRAN
Materials and Methods: In this study, using radiometer (TES 592), the electric field measurements were performed in two modes of average (Average = Avg.) And Maximum Average (Max. Avg.) For six minutes in accordance with the recommendations of the ICNIRP and IEEE Committees in the 900 MHz frequency. then using the equation Specific Absorption Rate induced in brain, skin, fat and bone tissues were calculated and compared with the thresholds recommended by the International Commissions
Results: The results showed that the mean value of the electric field was 1.334 V/m which is almost 2.7% threshold introduced by International Commission on Non-Ionizing Radiation Protection (ICNIRP) and 2.6% threshold adopted by the Institute of Electrical and Electronics Engineers (IEEE). The highest SAR value was calculated 1.6W / Kg for skin that is lower than the threshold values of ICNIRP(2W/Kg) and IEEE(1.6W/Kg)
Conclusion:The results of the present study showed that for both quantities in Arak hospitals the values greater than the threshold announced by committees such as IEEE and ICNIRP are not observed. To deal with the concerns of the community that is generally caused by a lack of awareness the educational and public awareness programs should be developed
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
78
78
https://ijmp.mums.ac.ir/article_12356_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12356
Investigation the potential of Boron neutron capture therapy (BNCT) to treat the lung cancer
Mansour
Zabihzadeh
Associate Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mohammad Ali
Behrooz
Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Amir
Danyaei
Assistant Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Hojattolah
Shabazian
Associate Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Farnaz
Rahimli
MSc Student, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction: Boron neutron capture therapy (BNCT) is recommended to treat the glioblastoma tumor. It is well known that neuron beams are more effective treatment than photon beams to treat hypoxia tumors due to interaction of neutron with nucleus and production of heavy particles such as 7Li and alpha particle. In this study to evaluate the suitability of BNCT for treating of lung cancer, the dose distributions of neutron beam were calculated in lung tumor volume and in peripheral organs at risk (OARs).
Materials and Methods: Dose distribution in Boron neutron capture therapy to treat lung cancer was calculated by MCNPX (2.6.0) code. A 3×3×3 cm3 tumor was located in left lung of ORNL phantom and was irradiated with a rectangular field of neutron positioned at surface source distance (SSD) of 10 cm. recommended spectrum of MIT (Massachusetts Institute of Technology) was used. Tumor was loaded with different concentrations of Boron 0, 10, 30 and 60 ppm. Dose delivered to OARs such as heart, spinal cord, right lung … were calculated.
Results: The results show that neutron flux significantly decreased followed to penetrate in lung tissue. Neutron flux decreased in all energy bins of irradiated MIT spectrum; maximum fall- off occurred in the range of epithermal energy. Dose distribution was not depended to SSD. The absorbed dose in tumor was 2.16×10-14, 2.6×10-14, 3.44×10-14 and 4.72×10-14 Gy(per one irradiated neutron from source) for boron concentration of 0, 10, 30 and 60 ppm, respectively. From the OARs, the heart tissue absorbed the maximum dose of 1.66×10-15 Gy (per one irradiated neutron from source).
Conclusion: Our simulated model was successful to calculated organ doses in BNCT. As the boron concentration in lung tumor increases, absorbed dose increased while dose uniformity trended downward. Our results show that the MIT neutron source is suitable to treat deep lung tumors while OVRs’ dose maintains within the threshold dose.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
79
79
https://ijmp.mums.ac.ir/article_12357_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12357
New Physical Approaches combined with nanoparticles in Leishmania major Treatment
Elham
Dolat
Medical physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Khadije
Mayelifar
Medical physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Sajedeh
Yadegari-Dehkordi
Medical physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Ahmad Reza
Taheri
Medical physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Ameneh
Sazgarnia
Medical physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
author
text
article
2018
eng
Introduction: Cutaneous leishmaniasis is a mutual parasitic disease, which is endemic in some countries of the world. The use of common drugs has been restricted because of confirmed side effects and drug resistance. There are still serious challenges in the treatment of CL. Developing new therapeutic methods for leishmaniasis, besides obtaining a prompt treatment response that prevents lesions' progression and scarring, is a significant success in the treatment of the disease. Novel approaches such as nanotechnology have been applied as a therapeutic modality. This study aimed at evaluating the influence of three physical approaches combined with nanoparticles on promastigotes, amastigotes, and lesion-induced parasites.
Materials and Methods: Leishmania promastigotes were treated with gold nanoparticles combined with different duration of the microwave with 2450 MHz frequency. So, the promastigotes treated with electroporation and ultraviolet irradiation in presence of silver and titanium dioxide nanoparticles respectively. Leishmania amastigotes were preserved by GNP and SNP with different conditions exposure of Microwave irradiation and electroporation. Ultraviolet irradiation in presence of silver nanoparticles used to reduce the size of lesion-induced parasites.
Results: Promastigotes survival rate induced a significant decline in different conditions of all three approaches in the presence of nanoparticles in comparison to similar samples without there. The least survival of amastigotes was also recorded in the groups containing nanoparticles received the microwave and electroporation. In addition, the findings on parasite burden and size of lesions showed a significant difference between the treatment groups with SNPs and UV irradiation and control group.
Conclusion: The finding emphasized to the utility of new approaches by nanotechnology could be useful for the treatment of cutaneous disease such as leishmaniasis. For validation of this statement need to more research and some studies have been planned for this aim.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
80
80
https://ijmp.mums.ac.ir/article_12358_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12358
Comparison of Dosimeters Between Radionuclides in Brachytherapy for Liver Cancer
Arezou
karimian
Department of medical radiation Science and Research, Islamic Azad University, Tehran Iran
author
Asghar
Haddadi
Department of medical radiation Science and Research, Islamic Azad University, Tehran Iran
author
text
article
2018
eng
Introduction: One of the methods for treating metastatic primary liver cancer is brachytherapy, using 90Y
−
with a half-life of 64.1 hours and an energy of 2.28MeV and decay 𝛽 is a good treatment
for treating HCC Liver cancer. But brachytherapy using 90Y because the dose distribution and dose concentration in the tumor and organs surrounding the tumor can not be seen in treatment and Images are taken with radionuclide using SPECT or annihilation radiation using PET and Chernokov radiation, have problems such as low resolution and imaging difficulty. Therefore, to solve this problem, use radionuclides such as 153Sm with a half-life of 46.3 hours and 177Lu with a half life of 6.71 days and 166Ho with a half-life of 26.8 hours
.
Materials and Methods: here ecause of the high precision of voxel phantoms ICRP110 is used for dosimetry calculations. And these phantoms include the whole female body phantom with height and weight of 163cm and 60kg, which consists of more than 14 million voxels, and the female phantom voxel is 1.775mm * 1.775mm * 4.8mm. In this phantom, the bone tissue is comprised of compressed bone and the red and yellow bone marrow and the weight percentages of blood are also calculated for any soft tissue, and due to the accuracy and resolution of this phantom, it is suitable for simulating and calculating the internal dosimeter. Using the fluka code in Monte Carlo, given the precise and resolution of this phantom, it can simulate the human body to calculate the internal dosimetry. Calculated with radionuclides 90Y, 153Sm, 177 Lu, 166Ho, and the amount of doses in the liver and around the liver (kidneys, lungs, heart, stomach, pancreas, vesicles, and bone marrow).
Results: By comparing organs between Liver, lung right, lung left, Heart contents, ribs cortical, ribs spongiosa, Heart wall, Gallbladder contents, kidney cortex right, stomach contents, pancreas stomach wall, spleen, kidney cortex left, Gallblladder wall kidney medulla right, , ,kidney medulla left,kidney pelvis right, kidney pelvis left , The highest dose is for the liver and the right lung And the lowest for kidney pelvis right kidney pelvis left. Conclusion: Here we compare radionuclide to find best for treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
81
81
https://ijmp.mums.ac.ir/article_12359_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12359
A study on the accuracy of motion tracking of thoracic tumors at radiotherapy with external surrogates
Seyyed Amirreza
Dastyar
Medical Radiation Division, Faculty of New Sciences and Technologies, Graduate University of Advanced Technology, Haftbagh St. Kerman, Iran, 7631818356
author
Ahmad
Esmaili Torshabi
Medical Radiation Division, Faculty of New Sciences and Technologies, Graduate University of Advanced Technology, Haftbagh St. Kerman, Iran, 7631818356
author
text
article
2018
eng
Introduction: In radiotherapy with external surrogates, exact information of tumor position is one of the key factors that improves treatment delivery. Many dynamic tumors in thorax region of patient move mainly due to respiration and are known as intra-fractional motion error that must be compensated, as well. One of clinical strategy is using Stereotactic Body Radiation Therapy with external surrogates has been proposed to compensate motion error. In this strategy, prediction model is one of main component as responsible to track tumor motion in real time. In this study, a prediction model based on the fuzzy logic concept is proposed for real time tumor tracking during tumor treatment. Several approaches have been proposed for this aim using linear and non-linear prediction models, but a fuzzy environment may be optimal due to its robustness and benefits.
Materials and Methods: The fuzzy model is configured using training dataset provided by monitoring systems with detecting tumor motion and external rib cage motion of ten patients treated with Cyberknife Synchrony System at Georgetown University Hospital. After configuring, the model is ready to trace tumor motion during therapeutic beam irradiation. In our study, we investigated the effect of the number of data clusters, fuzzy inference system type on the performance accuracy of our model. In order to assess the performance of our model, the predicted tumor motion was compared with respect to the state of the art model.
Results: In this work we utilized Root Mean Square Error (RMSE) as common available mathematical metric for illustrating the performance uncertainty error of fuzzy prediction model. As resulted, the mean value of RMSE over ten patients is 5.45 mm Moreover, by implementing sugeno method the RMSE is remarkably less than the same calculation by means of Mamdani method. Moreover, the computational time will be significantly decreased using Sugeno type. As example, the run time improvement is almost 33% for one typical patient with left lob lung cancer.
Conclusion:A fuzzy logic based prediction model was assessed in this work to predict tumor motion as real time during external radiotherapy. The benefits of implemented fuzzy inference system in model learning and its simplicity during running has made it feasible, robust and very promising for real clinical application.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
82
82
https://ijmp.mums.ac.ir/article_12360_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12360
Dual frequency ultrasound-enhanced tissue plasminogen activator thrombolysis in an in vitro human clot model
Mosayyeb
Mobasheri
Department of Medical physics, Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Manijhe
Mokhtari-Dizaji
Department of Medical physics, Faculty member of Medical Sciences, Tarbiat Modares University, P O Box: 14115-331, Tehran, Islamic Republic of Iran Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
author
Tayebeh
Toliyat
Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
author
Masoud
Mehrpour
Department of Neurology, Firoozgar Hospital, Firoozgar Clinical Research Development Center (FCRDC), Iran University of Medical Sciences (IUMS), Tehran, Iran
author
text
article
2018
eng
Introduction: Stroke causes death and disability in patients throughout the world. At present, the only FDA- approved drug for ischemic stroke is recombinant tissue plasminogen activator (rt- PA). Unfortunately, rtPA can cause intracerebral hemorrhage and must use within limited time window (within 3-4.5 hour after onset of stroke). Ultrasound with rtPA loaded liposomes (rtPA_L) was suggested as adjuvant therapy that reduce the dose of rt-PA and increase its efficiency. Different frequency protocols such as kHz and MHz were used for sonothrombolysis. In this study, we suggested a protocol including both kHz and MHz with rtPA_L The kHz wave could fragment rtPA_Ls and release rtPA, the MHz enhances lytic efficiency of released rt-PA by stable cavitation and its microstreaming. This protocol may reduce bioeffect of ultrasound wave and simultaneously at least maintain rt-PA lytic effect.
Materials and Methods: The rt-PA loaded liposomes were prepared by hydrating lipid film with rt-PA and freezing liposomes under air pressure (4 atm). Cylindrical human whole blood clots (1 mm diameter) formed in and around micropipette at 37 ˚C. In combination with rtPA_L ([rtPA]=50 μg/ml) and human plasma, three protocol were used: 1 MHz (1.5 W/cm2_ 30 minutes), 130 kHz (
0.01 W/cm2_10 s) + 1 MHz (0.5 W/cm2_ 30 minutes) and control. Clots were imaged under microscope and clot lysis were quantified by measuring clot diameters before and after sonication.
Results: Statistical analysis of clot diameter varation between two sonication groups (1 MHz (1.5 W/cm2_ 30 minutes), 130 kHz ( 0.01 W/cm2_10 s) + 1 MHz (0.5 W/cm2_ 30 minutes)) do not show significant difference.
Conclusion: Not significant difference between two sonication groups indicates that the dual frequency protocol by using less energy and consequently lower bioeffects may have similar effect as single frequency protocol.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
83
83
https://ijmp.mums.ac.ir/article_12361_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12361
Quantitative evaluation of TOF benefits indifferent tumor regions of Overweight patients in clinical PET/CT scanner
Hanieh Sadat
Jozi
Department of Medical Radiation Engineering, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran. (hanieh_jozi69@yahoo.com)
author
Pardis
Ghafarian
Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran. (pardis.ghafarian@sbmu.ac.ir)
PET/CT and Cyclotron Center, NRITLD, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Using TOF information in image reconstruction reduce the noise propagation along the LOR during forward and back projection of the data, and improve the image signal-to-noise ratio (SNR) of PET scanners. This improvement is dependent on the scintillator decay time, time response of coincidence circuits and front-end electronics. The goals of this study were to evaluate the benefits of time of flight (TOF) in clinical PET/CT images of overweight patients in relation to the tumor-to-background ratios, and to determine what SNR gains in PET performance could be achieved.
Materials and Methods: 32 overweight patient studies with normal 18F-fluoro-deoxyglucose (18F-FDG) uptake were chosen. FDG-PET/CT imaging was performed on the LYSO-based PET component of Discovery RX PET/CT scanner. Various tumor sizes in different locations of the thorax and abdomen in PET images have been investigated. The PET data were reconstructed with the baseline ordered-subsets expectation maximization (OSEM) algorithm+ PSF model and OSEM + PSF + TOF model. The image quality was evaluated using AMIDE to estimate the SNR, contrast, coefficient of variation(COV), and the standardized uptake values (𝑆𝑈𝑉𝑚𝑎𝑥). The results were then subjectively analyzed as a function of patient body-mass index (25<BMI < 30 and BMI ≥ 30), and type of imaging (TOF and Non-TOF).
Results: The results demonstrated reduction in COV when utilizing TOF algorithms. The reduced COV using TOF reconstruction was 30% among patients with 25 <BMI <30. The maximum SNRgain and CNR, for a tumor with an average size of 2 cm for overweight patients (BMI ≥ 30) in the lung region were obtained 54% and 33%, respectively. Also, the maximum SUV value for larger patients is enhanced by 24% and 14% in the lung and abdomen, respectively.
Conclusion: The results confirmed advantages of TOF information in image reconstruction including better identification of image details, better contrast, and image noise reduction in terms of SNR. Thus, the clinical studies demonstrate the improved contrast of the smallest tumor for larger patients (BMI ≥ 30) with TOF. These gains are evident from visual inspection of the images as well as a quantitative evaluation of contrast recovery of the smallest tumors and noise in different background.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
84
84
https://ijmp.mums.ac.ir/article_12362_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12362
Study of the therapeutic effect of fullerene nanoemulsion on wrinkle repair of C57BL6 mouse animal model with high frequency imaging
Mohadese
Estaji
Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Manijhe
Mokhtari-Dizaji
Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Mansoureh
Movahedin
Department of Anatomy, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Arash
Padash
Department of Medical Nanotechnology, Faculty of Advanced Sciences & Technology, Pharmaceutical Sciencees Branch, Islamic Azad University, Tehran, Iran
author
Sahar
Ghaffari Khaligh
Department of Pathology, Faculty of Veterinary Medicine, Semnan University, Semnan, Iran
author
text
article
2018
eng
Introduction: One of the most obvious morphological changes due to aging is the formation of facial wrinkles, which are remarkably visible at middle ages and can have a significant effect on the quality of life of individuals. It is believed that UVB is one of the main causes of aging by stimulating reactive oxygen species. Nanoemulsion was loaded with fullerene, a strong free radical scavenger, and its efficacy to provide protection and regenerative effect against ROS-induced collagen breakdown in C57BL6 mouse animal model of skin was studied by recording high-frequency ultrasound images and evaluating the depth of heath layer of the tissue including the dermal and epidermal layer.
Materials and Methods: Nanoemulsions formation was carried out using a method based on high energy emulsification technique. Oil phase (Fullerene (C60), white beeswax, Span 80 Phenonip, Palmkerneloilesters) and aqueous phase (xanthan gum, Tween 80, Water deionized) were separately preheated up to 75 ± 1 C. Fullerene nanoemulsion was prepared by adding the aqueous phase dropwise into the oil phase and homogenizing the mixture at 3000 rpm using a high shear homogenizer at room temperature (25 ± 2 C) for 20 min. The premixed emulsions were further subjected to ultrasonication by 24 kHz ultrasonic tip processor with a maximum power output of 400 W. The C57BL6 mouse animal model was exposed to radiation induced aging for5 weeks (5 times a week) with radiation intensity of 0/03 mW/ cm2 and then devided into two groups: control(5mice) and treatment(5mice) Subjects were instructed to apply 0.5 mL of fullerene nanoemulsion at a concentration of 1000µg/ml for28 days (twice a day in the morning and at nigh) in the form of topical UV radiation. Physical parameters were measured weekly (up to 4weeks) during the treatment wrinkles from ultrasound images with a resolution of 0/001mm and in the groups analyzed as mean and standard deviation.
Results: The percentage of changes in the thickness of the epidermis layer on the seventh day in the control group increased by 2%, in the treatment group with a fullerene nanoemulsion decreased by13%, on the 14th day in the control group increased by 5%, and in the treatment group decreased by 32%, on the 21th day in the control group and treatment decreased by 0% and 37% and on the 28th day in the control group and treatment groups, respectively increased by 2% and decreased by 43%. The percentage of changes in the thickness of the dermis layer on the seventh day in the control group increased by 1%, in the treatment group with a fullerene nanoemulsion decreased by21%, on the 14th day in the control group increased by 4%, and in the treatment group decreased by 28%, on the 21th day in the control group and treatment decreased by 3% and 34% and on the 28th day in the control group and treatment groups, respectively increased by 1% and decreased by 37%.
Conclusion: The physicsl parameters of the skin layers resulting from the processing of ultrasound images (thickness or skin layers) significantly decreased during the treatment process in the animal model of the mouse. Therefore in the present study the effect of the fullerene nanoemulsion regeneration on the basis of the processing of consecutive ultrasound images with high resolution in wrinkle repair is proposed.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
85
85
https://ijmp.mums.ac.ir/article_12363_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12363
Increased Absorption Dose with the Presence of Gold Nano particles in a Normoxic Polymer Gel: Method Monte Carlo
Hossein
Tavakoli-Anbaran
Associate Professor, Faculty of physics and Nuclear Engineering, Shahrood University of Technology, Shahrood, Iran. Tel:
author
Abolfazl
Mahmoodi
Master Student, Faculty of Physics and Nuclear Engineering, Shahrood University of Technology, Shahrood, Iran.
author
text
article
2018
eng
Introduction: Radiotherapy involves all methods that can provide a special amount of ionizing radiation to malignant tissue with the assumption that minimal damage to healthy tissues is achieved. We are looking for a valuable and reliable method to measure the absorption dose and also the ability to measure the absorption dose distribution in three dimensions, which today is the only three-dimensional dosimeter the use of radiation- sensitive polymer gels. The purpose of this study was to calculate the amount of increase in absorbed dose with the presence of nanoparticles the gold is uniformly atomic in the polymer gel, with a high atomic number. According to the rules of photon interaction with matter, the probability Photovoltaic absorption is approximately equal to the third power of atomic matter of the target material, and has a direct relation with the third power of photon energy.
Hence, the use of gold nanoparticles with high atomic numbers along with low-energy photon rays to increase absorption dose.
Materials and Methods: Montecarlo calculations were performed to determine the absorption dose due to iridium -192 source with MCNPX code. From the gel Polymer-type neuro- muscular as a phantom to measure the amount of increased absorbing dose by adding nanoparticles of gold in a polymer gel uniformed with various concentrations under the irradiation -192 radiation rays
Results: By increasing the gold nanoparticles in polymer gels with a concentration of 0.1mM to 1.5mM, the maximum absorption dose from 1% to 11% in energy 1.1Mev increases gamma rays. Also, in 0.65MeV energy, the increase is similar to the previous one.
Conclusion: The results of this study, which was obtained by simulation, show that the optimum concentration of nanoparticles the gold in the polymer gel has a uniformly uniform type of protein to achieve a maximum absorbance dose of 1.5mM with increasing 11% in energies of 0.65MeV and 1.1MeV. The results show that the polymorphic gel of the Normoxic type can be called phantom of the soft tissue of the human body and the addition of gold nanoparticles with high atomic number and the concentration obtained can be the highest dose increase this method can be used to conduct clinical studies.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
86
86
https://ijmp.mums.ac.ir/article_12364_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12364
Thyroid dose and dose reduction method from CT scan of head and neck
Fatemeh
Shahraki
B.S. student of radiology, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan.
author
Vida
Sargazi
M.S of medical physic., Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Email: vida.sargazi8@gmail.com
author
Zohre
Bidari
B.S. student of radiology, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan.
author
Jalal
Ordoni
M.S of radiobiology., Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Email jalalordoni@gmail.com
author
text
article
2018
eng
Introduction: Computed tomography (CT) consists of 11% of all imaging methods, but accounts for approximately 67% of radiation exposure due to diagnostic cases. More than one-third of all CT scans are done in the head and neck area. The thyroid gland is irradiated during CT head and neck. According to studies, this gland has the highest levels of radiation-induced cancer, and in children, due to longer life expectancy than adults, cancer has a greater chance of developing and developing. Therefore, awareness of the amount of thyroid dose and dose reduction methods are essential.
Results: According to the results, when performing CT scans of the head and neck, thyroid gland radiation is very high, but the use of optimization techniques leads to a decrease in the amount of thyroid receiving dose. Dose optimization is divided into three stage s: 1-Before scanning 2- During the scan, which includes: patient position, scan parameters, and shields inside and outside the field; 3- After scanning, which includes: rehabilitation filter and quality control. For example, the use of protective shields during head and neck CT tests leads to a reduction in the thyroid dose of approximately 40% to 60%.
Conclusion: According to the principle of ALARA, the aim of applying optimization techniques is to reduce the amount of thyroid receiving dose while mainta ining image quality. The most effective of these techniques in head and neck CT scans is the use of protective shield that minimizes the thyroid dose
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
87
87
https://ijmp.mums.ac.ir/article_12365_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12365
The Comparison of the shares of stopping power in a soft tissue-equivalent material
Somayeh
Jahanfar
Ph. D student, Faculty of Physics and Nuclear Engineering, Shahrood University of Technology
author
Hossein
Tavakoli-Anbaran
Associate Professor, Faculty of Physics and Nuclear Engineering, Shahrood University of Technology,
author
text
article
2018
eng
Introduction:
Proton therapy is a type of radiation treatment that it uses protons to treat cancer. Because of the protons’ unique ability to distribute the radiation dose more directly to the tumor, it minimizes the damage to nearby healthy tissues. The rate of energy loss by the ion in the target is called stopping power. The total stopping power is sum nuclear and electronic stopping power. Electronic stopping power refers to the slowing down of a projectile ion due to the inelastic collisions between bound electrons in the medium and the ion moving through it. Nuclear stopping power refers to the elastic collisions between the projectile ion and atoms in the target.
Materials and Methods:
It should be noted that soft tissue-equivalent material denotes a substance, with absorbing and scattering properties for a given radiation that sufficiently match those of a certain biological tissue. The soft tissue-equivalent material usually consists of four elements of hydrogen, oxygen, carbon and nitrogen. By using the SRIM code, we calculated the total stopping power in each element for 10-MeV proton beam. Then, using Bragg's rule, we got the total stopping power for these elements. Also, using the same code, we obtained the total stopping power for the compound. Also, we obtained the contribution of nuclear and electronic stopping power to the total stopping power in this material.
Results:
By comparing, we observed that the peak height of stopping power using Bragg's rule is more than 20% higher than the SRIM code. This is due to the core and bond (CAB) corrections at low energies in the SRIM code. Also, we observed that total stopping power is due to the electronic stopping power in high energies. By reducing energy, the electronic stopping power is slowly reduced, and the share of nuclear stopping power slowly increases, and the intersection of these is at 50eV energy. Then the contribution of the nuclear stopping power is greater.
Conclusion:
The proton therapy to treat cancerous tumors is a major technological advance. In low- energies CAB corrections must be taken into account for stopping power of the compound, and therefore, the peak height of the stopping power is reduced. In soft tissue equivalent material for proton beam the contribution of the nuclear stopping power at energies of less than 50 eV is greater than the electronic stopping power. In other energies, the electron- stopping power share is dominant.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
88
88
https://ijmp.mums.ac.ir/article_12416_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12416
Radiothermotherapy for glioblastoma multiforme: A preliminary study
Leila
Khalafi
Department of medical physics school of medicine Iran university of medical sciences, Tehran, Iran
author
Seied Rabie
Mahdavi
Department of medical physics school of medicine Iran university of medical sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Glioblastoma multiforme (GBM) is a highly radioresistant cancer with low survival rate. Current therapy approaches have failed to treat GBM. The aim of this study was to assess how GBM tumors respond to combination of hyperthermia and radiotherapy.
Materials and Methods:
In this study, 38 GBM patients were included. 19 patients were treated with 60 Gy radiations in 30 fractions and 19 patients received 60 Gy radiation and 10-12 hyperthermia seasons. Hyperthermia was done using 13.56 MHz radiofrequency radiation, with capacity electrodes. All hyperthermia regimens were delivered one hour before radiotherapy. For all patients, Karnofsky Performance Status (KPS) and tumor volumes were assessed before and 3 months after treatment.
Results:
Our results showed that KPS was improved in hyperthermia group rather than radiotherapy group. In regard to tumor volume changes, 2 and 3 patients had more than 50% and 20-50% decrease in tumor volume post radiotherapy respectively and 7 patients had no change. Also, 2 and 5 radiotherapy patients had more than 50% and 20-50% increase in tumor volume respectively. In hyperthermia groups 8 and 4 patients had more than 50% and 20-50% decrease in tumor volume respectively and 5 patients had no changes. In addition, 2 patients had 20-50% increase in tumor volume.
Conclusion:
Our results identified that combination of hyperthermia and radiation is a feasible approach to treat GBM patients and patients quality of life.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
89
89
https://ijmp.mums.ac.ir/article_12417_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12417
Effect of the radiation field of view and angle in unconventional angiography on patient doses: a Monte Carlo simulation study using a voxelized phantom
Bijan
Hashemi
Ph.D., Associate Professor, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Parisa
Nafar
M.Sc. Graduate, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Ahmad
Bitarafan-Rajabi
Ph.D., Associate Professor, Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction:
We aimed to investigate the effect of variation of beam angle and field of view (FOV) on organs’ and effective doses for patients undergoing interventional cardiology examinations by using Monte Carlo simulations and ICRP110 phantom.
Materials and Methods:
Simulations were done for energies obtained from experimental measurements on the left ventricle phantom of the Axiom Artis model of an angiography system by Monte Carlo N- Particle System code (MCNP). The ICRP110 voxelized whole body model representing an average patient was employed at posterior anterior (PA) position. To guide the x-ray source, the approximate spherical coordinates were set at: 27, 27.135. The collimated x-rays beam was directed toward the patient's body over 16´16 and 25´25 cm2 field sizes for twenty alternative proposed techniques and their resulting effective doses were estimated and compared with those obtained for six relevant routine techniques of coronary angiography including LAO40-CAUD40, LAO45, LAO60-CRA20, PA-CRA45, RAO20-CAUD20 and RAO30,
used at a hospital.
Results:
Variation of the angle and FOV for the 25´25 cm2 field size resulted in dose reduction for some of the proposed techniques including the LAO20-CAUD20, LAO20-CAUD45, LAO60- CAUD20, LAO60-CAUD45, LAO30, LAO60-CRA30, RAO10-CAUD30, RAO30-CAUD30, RAO20
and RAO40 with an amount of 12, 15, 27, 74, 40, 54, 50, 56, 13 and 38 percent respectively. But, for the 16´16 cm2 field size, the dose reduction was observed just for the LAO60-CRA30, RAO10-CAUD30 and RAO30-CAUD30 proposed techniques with an amount of 41, 16 and 38 percent respectively.
Conclusion:
By appropriate variation of the beam angle and FOV, the number/volume of the critical organs exposed directly to primary x-rays can be reduced and lead to the reduction of effective dose while keeping the target organ within the radiation field.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
90
90
https://ijmp.mums.ac.ir/article_12418_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12418
Quantification the dosimetric parameters of asymmetric physical wedged-6MV photon beam
Mansour
Zabihzadeh
Associate Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Seyed Mohammad
Hoseini
Associate Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Sholeh
Arvandi
Assistant Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mojtaba
Hoseini- Ghahfarokhi
PhD student, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
hamideh
mazraeh
MSc of Medical Physics, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Farnaz
Rahimli
MSc of Medical Physics, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mahbube
Fadaei
MSc of Medical Physics, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction:
Physical wedge as a useful tool has been utilized in radiotherapy to modify photon beam shape and intensity such that it distributes dose uniformly in tumor site and reduces hot points. Since during Linac commissioning dosimetric parameters like output factors and lateral dose profiles are measured only for symmetric open and wedged fields, so calculation the parameters for asymmetric wedged fields become necessary. The study aims to achieve output factors and dose profiles for symmetric and asymmetric wedged fields of 6 MV photon beams.
Materials and Methods:
The Siemens PRIMUS Linac head for 6 MV photon beam was simulated by BEAMnrc and all dose calculations were performed by DOSXYZnrc code. Percentage depth dose (PDD) and profiles for open and wedged (15° and 45°) fields were compared with corresponding measurements. Wedge factors for 10 x 10 cm2 field size as a function of lateral distance from central axis were obtained as well for half beam (negative or positive Y jaws were closed) wedged fields. All mesurments were carried out using 0.125 cm3 Farmer type ionization chamber with DOSE1 electrometer (FC65G, Scanditronix-Wellhofer, Germany) at the depth of 10 cm with source to surface distance (SSD) of 100 cm in 50 cm3 PTW-Blue water phantom and processed by dosimetry software RFAplus (Version 5.2, Scanditronix-Wellhofer, Germany).
Results:
The calculated doses were in agreement with measured data that confirmed the simulated MC model. The output factors on the central axis of symmetric wedged beams decreased to 0.693 and 0.307 for 15˚ and 45˚ wedges, respectively. The total photon fluence of 15˚ and 45˚ physical wedged fields reduced to 71.6% and 27.7% of fluence for open field, respectively. It was found that the output factor for asymmetric wedged fields is lower than ones from symmetric fields, particularly at field edges.
Conclusion:
The presences of physical wedge across the beamline decrease the photon fluence and cases beam hardening both for symmetric and asymmetric wedged fields. Lack of scattering photons near the half beam edges in asymmetric wedged field causes a dose fall off in these regions where have potential to overestimate the calculated dose by treatment planning system and consequent cold spots at target volume. Our calculated correction coefficients are recommended to calculate doses by TPS in case of asymmetric wedged fields.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
91
91
https://ijmp.mums.ac.ir/article_12419_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12419
Hypopituitarism in adult patients with non-pituitary brain cancer following radiation therapy
Jalal
Ordoni
MSC of Radiobiology, Department of Radiology, Faculty Member of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran
author
Dariush
Askari
MSC of Radiobiology, Department of Radiology, Faculty of Paramedicine, Shahid Beheshti University of Medical Science, Tehran, Iran
author
Yazdan
Salimi
MSC of Medical Physic, Department of Biomedical Engineering and Medical Physics, Faculty of medicine, Shahid Beheshti University of Medical Science, Tehran, Iran
author
text
article
2018
eng
Introduction: The purpose and our novelty of the current study were to evaluate the HPA
function in adult survivors of primary non-pituitary brain tumors and its association with treatment-related factors such as received dose to the organs at risk, age at irradiation, surgery, and adjuvant chemotherapy in patients treated with RT for brain tumors. Moreover, it aimed to achieve the threshold incidence of late effects because of irradiation to HPA, improve the management of these patients, and improve their quality of life after treatment.
Methods and Materials: Thirty-one (31) patients treated with primary or postoperative radiotherapy (RT) for various cancers in the brain region without pre-existing hypothalamic pituitary (HP) disorder from other causes were prospectively evaluated. Serum samples were obtained from the patients to determine levels of growth hormone (GH), thyroid- stimulating hormone (TSH), and free thyroxine (FT4). Serum samples were measured before treatment, 3 and 6 months after completion of radiation therapy (RT). The hypothalamus- pituitary axis (HPA) and dose volume histograms (DVH) of the patients were derived from their computed tomography-based treatment plans.
Results: Clinical hypopituitarism was not observed, but 83% of patients who tested for hypopituitarism demonstrated subclinical hypopituitarism after a median interval of 6 months. Subclinical GH and TSH deficiency were observed in 17 (54%) and 9 (29%) participants, respectively. Significant declines in TSH (p < 0.021), FT4 (p < 0.009), and T4 (p
< 0.036) levels after the RT course that can be interpreted as subclinical central hypothyroidism were observed. Adjuvant chemotherapy and surgery did not significantly influence the hypopituitarism (p = 0.698, p = 0.287, respectively). The doses of radiation to the HPA region ranged from 241 to 5941 cGy (2.4-59.4 Gy). The mean received dose (Dmean) and biological effective dose (BED) to the pituitary were 36 and 59.6 Gy, respectively.
Conclusions: Subclinical findings of late radiation effects were observed in the HPA. Radiation-induced hypopituitarism and central hypothyroidism are regarded as primary damage to the pituitary gland. The damage is dependent on follow-up. Neuronal cell death and degeneration because of the direct effects of radiation seem to play basic roles
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
92
92
https://ijmp.mums.ac.ir/article_12420_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12420
Combined Effects of 528 Hz Sound and X-ray in Peripheral Blood Lymphocytes
Afshin
Nejadjahantigh
Student Research Committee, Babol University of Medical Sciences, Babol, Iran
author
Kourosh
Ebrahimnejad Gorji
Department of Medical Physics Radiobiology and Radiation Protection, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Ali
Shabestani Monfared
Cancer Research Center, Babol University of Medical Sciences, Babol, Iran
author
Ebrahim
Zabihi
Cellular and Molecular Biology Research Center, Babol University of Medical Sciences, Babol, Iran
author
Zeinab
Abedian
Cellular and Molecular Biology Research Center, Babol University of Medical Sciences, Babol, Iran
author
Elahe
Bakhtiari
Student Research Committee, Babol University of Medical Sciences, Babol, Iran
author
Sajad
Borzoueisileh
Cellular and Molecular Biology Research Center, Babol University of Medical Sciences, Babol, Iran
author
text
article
2018
eng
Introduction:
Radiotherapy is still one of the main options for cancer treatment but it is in association with damage to normal cells as well as the tumor cells. To reduce the injury in normal cells we have evaluated the effect of 528 hertz sound after X irradiation in peripheral blood lymphocytes.
Materials and Methods:
in this study, peripheral blood was obtained from 25 healthy volunteers and blood lymphocytes were separated and divided into 4 groups: Ι) Control group, П) Radiation group, Ш) Radiation + Sound group ΙV) Sound group. To measure radiation effect on DNA, nuclear (DNA) damage rate was evaluated in all groups by the use of the comet assay.
Results:
The obtained data revealed that DNA damage rate in radiation group (190±45) is significantly higher than control (137±32), Sound (152±29). But, the difference of DNA damage in control with sound and also radiation+sound groups was not statistically significant.
Conclusion:
The results indicating that 528 hertz sound could induce radiation damage but when it will be combined with X radiation, the DNA damages of X-rays in peripheral blood lymphocytes is not significantly different with control groups which indicate modulation of DNA damages and addresses the needs for further studies.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
93
93
https://ijmp.mums.ac.ir/article_12421_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12421
Paediatric Dose AssessmentToward Establishment of National Diagnostic Reference Levels for Digital Radiography Examinations in Iran
Behzad
Mohsenzadeh
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran TEL: 09120510601, E-mail: behzad.mohsenzadeh@sbmu.ac.ir
author
Mohammad Reza
Deevband
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran TEL: 09123044609, E-mail: mdeevband@sbmu.ac.ir
author
text
article
2018
eng
Introduction:
Paediatric patients deserve special attention because of the higher radiation risks compared with adults. The main purpose of this study is to determine patient dose and diagnostic reference level for Paediatric through Entrance Surface Dose (ESD) calculations in common X-ray examination and to establish Paediatric national DRLs in digital radiography in Iran.
Materials and Methods:
The study was performed on 5260 patients in 53 X-ray room. They are classified into four age groups, 0>1 year, 1>5 years, 5>10 years and 10>15 years old. Skull (PA), Skull (Lat), Chest (PA), Chest (Lat), Pelvis(AP), Abdomen (AP) digital X-ray examination is done for them. The dosimetry protocol in this study was indirect method to measure Entrance Surface Air Kerma (ESAK). The X-ray tube output for each equipment is measured using RTI solid state detector (Model Barracuda). Finally, the third quarter determined diagnostic reference level.
Results:
Based on the results of this study, national diagnostic reference levels were established: for example, for age group 0 to 1-year-old: 0.51 mGy for Skull(AP/PA), 0.46 mGy for Skull(Lat), 0.11 mGy for Cervical spine(AP), 0.11 mGy for Cervical spine(Lat), 0.06mGy for Chest(PA), 0.08 mGy Chest(Lat), 0.15 mGy for Thoracic spine(AP), 0.26 mGy for Thoracic spine (Lat), 0.48 mGy for Lumbar spine (AP), 0.74 mGy for Lumbar spine(Lat), 0.47 mGy for Pelvis (AP) and 0.47 mGy for Abdomen (AP).
Conclusion:
This article has determined wide variations in radiation dose of x-ray examinations among hospitals in Iran. Application of a diagnostic reference levels (DRL) could be a optimization procedure for reducing patients dose. The survey reveals significant variations in the radiological practices.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
94
94
https://ijmp.mums.ac.ir/article_12422_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12422
Assessment of patients’ entrance skin and effective dose in a mathematical human phantom for the most common interventional radiological examinations
Bijan
Hashemi
Ph.D., Associate Professor, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Salar
Bijari
M.Sc. Graduate, Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Hossein
Ghanaati
Ph.D., Professor, Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran.
author
Mohsen
Bakhshandeh
Ph.D., Associate Professor, Department of Radiology, Faculty of Medical Sciences, Shahid Beheshti University, Tehran, Iran.
author
text
article
2018
eng
Introduction:
Nowadays, we are witnessing an exponential use of interventional radiology techniques in different communities. After CT, interventional techniques are the second factor of increasing patients’ doses in different societies. Measuring patient doses from aforementioned methods has been recommended by many radiation protection professional organizations such as ICRP and IAEA. Our aim was to measure/calculate the patients’ entrance skin and also necessary parameters required to estimate relevant effective doses for common diagnostic and therapeutic interventional radiology examinations.
Materials and Methods:
After reviewing and analyzing interventional radiology examination data in an imaging center of a public hospital over 6 months, five most commonly used examinations, including cholangiography, chemoembolization liver, uterine fibroids embolization, bile duct stenting and coronary angiography and brain embolization were selected for the dose measurements/calculations. For each examination, 50 patients were selected and their skin doses were measured using TLDs. Effective doses resulted from these examinations were also calculated by using the Monte Carlo based PCXMC software for an average human phantom.
Results:
The average entrance skin dose measured for the patients undergoing cholangiography, chemoembolization liver, uterine fibroids embolization, bile duct stenting and coronary angiography and brain embolization examinations were: 57, 141, 447, 241, 587 mGy and their estimated effective doses were 3.5,11, 31, 15.5, 10 mSv respectively. As expected, the patient doses in interventional radiology examinations varied, since the amount of doses depends on many factors including the complexity and difficulty of interventional procedures, operators’ experience and skill, and patients’ weight.
Conclusion:
In interventional radiology examinations a small field of view is used. Hence, appropriate voltage potentials and pulse durations must be used to reduce effective doses while achieving highest image qualities (resolution, contrast-to-noise ratio, and signal to noise ratio).
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
95
95
https://ijmp.mums.ac.ir/article_12423_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12423
Design and Fabrication Process of CT number Linearity and Homogeneity Phantom CT Scan
Behzad
Mohsenzadeh
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
author
Mohammad Reza
deevband
Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Evin, Tehran, Iran
author
text
article
2018
eng
Introduction:
One of the most valuable goals of phantoms, replacing with human goals in the field of research and quality control of diagnostic X-ray systems. There are various algorithms and methods for obtaining Homogeneity and CT number linearity for CT scan device. One of the most famous of these methods, the method is to use a uniform and homogeneous environment to compute Homogeneity and as well as the use of different materials with different densities to calculate CT number linearity. Therefore, a phantom was invented for a simple and fast calculation of Homogeneity and CT number linearity parameters for CT scan devices.
Materials and Methods:
Construction of Phantom CT number Homogeneity:
To make this phantom has been used CNC three-axis machine model 2000. First, an acrylic tube is cut with an internal diameter of 154 mm and an external diameter of 160 mm and a length of 30 mm. Then two acrylic disks are cut with a diameter of 154 mm and a thickness of 5 mm. In the middle of one of these disks hole is created a 20 mm diameter, which is filled with a plastic screw. Then these two acrylic disks are attached to the beginning and end of the tube.
Construction of Phantom CT number linearity:
For make this phantom has been used CNC three-axis machine model 2000. Using this device, the PE (Polyethylene), PMMA (Acrylic), PTFE (Teflon), Air, PS (Polystyrene) and PA (Polyamide) rods are cut in 25 mm and 25 mm in length. Then an acrylic disk is cut diameter of 154 mm and a thickness of 5 mm.
Results:
This phantom was tested for various CT scan devices. The results obtained from this phantom are equal to the external samples. The CT number Linearity chart obtained from this phantom corresponds to the CT number Linearity Phantom Pro-CT chart.
Conclusion:
This phantom has much less weight than other phantoms. The amount of material used in this phantom is greater than the other similar phantoms. The price of this phantom is very low compared to similar samples. In this phantom, Homogeneity and CT number linearity are calculated with higher precision and more points. Also, this phantom can be used to calculate noise.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
96
96
https://ijmp.mums.ac.ir/article_12424_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12424
Diagnosis of patients with Parkinson's disease using quantitative susceptibility mapping
Ahmad
Mohammadbeigi
MSc Student of Medical Physics, Students research committee, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Vahid
Shahmaei
MSc Candidate for Medical Imaging (MRI), Radiology Technology Dept., School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Friborz
Faeghi
Associate Professor, Radiology Technology Dept., School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Hassan
Hashemi
Professor of Radiology, Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran.
author
Farzad
Ashrafi
Associate Professor of Neurology, Functional Neurosurgery Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Parkinson'sdisease isassociated withirondeposition in the brain. The T2-weighted imaging, T2* mapping, R2 mapping and Quantitative Susceptibility Mapping (QSM) are three
common methods to evaluating the iron deposition in brain. Among three methods the QSM is more sensitive than others. Few studies have been used QSM for evaluating the iron deposition in the basal ganglia of patients with Parkinson's Disease (PD). Therefore, our aim was to evaluate the amount of iron deposition in the basal ganglia using QSM and determination the diagnostic value of this method; Also we evaluated the relationship between the QSM with age and stage of the disease.
Materials and Methods: Thirty patients categorized in three different stages using Hoehn and Yahr tests. The number of 8, 11 and 11 patients were considered for stage 1, stage 2 and
stage 3, respectively. Fifteen healthy subjects were considered as control group. MRI
sequences were performed using SIEMENS 3T scanner. The SPIN (Signal Processing in NMR)
software was used to processing and analyzing the images. The QSM was measured in all
basal ganglia (Red Nucleus, Substantia Nigra, Caudate, Globus Pallidus, Putamen, and
Thalamus) separately. The SPSS 18 (SPSS Inc., Chicago, IL) used for analyzing the data.
Results: There was a significant difference (P-value<0.001) for QSM in the Red Nucleus,
Substantia Nigra and Globus Pallidus nuclei between two patient and control group. The
relationship between disease stage with QSM was significant in Red Nucleus (RN), Substantia
Nigra (SN) and Globus Pallidus (GP) nuclei (P-value<0.001). Correlation of QSM with age was
not significant in any of the nuclei. The accuracy of QSM was 98.0, 86.7 and 88.9 percent for
SN, RN and GP. The specificity of QSM was 93.3, 100.0 and 86.7% for SN, RN and GP; Also the
sensitivity was 100.0, 80.0 and 90.0 for SN, RN and GP, respectively.
Conclusion: Using QSM in RN, SN, and GP nuclei can help diagnosis and staging of patients
with Parkinson's disease. Future studies with emphasis on the disease stage using larger
sample size can be helpful in evaluation the different sub-parts of these nuclei.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
97
97
https://ijmp.mums.ac.ir/article_12425_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12425
The Effect of FEW Scatter Correction Method in In-111 Imaging
Mahsa
Noori-Asl
Department of Physics, Faculty of Basic Science, University of Mohaghegh Ardabili, P.O. Bax 179, Ardabil1. Department of Physics, Faculty of Basic Science, University of Mohaghegh Ardabili, P.O. Bax 179, Ardabil
author
somayeh
Sotoudeh
Department of Physics, Faculty of Basic Science, University of Mohaghegh Ardabili, P.O. Bax 179, Ardabil
author
text
article
2018
eng
Introduction:
In nuclear medicine imaging, detection of the scattered photons along with the primary photons is one of the major problems that can lead to a decrease in ddiagnostic accuracy. Therefore, use of a suitable scatter correction method can help to improve of the image quality and increase of diagnostic accuracy. The aim of this study is evaluation of five energy window (FEW) method for scatter correction of In-111 imaging that can be used for evaluation of brain tumor.
Materials and Methods:
For evaluation of the scatter correction method, six cold (without activity) spheres with diameters 3.2, 2.6, 2, 1.6, 1.3 and 1 cm placed in the water-filled cylindrical phantom is simulated by SIMIND Monte Carlo simulation program (version 6.1). The scatter correction is performed by setting five energy window in In-111 energy spectrum: two 20% photopeak energy window centered on E1=171 keV and E2=245keV, and three narrow energy windows, including two 8% energy window centered on lower- and upper-energy limits of the first photopeak energy window, and a 8% energy window centered on lower-energy limit of the second photopeak energy window. To evaluate the performance of the scatter correction method, the image contrasts and signal-to-noise ratios were calculated for six cold spheres.
Results:
The results obtained in this study are shown that the relative increase of the image contrast of the cold sphere 1, 2, 3, 4, 5 and 6 is about 31.3, 34.16, 26.73, 4.50, 2.48 and 5.76%, respectively. The improvement in the image contrast of sphere 6 is larger than that of sphere 5 that shows the nonuniform performance of this scatter correction method. The relative noise of background for the uncorrected and the corrected images is 0.031 and 0.0878, respectively, that shows the scatter correction by the FEW method results in the increase of the image noise significantly.
.
Conclusion:
The results of this study show that the FEW scatter correction method improves the image contrasts of six cold spheres nonuniformly with a significant increase in the level of noise
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
98
98
https://ijmp.mums.ac.ir/article_12426_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12426
Construction of an Equivalent Chest Homogeneous Phantom for Evaluation of Image Quality in Pediatric Radiography
Fereshte
Rahmani
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
author
Behzad
Mohsenzadeh
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
author
Zeinab
Kaveh
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
author
Mohammad Reza
Deevband
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran TEL: 09123044609, E-mail: mdeevband@sbmu.ac.ir
author
Leila
azimi
Departeman of imaging of Velayat hospital, University of medical science, Qazvin, Iran
author
text
article
2018
eng
Introduction: The purpose of this study is to build homogeneous equivalent phantom chest in order to provide the necessary ability for checking the image quality in radiographic tests in four age groups of children in terms of the most recent age group categorization ICRP103. This phantom provides the features of weakness and discrepancies similar to body and can be considered as a good alternative for the geometrical body equivalent Phantom. Materials and Methods: This geometrical body equivalent phantom has been employed in order to measure the absorbed dose using Monte Carlo calculation code. Using this phantom in Monte Carlo space in which x-ray tube system has been simulated as well makes it possible to analyze the weaknesses and x-ray discrepancies. The Phantom is made of Plexiglas. Results: Validity of the tests with lower than 5% error, deep dose in Monte Carlo and the experimental space as well collectively confirms the simulator program. After the process of simulation, the homogeneous phantoms chest equivalent in children were produced with different thicknesses for different age groups. Simulated as well makes it possible to analyze the weaknesses and x-ray discrepancies. Conclusion: The phantom designed in this study can be used to evaluate the dose of children in different age groups, Also, using image quality control tools such as contrast, resolution, etc. in this phantom can be used to evaluate the parameters of the image quality in the actual condition of the patient's body. In this study, An attempt was made to provide a new method for the construction of a chest equivalent phantom that would include all age groups.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
99
99
https://ijmp.mums.ac.ir/article_12427_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12427
Design and Fabrication Process of MTF Phantom CT Scan
Behzad
Mohsenzadeh
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran TEL: 09120510601, E-mail: behzad.mohsenzadeh@sbmu.ac.ir
author
Mohammad Reza
Deevband
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
author
text
article
2018
eng
Introduction:
One of the main steps in the optimization process in diagnostic imaging is the quality control of radiology devices. The usual method of CT scan calibration is used of a phantom. The phantom created a certain weakening for the radiation through which it passes. One of the most suitable methods for quantitative analysis of the resolution and contrast in CT scan images is to calculate MTF chart. Modulation in imaging is means contrast and the transfer function to the concept of the contrast ratio of the output to the contrast of the input system. The modulation transfer function of an imaging system is reflecting the contrast of the system at various space frequencies. The aim of this study is created phantom MTF for a CT scan.
Materials and Methods:
For phantom design, firstly, the number of pairs of lines required for CT scan images was evaluated and 2 to 14 LP/cm were selected for this phantom. Then, to create these pair of lines, you need a metal with a low atomic number until the amount of artifact decreases that aluminum was selected in this regard. Then using the AutoCAD software, the MTF calculation tool was designed as L-shape. Finally, the MTF calculation tool was combined into the groove created in the acrylic disk using the LOEXAL glue.
Results:
This phantom was tested for various CT scan devices. The results obtained from this phantom are equal to the external samples. The MTF chart obtained from this phantom corresponds to the MTF Phantom Pro-CT chart.
Conclusion:
This phantom has much less weight than other phantoms. The thickness of these lines is high and it can be captured in a slide CT scan of all the lines. In this phantom, the modulation function or MTF is calculated with high precision and more points. This phantom can be used for limiting spatial resolution.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
100
100
https://ijmp.mums.ac.ir/article_12428_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12428
Evaluation of the accuracy of calculated dose with the EPL and ETAR algorithms using thorax CIRS phantom.
Mansour
Zabihzadeh
Associate Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Syyed Mohammad
Hoseini
Associate Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Sasan
Razmjoo
Assistant Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Sholeh
Arvandi
Assistant Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mozafar
Naserpour
PhD student, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Azizollah
Rahimi
PhD student, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction: Each treatment planning algorithm has some errors in dose calculation. Particularly these errors are more pronounced in the heterogeneous regions. It is recommended for each set of radiation data and algorithm subtle deliberation done regarding dose calculation accuracy. Knowing the amount of error in dose calculation will result in a fairly accurate estimate of the actual absorbed dose to the tumor. Also, if the errors have a certain trend, the correction coefficients can be applied to emend the dose. There are limited reports that have examined the algorithm in their health center. This study aimed to evaluate the EPL and ETAR algorithms in radiation dose calculation using thorax CIRS phantom.
Materials and Methods: In this empirical study TEC-DOC 1583 guideline provided by IAEA was used. Experimental measurements were obtained using an ionization chamber at the recommended points according to above instructions for 6 and 18 MV energies. The values of the measurements were compared with the values obtained from the calculation of the EPL and ETAR algorithms using acceptance criteria specified in the instruction. A total of 31 measurements and calculations were obtained for each algorithm with a specific energy. Due to the small number of measurable points in the phantom, for each test, difference between the measurement and calculation was normalized to the reference point of each test.
Results: In the EPL algorithm for 6 MV energy, the calculations were in agreement with measurements for 27 dose points and differences between measurements and calculations ranged from 0.1% to 10.4%. For 18 MV energy, the calculations were in agreement with measurements for 21 dose points and differences between measurements and calculation ranged from 0.4% to 13%. In ETAR algorithm for 6 MV, calculations were in agreement with measurements for 21 dose points, and differences between measurements and calculations ranged from 0.1% to 9%. For 18 MV, the calculations were in agreement with measurements for 17 dose points and differences between calculations and measurements ranged from 0% to 11%.
Conclusion: For the EPL algorithm, compared with the ETAR algorithm, more dose points were agreed with acceptance criteria. Although the numerical values of the errors in the ETAR algorithm were 1 to 2 percent less than the EPL algorithm. The greatest error occurs when calculations made in low density lung tissue with inhomogeneities or in high density bone. Errors were larger in shallow depths. Overall, the error in higher energy was more than low energy beam.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
101
101
https://ijmp.mums.ac.ir/article_12429_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12429
Improvement of dose delivery with loading of tumor with gold nanoparticles in orthovoltage radiotherapy
Mansour
Zabihzadeh
Associate Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mohammad Ali
Behrooz
Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mehdi
Ghorbani
Assistant Professor, Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Courtney
Knaup
Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, USA.
author
Mozafar
Naserpour
PhD Student, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Toktam
Moshirian
PhD Student, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction: To enhance the dose to tumor, the use of high atomic number elements has been proposed. Objective: The aim of this study is to investigate the effect of gold nanoparticle distribution on dose enhancement in tumor when the tumor is irradiated by typical monoenergetic X-ray beams by considering homogeneous and inhomogeneous distributions of gold nanoparticles (GNPs) in the tumor.
Materials and Methods: Methods: MCNP-4C Monte Carlo code was utilized for the simulation of a source, a phantom containing tumor and gold nanoparticles with concentrations of 10, 30 and 70 mg Au/g tumor. A 15 cm ×15 cm ×15 cm cubic water phantom was irradiated with a small planar source with four monoenergetic X-ray beams of 35, 55, 75 and 95 kV energy. Furthermore, tumor depths of 2.5 cm, 4.5 cm and 6.5 cm with homogeneous and inhomogeneous distributions of GNPs were studied. Each concentration, photon energy, tumor depth and type of distribution was evaluated in a separate simulation.
Results: Results have shown that dose enhancement factor (DEF) in tumor increases approximately linearly with the concentration of GNPs. While DEF has fluctuations with photon energy, 55 keV photons have the highest DEF values compared to other energies. While DEF has relatively the same values with tumor located at various depths, inhomogeneous distribution of GNPs has shown different results compared with the homogeneous model.
Conclusion: Dose enhancement can be expected with tumors in radiotherapy with low energy X-rays. Inhomogeneous model is recommended for the purpose of dose enhancement study because it mimics the real distribution of GNPs in tumor.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
102
102
https://ijmp.mums.ac.ir/article_12430_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12430
Blood Brain Barrier Disruption by Focused Ultrasound and Microbubbles: A Numerical Study on Mechanical Effects
Zahra
Khodabakhshi
Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
author
Hossein
Ghadiri
Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Microbubbles are widely used as contrast agent in diagnostic ultrasound. Recently they have shown good potential for applications in the therapeutic field such as drug delivery to the brain. Recent studies have shown focused ultrasound in conjunction with injected micro-bubbles could temporarily disrupt blood-brain barrier and let therapeutic agents transport into the brain tissue. The main aim of current study was to investigate, the interactions between ultrasonic acoustic field and microbubbles and the resultant mechanical effects on microvessels.
Materials and Methods: In this study, we have used numerical approach to simulate microbubble confined in a microvessel filled with viscose fluid as blood. In the main stream of our study two crucial equations have been solved: equation of bubble oscillation on the bubble surface in an ultrasonic acoustic field (R-P equation), and equations of mass conservation and continuity (Navier Stokes) in fluid domain. Microbubble radius change, subjected to ultrasonic wave, and the force-fluid coupling which cause high velocity gradient and subsequent exertion of shear stress on interior vessel wall have been calculated. In this study microvessel considered as a viscoelastic solid. Acoustic pressure amplitude has been varied between 1.5P0 and 5P0 (P0 is hydrostatic pressure in fluid, P0~ 104.6kPa) with a constant frequency (f=1MHz). Then at a constant pressure of 2.5P0 acoustic frequency has been changed between 1 and 6MHz. Shear stress and transmural pressure, two important metrics for mechanical effects and vessel damage, have been calculated for each case.
Results: The results obtained from the preliminary analysis of simulation study demonstrate that by increasing acoustic pressure both shear stress and transmural pressure increase linearly between 4-20 and 300-650kPa respectively. When the acoustic pressure reached the value 5P0 vessel ruptured and at this point, our simulation was stopped. This study has shown that by increasing acoustic frequency, relative difference of bubble radius, increase to%66 and then decrease to %12. In this case, shear stress and transmural pressure reached almost to a maximum of 10 and 450kPa respectively.
Conclusion: The present study has gone some way towards enhancing our understanding of interaction between the acoustic field and micro bubbles. Mechanical effects on vessel wall are pressure and frequency dependant and it’s important to find a threshold for acoustic pressure that below it vessel damages won’t occur. This study has identified threshold for acoustic pressure is about 0.45P0. Also, it is very important to consider microbubbles resonance frequency at which maximum amplitude of oscillation and mechanical effects occur.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
103
103
https://ijmp.mums.ac.ir/article_12431_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12431
The effect of Ag NPs co-exposure with UVC irradiation on TK6 cells viability
Tahereh
Zare
Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
author
Reza
Fardid
Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction:
Because of advancement in nanotechnology, the use of Ag Nanoparticles (NPs) was increased in a wide range of area. Studies that were done in recent years demonstrated that Ag NPs can induce cytotoxicity in cells. One of the parts of UV radiation of sun is UVC (200 – 280 nm) that has antimicrobial effect. Since the effect of simultaneous use of NPs and UVC are still not well determined, so in the present study, we investigate the effect of Ag NPs and UVC irradiation on TK6 cell viability.
Materials and Methods:
To do this study, the human lymphoblastoid TK6 cell line was purchased from the American Type Culture Collection (ATCC® CRL-8015TM). Ag NPs were obtained from the US Research Nanomaterials Inc. (Stock#: US1038). According to the manufacturer, the Ag NPs were ~ 20 nm (TEM image).
The effect of co-exposure of Ag NPs and UVC was investigated by a MTT assay. TK6 cells were cultured in 96 well culture plate (2.5×104 cell/ well). The cells were treated with Ag NPs (0, 5, 10 and 15 μg/ml in each well) and UVC irradiation (1mW/ cm2). Following exposure, cells were incubated with MTT solution (5 mg/ml, SIGMA ALDRICH, M2128; USA). After 4hrs, MTT solution was then discarded, and 100 µl of DMSO was added to each well. Cell viability was calculated as a percentage of the control groups.
Results:
The MTT assay results show that with increasing in Ag NPs concentration the viability of cells was reduced. Also when cells were co-exposed with Ag NPs and UVC a significant reduction on cell viability was observed in all NPs concentration.
Conclusion:
Results of this study showed a synergistic decrease in cell viability post Ag NPs and UVC irradiation of cells in comparison with control groups.
In summary, co-exposing human lymphoblastoid TK6 cells to UVC after treatment with different Ag NPs concentration, can induce dose dependent cellular toxicity.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
104
104
https://ijmp.mums.ac.ir/article_12432_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12432
Calculation of wedged dose distributions using an analytical method
Mahdie
Behjati
Nuclear engineering unit, Department of Energy Engineering, Sharif University of Technology, Tehran, Iran.
author
Mostafa
Sohrabpour
Nuclear engineering unit, Department of Energy Engineering, Sharif University of Technology, Tehran, Iran.
author
Seyed Pezhman
Shirmardi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran.
author
Mohammad Amin
Mosleh-Shirazi
Physics Unit, Department of Radiotherapy and Oncology, and Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
Fathollah
Bouzarjomehri
Medical Physics Unit, Department of Medical Physics and Environment Health, Shahid Sadoghi University of Medical Sciences, Yazd, Iran
author
text
article
2018
eng
Introduction:
Wedge filters are used in radiotherapy to modify photon beam and improve dose uniformity in the target volume. Determination of wedge dose distribution is important to improve treatment planning accuracy. The utilization of treatment planning software to obtain dose distribution is not always available. In this work an analytical model has been developed to calculate wedge dose distribution and the resulting isodose curves.
Materials and Methods:
The analytical method can be calculated the dose at any point (off axis and in axis) and for each wedge angle and field size with a given dose at any point of phantom. The calculated doses were converted to isodose curves with MATLAB software and validated with Elekta motorized wedge (MW) and Cobalt physical wedge (PW). Isodose wedge curves were measured using a 2-D profiler detector for Cobalt unit and a diode detector for Elekta linac.
Results:
The mean difference between analytical isodose curves and measurements for Elekta motorized wedge was 1.8% and for Cobalt physical wedge was within 3%. The differences were in agreement with ICRU criteria.
Conclusion:
The analytical method can be used as a fast and handy method for calculating dose at any off axis points and depth dose.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
105
105
https://ijmp.mums.ac.ir/article_12433_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12433
Dose GRID increase the unwanted photoneutron dose to the patients in GRID therapy?
Nahid
Chegeni
Department of Medical physics, Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Amir Hossein
Karimi
Department of Medical physics, Jundishapur University of Medical Sciences, Ahvaz, Iran
Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction:
GRID therapy is a treatment modality in which a high dose of radiation in a single fraction is given to the tumor. This technique previously was used to treat bulky tumors with orthovoltage beams. Recently, studies have been conducted to suggest that GRID therapy with megavoltage photons can be useful in palliative treatments. On the other hand, there has always been concern about the unwanted production of photoneutrons by LINAC head in treating with energies above 10 MeV. This problem is more worrying in modern radiotherapy techniques in which more monitor units are used, such as Intensity Modulated Radiotherapy (IMRT) and GRID therapy. So far, the effect of the GRID on photoneutron contamination has not been completely studied. While in terms of radiation protection, it is important to evaluate the GRID effect on photoneutron dose to the patients. In addition, one of the limitations of neutron dosimeters is that even with the most precise tools, one cannot achieve uncertainty less than 10% in measurements, while by Monte Carlo (MC) simulations, these limitations can be removed very much and a more accurate estimate of neutron dose can be provided.
Materials and Methods:
In this study, using the Monte Carlo code MCNPX, the main components of the Varian Clinac 2100 C/D were simulated. For 4×4, 10×10, and 20×20 cm2 field sizes, the Percentage Depth Dose (PDD) and profile curves were calculated and benchmarked with the measured data. After the model tuning, the neutron source strength of the LINAC (Q), the distributions of ambient dose equivalent (H*(10)) of neutrons were calculated on the treatment table for 10×10 cm2 field size, in both cases: with/without a typical GRID.
Results:
Our results indicate that, the GRID increases the neutron source strength by only 0.3% and also, one can see that the GRID reduces the ambient dose equivalent of neutrons at the isocenter (IC) 48.9%. In addition the average reduction in the ambient dose equivalent of neutrons is 38.5% at the intervals of less than 30 cm from the IC.
Conclusion:
It was found that in GRID therapy technique compared to conventional radiotherapy, the neutron dose on the treatment table is dramatically reduced. Therefore; there will be no concern about the increase of unwanted neutron dose in GRID therapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
106
106
https://ijmp.mums.ac.ir/article_12434_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12434
Transcranial near-infrared phtobiomodulation causes anti-depressive and anti- anxiety effects in mice model of depression
Emad
Eshaghi
Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz 51666, Iran
Department of Medical Physics, Tabriz University of Medical Sciences, Tabriz 51666, Iran
author
Saeed
Sadigh-Eteghad
Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz 51666, Iran
author
Gisou
Mohaddes
Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz 51666, Iran
author
Reza
Meinaghizadeh Zargar
Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz 51666, Iran
Department of Medical Physics, Tabriz University of Medical Sciences, Tabriz 51666, Iran
author
Seyed Hossein
Rasta
Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz 51666, Iran
author
text
article
2018
eng
Introduction:
Depression is a common psychiatric disorder and about one in five people experience depression during their lifespan. Despite the anti-depressive effects of drug therapy, problems such as non-targeting and dose-resistant lead to more effective approaches. Transcranial Photobiomodulation (TPBM) or transcranial low-level laser (TLLL) therapy is a novel and neuroprotective approach which its therapeutic potential has been experimentally examined for central nervous system disorders such as stroke, traumatic brain injury, Alzheimer disease, and Parkinson disease. In this safe and non-heating approach, the damaged and troubled brain areas are irradiated transcranially by near- infrared (NIR) and red (600-1100 nm) low power (less than 500 mW) diode lasers, lasers, and light emitting diodes. The functional mechanism in this approach is that NIR and red photons are absorbed by photo-receptors such as cytochrome c oxidase (COX) and then a number of biological processes including mitochondrial respiratory chain and ATP synthesis are accelerated and cause modulatory effects on nerve cells activities. The main goals of the current study are to examine the anti-depressive and anti-anxiety effects of NIR TPBM by behavioral tests including open field test (OFT), and elevated plus maze (EPM) test in mice model of depression.
Materials and Methods:
Thirty-three (eight- to ten-week-old) BALB/c male mice were used for all experiments. Mice were obtained from animal lab of Tabriz University of Medical Sciences. One week before the experiments began, all animals were housed in standard conditions of dark/light cycle (12h/12h), humidity (40-50%), and temperature (20-23 °C). Then mice were divided into three groups (11 per group): control, stress (sham), and near-infrared treated (NIRT) groups. To induce stress, sham and NIRT mice were trapped in a 50 ml polypropylene cylinder for three continuous weeks (3h/day). NIRT group received simultaneous laser treatment with stress induction, however, laser probe was placed on the skull of sham mice, but irradiation was not done. For TPBM therapy a GaAlAs diode laser (810nm, 10 Hz, 88% duty cycle, and power density of 4.75 J/cm2) was used and irradiation was done on odd days and continued for three weeks (nine treatment sessions in total). At each session of laser therapy, 8 J/cm2 dose of NIR light was delivered to the brain cortex of NIRT mice. At the end of stress procedure, behavioral tests including OFT, and EPM were performed to evaluate the anti-anxiety and anti-depressive effects of TPBM and The underlying variables were calculated: time spent in the center square of the OFT, and both percentage of time spent in the open arms (%OAT), and percentage of open arm entries (%OAE) in the EPM.
Results:
Sham mice which underwent to stressful conditions showed significantly (p<0.001) less tendency to spent time in the center part of the OFT in comparison to control group. Furthermore, %OAT and %OAE were significantly (p<0.001) declined in the sham group. The bad effects of stress procedure declined by TPBM so that NIRT mice indicated a more significant (p<0.01) tendency to spent time in the center square of the OFT. In addition,
%OAT (p<0.0001) and %OAE (p<0.001) significantly increased in NIRT group.
Conclusion:
In this study, OFT and EPM were performed to examine the anti-depressive and anti-anxiety effects of TPBM, respectively. Our results indicated that TPBM decreased depressive-like behaviors and NIRT mice significantly tended to spend more time in the middle part of the OFT. In addition, %OAT and %OAE were significantly improved by TPBM which indicated a reduction in anxiety-like behaviors. As a whole, this study indicates that TPBM is a novel approach to depression improvement which can enhance depressive- and anxiety-like behaviors.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
107
107
https://ijmp.mums.ac.ir/article_12435_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12435
Design, Construction and Evaluation of an Anthropomorphic Head Phantom for Assessment of Image Distortion in Stereotactic Radiosurgery Planning Systems
Sadegh
Shurche
Physics and Medical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
author
Nader
Riahi Alam
Physics and Medical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
author
Mohamad
Yousefi Sooteh
Medical Physics Department, Tabriz University of Medical Sciences, Tabriz, East Azerbaijan, Iran
author
text
article
2018
eng
Introduction:
In recent years, the use of magnetic resonance (MR) images in radiation treatment planning has drawn considerable attention. However, although the extent of a tumor can be determined in great detail on MR images, the geometric accuracy of these images is limited by distortions stemming from the inhomogeneity of the static background magnetic field, the nonlinearity of the applied gradient magnetic fields, the magnetic susceptibility of the imaged tissues, and chemical shift artifacts. Our goal is to design and construct a new Anthropomorphic Head Phantom for Assessment of Image Distortion in Treatment Planning Systems.
Materials and Methods:
In this study, CT scan images of head were transferred to the Mimic software (Mimics® Innovation Suite). Using this software, the skull texture was removed and a hollow layer formed between the bone tissue in which the bone tissue would be equivalent to the material. Then fabricated it with a 3D printer and used K2HPO4 (as bone). we designed a new 3D grid containing 13,824 reference features (control points) with AutoCAD software, fabricated it with a 3D printer, and filled it with gels that include nickel-doped agarose, sucrose, urea, and sodium chloride (as soft tissue) then placed this grid Inside the head phantom. The phantom is supplied with specially designed pads that allow fixation with any stereotactic frame or mounting for end-to-end testing. This phantom was tested on the Siemens 3 Tesla Prisma MRI model using a 64-channel head coil. We used imaging from a six-slice CT scan (Siemens) as a reference and matched the reference features in the MRI images with the CT-scan images. To achieve this, we used a three-dimensional reference feature model. Reproducibility on the phantom was investigated with three different imaging sessions per day for three different days.
Results:
The CT numbers and relative electron density of the gels closely resembled those of real tissue and T1 and T2 of the gels closely resembled those of real tissue. The geometric distortion in the 3D results was found to be due to field non-uniformity and nonlinearity of the gradients and its reproducibility. The mean Euclidean distance error for MRI volume was less than 0.9 mm. The maximum Euclidean error was 1.3 mm. Distortion in the whole volume is pronounced exclusively at the edges of the magnetic field.
Conclusion: As with other investigations carried out in our work, the amount of distortion in the middle of the field was less than at its sides. This phantom can be used to check Image Distortion in Treatment Planning Systems.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
108
108
https://ijmp.mums.ac.ir/article_12436_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12436
Characterization of electron density of the real tissues for radiotherapy planning using dual energy algorithm and stoichiometric calibration method
Mohammad J
Thahmasebi Birgani
Department of Medical Physics, Faculty of medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Maziyar
Mahdavi
Department of Medical Physics, Faculty of medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
author
Mansour
Zabihzadeh
Department of Medical Physics, Faculty of medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mehrzad
Lotfi
Medical Imaging Research Center and Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran.
author
Mohammad A
Mosleh-Shirazi
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
Physics Unit, Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran.
author
text
article
2018
eng
Introduction: Characterization of the relative electron density (𝜌e) of the body tissues is routinely provided by scanning the commercial phantom like RMI 467 at 120 kilovoltage (kVp) in radiotherapy planning. Recent studies showed that the calibrating Hounsfield Unit–
𝜌e curve could be obtained linearly using dual energy computed tomography (DECT) algorithm in commercial phantom like RMI 467. The aim of this study was to produce a more accurate calibrating HU–𝜌e curve by constructing an in- house phantom and applying dual energy algorithm.
Materials and Methods: An in-house water filled phantom (33cm diameter) was made including ten water solutions plus composite cork as tissue substitute materials (TSM), and scanned at four kVps by multi-detector four slice CT. The dual energy algorithm was applied to two combination scans (80-140 and 100-140 kVp) and the linear HU–𝜌e curves were produced. The stoichiometric method reproduced the HUs of 31 real body tissues, that their compositions are available in ICRU-46 report. The HU–𝜌e curves for both kVp combination scans were produced. The t-test and compare means were performed between the mean and standard deviation of the relative and absolute differences (%) of the 𝜌e of 31 ICRU real tissues calculated for 120 kVp and both kVp combination scans in the current and previous studies, respectively
Results: Applying an energy subtraction algorithm mitigated the 𝜌e calculation error of real tissues. The mean and standard deviation of the relative difference between the 𝜌e of 31 ICRU tissues (–0.23±1.89) were statistically significant compared with the mean and standard deviation of the 30 ICRU tissues (0.80±1.58), which extracted from the RMI 467 phantom at
120 kVp in previous study (p<0.024). The mean and standard deviation of absolute differences of the calculated 𝜌e of the 31 ICRU tissues at 100-140 kVp combination scans (0.14±0.11) compared to previous study using 100-140kVp scan (0.30±0.40) in a second generation dual source CT, were statistically significant (P<0.035).
Conclusion: The stoichiometric calibration method and closeness of the 𝜌e of 11 TSMs can result in statistically significant smaller discrepancies in calculating the 𝜌e of real tissues at
120 kVp, compared to the previous studies with RMI 467. The stoichiometric fitting parameters were highly affected by beam hardening artifacts and image noise, especially at 80 kVp. Applying the energy subtraction algorithm can offer further error mitigation in 𝜌e calculation of real tissues by spectral separation and reduction of beam hardening artifacts and noise in two kVp combination scans compared to previous studies. Therefore, a dual energy algorithm in combination with stoichiometry can be used to decrease errors in calculation of the 𝜌e of real tissues, and could be used for radiotherapy planning and material differentiation in clinical practice.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
109
109
https://ijmp.mums.ac.ir/article_12438_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12438
Dose distribution of protons and flux of secondary particles in breast proton therapy.
Fateme
Maroufkhani
Master, Department of Physics, Faculty of Basic science, Imam Khomeini international university, Qazvin, Iran
author
Seyed Mohammad Mahdi
Abtahi
Assistant Professor, Department of Physics, Faculty of Basic science, Imam Khomeini international university, Qazvin, Iran
author
text
article
2018
eng
Introduction: Proton therapy is newer therapeutic method for early stage breast cancer. Proton beams release most of their energy in the Bragg peak and then will be a rapid decline in their end. When protons interact with matter, produce secondary particles like neutrons and gammas, and these unwanted radiation has no beneficial effect and also is believed to increase the risk of secondary cancers, so it’s necessary to assess these secondary particles. Monte Carlo algorithm is the most accurate calculation method in the dosimetry. MCNPX is a modern, general purpose Monte Carlo code that were used to model the transport and interactions of particles in patient’s body, also is currently the most commonly used MC codes for proton therapy. In this study, calculated flux of secondary particles like neutron and photon in vital organs and dose distribution of Proton in energy range of 40 to 70 with 10 single step. Materials and Methods: Analytical phantom of the human body, ORNL used to create the input files and Protons as pencil beam modeled in front of left breast with energy of 40 to 70 MeV for covering the left breast, eventually Counting sensors for tracking the trajectory of secondary particles and provide the necessary data were used. Results: the dose distribution of protons shows they can have covered the exact shape of tumor with high accuracy and release most of their energy on it, so it’s best feature of proton therapy also flux of secondary particles shows the most important organs are Heart-left ventricle and left lung in left breast proton therapy because of the most flux of secondary particles reach to them. Conclusion: flux of secondary particles in vital organs shows that even though proton therapy is a good option Due to the favorable Bragg peak radiation and delivers high dose to a small volume of cancerous tissue while the healthy structures will be spared during proton radiation therapy and flux of secondary particles are low but they are not low enough to be negligible.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
110
110
https://ijmp.mums.ac.ir/article_12599_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12599
Gamma Radiation Measurement due to Natural Radioactivity in Hot Water Spring of Behbahan
Foad
Goli Ahmadabad
Lecturer, School of Medicine, Jiroft University of Medical Sciences, Jiroft, Iran
author
Behrouz
Rasuli
Lecturer, Department of Radiology, Behbahan School of Medical Sciences, Behbahan, Iran
author
Raheleh
Tabari Juybari
Lecturer, Department of Radiology, Behbahan School of Medical Sciences, Behbahan, Iran, Tel: 09163735965, Email: r.tabari@gmail.com
author
Susan
Ebam
Lecturer, Department of Environmental Health Engineering, Jiroft University of Medical Sciences, Jiroft, Iran
author
Meysam
Forouzi
Lecturer, Department of Radiology, Behbahan School of Medical Sciences, Behbahan, Iran
author
text
article
2018
eng
Introduction: Many people use hot water springs to treat some diseases, such as rheumatism, arthritis, and skin diseases, but they are unaware of the presence of natural radioactive substances that may be found in hot water springs. An effective way to understand the radiation risk of these elements are measuring the dose rate of radiation. In this study, for the first time, gamma dose rate has been measured at the hot water spring of the Garab village in Behbahan city.
Materials and Methods: To measure of gamma dose rate in the hot water spring and around it, 6 points were considered and the dose rate in these areas was measured using the RAS-110 Survey meter in four seasons of the year. The dosimeters were also placed at two heights of 5 cm and 1 m, and the dose rate was read and recorded for 20 minutes in any point.
Results: The measured absorbed dose rates in air ranged from 49 to 331 nGy/h, in hot water spring areas. The maximum high radiation dose rate was found nearby the principle hot water source (point 1) was measured at 331 nGy/h. The annual effective dose for this place was estimated to be 0.4 mSv.
Conclusion: The results of this study showed that the annual effective dose of natural gamma in the hot water spring is higher than the global average and there was a significant difference between the dose rates in different seasons. Also, the effect of height on the amount of radiation is negligible
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
111
111
https://ijmp.mums.ac.ir/article_12600_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12600
The Effect of Panoramic Radiography on the Diagnosis of Lesions in Dentistry and Its Effect on Cumulative Dose
Mohammad Rasoul
Tohidnia
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Rasool
Azmoonfar
MSc of Radiobiology and Radiation Protection, Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Setareh
Alikhani
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Fatemeh
Amiri
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Rajab
Ghanbari
Dentistry School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
text
article
2018
eng
Introduction: One of the most commonly used radiography methods for the diagnosis of oral and dental diseases is the panoramic radiography technique. This technique is widely used due to ease of implementation, extensive coverage, time and cost savings. Dental radiography, as a routine and appropriate test, accounts for about 33% of the total radiographic examination. However, information derived from radiography plays a major role in detecting lesions in dentistry, but it puts the patient at risk from the effects of ionizing radiation. This study was designed and implemented with the aim of investigating the lesions found in panoramic radiographies in patients referred to the Kermanshah Imaging Centers.
Materials and Methods: In this retrospective-descriptive cross-sectional study, 378 panoramic images were collected from Kermanshah Imaging Centers and assessed by the dentist. Data collection was done by completing a two-part checklist, consisting of 46 questions including demographic information, questions about the relative frequency of lesions found in panoramic images, including the existence, characteristics, and pathology types of lesion.
Results: According to the findings of this study, 56.6% of patients had a lesion. The most commonly found lesion was tooth decay (194 cases), which 92.4% of total radiographies with lesion and 51.3% of the total radiographs. The least damage was also in the case of tumoral jaw lesions (4 cases), which contained 1.9% of radiography with lesion and 1.1% of total radiographs. The highest rates of decay lesions, periodontal lesions, dwindle of bone crest and localized inflammatory lesions of the jaw lesions unilaterally and with a certain margin.
Conclusion: Altogether, the findings of this study showed that nearly half of the panoramic images did not show any lesion. This suggests that dentists should be more concerned about the unnecessary use of panoramic images about the overall assessment of the condition of the teeth and the evaluation of dental caries.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
112
112
https://ijmp.mums.ac.ir/article_12601_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12601
The Evaluation of Radio-sensitivity Effect of Hydroxyapatite Nanopartical on MCF-7 and Fibroblast Cell Line
Mitra
Soleimani
Student Research Commitee, Department of Medical physics, Radiobiology and Protection, Babol University of Medical Sciences, Babol
author
Fatemeh
Elmi
Department of Marine Chemistry, Faculty of Marine & Oceanic Science, University of Mazandaran, Babolsar, Iran
author
Ladan
Barari
Department of Marine Chemistry, Faculty of Marine & Oceanic Science, University of Mazandaran, Babolsar, Iran
author
Seyyed Hossein
Mousavie Anijdan
Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
author
Maryam Mitra
Elmi
Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
author
text
article
2018
eng
Introduction: Hydroxyapatite nanoparticles inhibit the growth of various cancer cells. The inhibitory effect of these nanoparticles on breast cancer cells of mcf7 has also been reported. However, no studies have been done on the effect of the hydroxyapatite nanoparticles on the radiation sensitivities of the MCF7 cell Line. Our goal in this study is to investigate the effect of cytotoxicity and radiation sensitization of hydroxyapatite nanoparticles on mcf7 and healthy fibroblast cells. In the concentration-dependent process, these nanoparticles greatly inhibit the growth of MCF7 cells compared to healthy fibroblast cells. the radio sensitivity effect of these nanoparticle was also found to be very high in MCF7 cells.
Breast cancer is the most common cancer in women. the most common treatment are chemotherapy and radiotherapy after surgery that both of these methods are associated with many side effects. also, many cancer cells show resistance to these two methods. So, researchers are looking for materials that are used to improve cancer with fewer side effects. According to recent advances in the field of nanotechnology, application of nanoparticles in medicine, in particular, the treatment of incurable diseases including cancer treatment, are considered. One of these nanoparticles is hydroxyapatite with the chemical formula, Ca10 (PO4) 6 (OH) 2. Hydroxyapatite is similar to minerals in bones and hard tissues, and has great compatibility with body (Harirchi, Kolahdoozan, et al., 2011). So, it could be used in the different biological and biomedical applications.
Materials and Methods: Materials used in this study include: MCF7 Cell Line، Fibroblast Cell، RPMI 1640، DMEM-High glucose، FBS، Pen/Strep، PBS، MTT، DMSO، Giemsa Stain، Etydiombrumid/Acrialorange، Methanol، Trypsin- EDTA، Isopropranol. In this study, the effect of cytotoxicity of hydroxyapatite nanoparticles on mcf7 and fibroblast cells was investigated using the MTT assay at concentrations (0، 12.5، 25،50، 100، 200 and 400µg/ml) of nanoparticles. The radiosensitivity effect of these nanoparticles on the cells was studied with the three methods: MTT assay، clonization and apoptosis assays
Results: The study of cytotoxic effects of hydroxyapatite nanoparticles on MCF7 and fibroblast cells by MTT showed that nanoparticles reduce the cell survival in the dose- dependent process and the cytotoxic effects of these nanoparticles are not time-depende. Investigating the effect of hydroxyapatite nanoparticle radiation sensitization on nanoparticles shows that these nanoparticles increase the radiological sensitivity of cancerous and healthy cells, while the amount of this sensitivity in cancer cells is more than healthy cells. Another finding is that hydroxyapatite nanoparticles cause apoptosis in cells. Conclusion: The present study shows the potential of hydroxyapatite nanoparticles as a radiation sensitizing agent in the treatment of breast cancer. Further studies are needed to suggest these nanoparticles as a therapeutic agent.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
113
113
https://ijmp.mums.ac.ir/article_12602_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12602
Effect of gold nanoparticles on dose enhancement of 6 Mv X-rayin MAGIC_f polymer gel dosimeter
Fatemeh Sadat
Ghoreshi
Medical Physics Department, School of Medicine, Iran University of Medical Science (IUMS), Thran, Iran
author
Jaber
Beik
Medical Physics Department, School of Medicine, Iran University of Medical Science (IUMS), Thran, Iran
author
Issac
Shiri
Medical Physics Department, School of Medicine, Iran University of Medical Science (IUMS), Thran, Iran
author
Keikhosro
Keshavarzi
Medical Physics Department, School of Medicine, Iran University of Medical Science (IUMS), Thran, Iran
author
Seyed Rabee Mahdi
Mahdavi
Medical Physics Department, School of Medicine, Iran University of Medical Science (IUMS), Thran, Iran
author
text
article
2018
eng
Introduction: Currently, the potential application of gold nanoparticles (AuNPs) to increase the efficiency of radiation therapy have been investigated. However, the loss of an appropriate method to estimate the dose distribution in nanoparticle laden tissue limits the applicability of nanoparticles in radiotherapy clinics. Polymer gel dosimetry provides an accurate and precise system that enables to measure the dose distribution in full three dimension. In this study, the radiation dose enhancement effect of AuNPs was assessed through gel dosimetry analysis.
Materials and Methods: To achieve the mentioned goal, AuNPs were impegrated in MAGIC_f polymer gel dosimeter and irradiated by 6Mv X-ray beam. Irradiated gel was then evaluated by two modalities of Magnetic Resonance Imaging (MRI) and Optical Computed Tomography (OCT).
Results: MRI and OCT scanning of the MAGIC_f geles containing 0.1 mM AuNPs demonstrated dose enhancements of 7.8% and 6.8%, respectively.
Conclusion: Polymer gel dosimetry has the potential to provide a new platform for investigation and optimization of the applicability of nanoparticles in radiation therapy
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
114
114
https://ijmp.mums.ac.ir/article_12603_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12603
Assessment of compliance levels of effective doses in pediatric CT
Dheyauldeen
Shabeeb
PhD, Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (International Campus), Tehran, Iran.
author
Ahmed
Eleojo Musa
MSc, Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (International Campus), Tehran, Iran.
author
text
article
2018
eng
Introduction: Computed tomography (CT) is a medical imaging modality that produces 3-D cross-sectional images of tissues using several X-ray projections at different angles. Since its introduction in the 1970s, CT usage has been on the increase for both adults and pediatrics. A major challenge of this modality is the high doses of radiation exposure to patients, especially in pediatrics, who are more radiosensitive compared to adults. Hence, the need to ensure that radiation safety standards are adhered to. This will go a long way in reducing the adverse effects of radiation. The aim of this study was to assess the level of compliance to international dose reference levels (DRLs) in terms of effective doses in pediatric CT scans conducted in three Iraqi hospitals.
Materials and Methods:
CT brain and abdomen/pelvis examinations were conducted for pediatric patients aged between few months and 15 years in three Iraqi hospitals (Al Wasiti, Neuroscience and Al Omara). All scans were performed on a Somatom Sensation® 16 multidetector CT (MDCT) scanner with a Straton® X-ray tube (Siemens, Erlangen, Germany) utilising automatic tube current modulation (CARE Dose4DTM; Siemens, Erlangen, Germany). Volumetric CT dose index (CTDIvol) and dose length product (DLP) were collected for 180 patients (60 in each hospital). Afterwards, their effective doses were estimated from DLP values and compared with international DRLs.
Results: Brain CT: The DLP values obtained for Al Wasiti, Neuroscience and Al Omara hospitals were in the range; 789-918.8 mGy.cm, 833-874.6 mGy.cm and 627.6-810 mGy.cm respectively, while their corresponding effective doses were in the range; 1.8-2.09 mSv, 1.9-
2.06 mSv and 1.43-1.83 mSv.
Abdomen/Pelvis: The DLP values obtained for Al Wasiti, Neuroscience and Al Omara hospitals were in the range; 392.9-425.8 mGy.cm, 355-395 mGy.cm and 314.8-383.6 mGy.cm respectively, while their corresponding effective doses were in the range; 6.65-7.22 mSv, 6-
6.7 mSv and 5.34-6.51 mSv. Using the International Commission on Radiological Protection (ICRP) publication 103 as basis for assessing compliance level, for brain CT we observe slightly higher values in Al Wasiti and Neuroscience hospitals while Al Omara was similar to the international DRLs. However, for abdomen/pelvis CT examinations, the effective doses in all three hospitals were within the acceptable limits of international DRLs.
Conclusion: This study has shown an encouraging level of compliance towards adequate radiation protection management in pediatric CT examinations among the three hospitals. Although, the best compliance level was observed in Al Omara hospital. Regular monitoring should be enforced to ensure that CT doses delivered to pediatric patients are as low as reasonably achievable without compromising diagnostic quality.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
115
115
https://ijmp.mums.ac.ir/article_12604_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12604
Iron-gold (Fe2O3@Au) core-shell nano-theranostic for magnetically targeted photothermal therapy under magnetic resonance imaging guidance
Ziaeddin
Abed
Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
Jaber
Beik
Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
Ali
Shakeri-Zadeh
Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
text
article
2018
eng
Introduction: Photothermal therapy (PTT) is a nanotechnology-assisted cancer hyperthermia approach in which the interaction between laser light and plasmonic nanoparticles generates a localized heating for thermoablation of the tumor. Recent efforts in the area of PTT follow two important aims: (i) exploitation of targeting strategies for preferential accumulation of plasmonic nanoparticles within the tumor and (ii) enabling real-time guidance of PTT operation through employing multimodal imaging modalities.
Materials and Methods: In the present study, we utilized a multifunctional theranostic nanoplatform constructed from a magnetic core and Au shell (Fe2O3@Au) in order to fulfill these aims. The Au shell exhibits surface plasmon resonance, a property that is exploited to realize PTT. The magnetic core enables Fe2O3@Au to be used as magnetic resonance imaging (MRI) contrast agent. Furthermore, the magnetic core can also be used to achieve a magnetic drug targeting strategy through which Fe2O3@Au would be concentrated in the tumor site by means of magnetic field. Balb/c mice bearing CT26 colorectal tumor model were intraperitoneally injected with Fe2O3@Au. Immediately after injection, a magnet (magnetic field strength of
0.4 Tesla) was placed on the tumor site for 6 hours in order to concentrate Fe2O3@Au, and thereafter the tumors were irradiated with the near infrared (NIR) laser source (808 nm; 2 W/cm2; 3 min). This experiment was conducted for three sessions.
Results: MRI confirmed the accumulation of nanoparticles within the tumor due to T2 enhancement capability of Fe2O3@Au. The temperature of the tumors without magnetic targeting was increased by ~7°C after NIR irradiation, whereas the tumors in magnetic targeting group showed a temperature rise of ~12°C.
Conclusion: The in vivo antitumor assessment revealed that intraperitoneal injection of Fe2O3@Au nanoparticles and their targeting via magnetic field toward the tumor followed by NIR irradiation remarkably inhibited tumor growth and induced extensive necrosis. Therefore, Fe2O3@Au can establish a targeted MRI-guided PTT strategy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
116
116
https://ijmp.mums.ac.ir/article_12605_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12605
Laser safety importance in clinical laser applications
Afshan
Shirkavand
PhD candidate of Biophotonics, Laser and plasma institute, Shahid Beheshti University- Medical laser research center, ACECR
author
Leila
Ataie Fashtami
Assistant professor of dermatology, Cell therapy clinics, Royan institute- - Medical laser research center, ACECR
author
Ezeddin
Mohajerani
Professor of Photonics, Laser and plasma institute, Shahid Beheshti University
author
Nasrin
Zand
Assistant professor of dermatology, Medical laser research center, ACECR
author
text
article
2018
eng
Introduction: By introducing of laser systems and their continuous development, a new chapter of laser systems applications in a variety fields including research and clinical science in addition to the therapeutic, diagnostic applications were available for medical professionals in various fields. Most lasers emit radiation with intrinsic probable risks where in laser-tissue interactions based on special mechanisms most important ones including photothermal, photochemical, photoablative and photomechanical, may causes potential risks and damage, similar to other side effects of thermal, chemical and mechanical in biological targets.
Materials and Methods Each of these damage mechanisms are based on multitude laser irradiation parameters including wavelength pulse duration, irradiation time, power and energy density.
Results Based on the optimized selection of the irradiation parameters and the type of the biological tissue, preliminary side effects in skin and eye organs can be prevented
Conclusion Then, it is crucial to notify laser safety considerations especially in clinical applications for both patients and operators for preventing or reducing the possible damages
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
117
117
https://ijmp.mums.ac.ir/article_12606_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12606
stimate bowtie filter shape in PET/CT scan with TLD
Nematollah
Ahmadi
PhD candidate, Department of Nuclear Engineering, Faculty of Advanced Sciences & Technologies, University of Isfahan, Isfahan, Iran
author
Alireza
Karimian
Associate Professor, Department of Biomedical Engineering, University of Isfahan, Isfahan, Iran
author
Mehdi
Nasri Nasrabadi
Department of Nuclear Engineering, Faculty of Advanced Sciences & Technologies, University of Isfahan, HezarJerib Street, 8174673441, Isfahan, Iran
author
Arman
Rahmim
Associate Professor, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
author
text
article
2018
eng
Introduction: The CT machine utilizes a bowtie filter to shape the X-ray beam and remove lower energy photons. Configuration of this bowtie filter is complex and its geometry is often not available in detail. It causes the CT dose index (CTDI) be with the different values in measurement versus Monte Carlo simulation studies and other analytical calculations. It is important especially in dosimetry of internal organs. In this study, the bowtie filter shape is extracted by using Thermolumenecence dosimeters (TLDs).
Materials and Methods: In this work, the shape of the bowtie filter of the Biograph 6 PET/CT was derived by using 31 Thermolumenecence chips dosimeters (GR-200 series) made of LiF: Mg, Cu, and P were utilized. These chips calibrated by Cs-137 in SSDL organization and ECC (Element Correction Coefficient) of them by using TLD reader Harshaw-4000. Eventually, to evaluate the accuracy of the body bowtie filter shape as generated by TLDs, Monte Carlo simulation of CT was performed. 16 X-ray sources in various angles were used within the Monte Carlo code (MCNP-4C) to simulate the CT section of the PET-CT Biograph 6 system and to calculate dose. In the simulation code, absorbed dose was determined for CT scan with MeV/gram/source particle units and converted into absorbed dose with mGy/100 mAs units by conversion factor (CF).
Results: The relative difference (RD) between simulated and measured CTDI value for the PET/CT Siemens Biograph 6 at 80, 110 and 130kVp were 4.2, 2.9 and 2.3%, respectively.
Conclusion: The results showed that it is possible to determine the shape of the bowtie filter in PET/CT using an inexpensive TLDs with acceptable accuracy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
118
118
https://ijmp.mums.ac.ir/article_12607_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12607
Enhancing and verification of dose in external radiation therapy using Gd nanoparticles as a theranostic agent: A Monte Carlo simulation study
E’tesam
Malekzadeh
University of Tarbiat Modares, Faculty of Medical Sciences, Department of Medical Physics
author
Hossain
Rajabi
University of Tarbiat Modares, Faculty of Medical Sciences, Department of Medical Physics
author
text
article
2018
eng
Introduction: Theranostics, in particular, the use of radionuclides with the capability of simultaneous imaging and treatment has opened new horizons in personalized treatment planning of targeted radiation therapy. In this approach, positive beta or gamma emitters are required for imaging and alpha, beta and Auger electrons for treatment purpose. On the other hand, studies have shown that due to high biological effectiveness the combination of external radiation modalities such as neutrons and protons with internal radiation modalities, can have a potential impact on cancer cell killing. Therefore, given the advances made in nanoparticles and radiopharmaceuticals, the necessity of designing combined therapy modalities and radiopharmaceuticals with a diagnostic-therapeutic capability is of particular importance, and Monte Carlo computational methods are a powerful tool in this regard.
Materials and Methods: In this study, by using the Geant4 and MCNPX Monte Carlo Codes, the absorbed dose of the Auger electrons, KERMA and the flux of the prompt gamma photons was calculated. the distribution of gadolinium nanoparticles with different concentrations and also without them, in two geometries of uniform PMMA environments surrounded by water and the cell model, was subjected to neutron irradiation and the dose was measured in macroscopic and microscopic conditions. Regarding the higher energy range compared to the diagnostic items in nuclear medicine, a gamma camera was optimized for counting the prompt gamma photons by using the F4 and F2 flux calculations as well as count calculation F1 MCNP tallies
Results: Dose enhancement was observed in micro and macro dosimetry conditions. For example, the amount of dose in the cellular model assigned to the nucleus was 5.1 E-5 Gy, 3.01E-03 Gy, and 4.05E-7 Gy for the distribution of Gd in the core, total nucleus, and cytoplasm for particle history, respectively. There was also a direct correlation between the number of prompt gamma rays and the nanoparticle concentration
Conclusion: Labeling of antibodies or peptides with gadolinium nanoparticles in the presence of external radiation beam can be used as a marker for drug distribution, as well as targeted radiation therapy theranostic agent because of enhancement of doses due to auger electrons and prompt gamma photons with imaging capability that showing the synergy impact of diagnostic imaging and therapeutics.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
119
119
https://ijmp.mums.ac.ir/article_12608_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12608
Analysis of the theory of thermal damage in biological tissues caused by Laser beam
Aryabod
Elham
Department of Physics, Payame Noor University, Tehran, Iran
author
text
article
2018
eng
Introduction: In laser surgery, the laser beam can evaporate and cut the tissue like a small surgical knife when the tissue temperature is heated to 100 degrees Celsius. a complete understanding of the distribution of damage in both pathologic tissue and surrounding tissue is necessary. Although the test is the most realistic solution for treating medical problems, for this reason, theoretical investigation of thermal damage in laser tissue is used as an alternative method.
Materials and Methods: The diffusion of laser light in the tissue is initially solved using a robust seven-fluid model in the cylindrical coordinate system. The spatial distribution of the absorbed laser energy is introduced into the environmental transfer equation to solve the temperature response. Heat damage to tissues is determined according to the amount of dental protein by using the equation of the rate process.
Results: Heat damage to tissues is determined according to the amount of dental protein by using the equation of the rate process. It has been found that significant protein denaturation can occur when the temperature is over 53 ° C.
Conclusion: When a tissue radiates with a continuous laser beam with constant power in time, the damage parameter is also stored even after the laser is shut down. The most serious tissue damage occurs after laser radiation, when the temperature is about 53 ° C.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
120
120
https://ijmp.mums.ac.ir/article_12609_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12609
Photon Dosimetry Quality Audit of Radiotherapy Centers in Iran: SSDL's On-Site Visit Program During 2007-2017
Kourosh
Arbabi
MSc in Medical Physics, Dosimetry and Radiation Monitoring Group, Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI), Karaj, Iran.
author
Ali
Rajabi
MSc in Medical Radiation Engineering, Therapy Level Laboratory, Secondary Standard Dosimetry Laboratory (SSDL), Pars Isotope Co., Karaj, Iran.
author
Mahmoudreza
Akbari
MSc in Medical Radiation Engineering, Therapy Level Laboratory, Secondary Standard Dosimetry Laboratory (SSDL), Pars Isotope Co., Karaj, Iran.
author
text
article
2018
eng
Introduction: A dosimetric audit is a quality assurance process (QA) that allows the accuracy of dosimetric and geometric precision to accurately control the delivery of doses. They can be used to evaluate the accuracy of radiation delivery at different radiotherapy centers. Differences in prescriptive doses, depending on the severity of the differences, have potential consequences not so important, severe and even fatal. Measuring the absolute output of linear accelerators (LINACs) under reference conditions is a standard method for verifying the accuracy of dose delivery. In this study, Radiotherapy centers in Iran were audited by the secondary standard dosimetry laboratory (SSDL). The absolute photon output of the accelerators and some of the relative factors such as wedge factor, shield tray factor, total scatter factor was measured using a Farmer chamber and the results were compared with the reported values by the radiotherapy physicist of centers. The differences between SSDL and the inspected center were reported.
Materials and Methods: Measurements were performed at 178 on-site visits from 61 radiotherapy centers (including 98 LINACs) between March 2007 and October 2017. Some participating centers were visited more than once. Photon absolute dose measurements were carried out according to TRS-398 protocol using Farmer ionization chamber (TW30013). Action levels were determined including ±3% for absolute dose and ±2% for relative factors.
Results: Absolute dose differences between SSDL and local centers were in the range of -3.5% up to 4%. The differences in the values of the wedge factor between the amounts measured by SSDL and the local centers were -3.5% up to 3.36%. The minimum and maximum differences in the total scatter factor were -3.4% up to 3.7%. The differences in the obtained tray factor values were -1.4% up to 2.5%. The difference between SSDL and radiotherapy centers at the reported absolute dose values in 11 beam measurements was greater than the permissible limits. Moreover, 299 beam measurements were within the tolerance.
Conclusion:
Differences in measurements between SSDL and radiotherapy centers could be due to the following: I. Lack of qualified medical physicists in some radiotherapy centers, II. Error in calculating beam quality factor (kQ) for some chambers, III. Mistake in the report of the reference depth and reference source to surface distance (SSD).
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
121
121
https://ijmp.mums.ac.ir/article_12610_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12610
Cytotoxicity of 5-ALA-conjugated bismuth oxidenanoparticles on KB cell line
Fatemeh
Akbarzadeh
M.Sc Student of Medical Physics, Students Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Karim
Khoshgard
Assistant Professor, Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Leila
Hosseinzadeh
Pharmaceutical Sciences Research Center, School of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Elham
Arkan
Nano Drug Delivery Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: In recent years, bismuth-based nanomaterials have been widely used in medical researches as imaging, drug delivery and x-ray radiosensitizing agents. Due to their anti-microbial effects against Helicobacter pylori (HP), bismuth colloidal compounds are used to treat various types of diseases such as chronic gastritis. Despite their advantages, bismuth-based compounds have shown many toxic effects in humans. There are few studies on cytotoxicity effects of bismuth (ΙΙΙ) oxide (Bi2O3) nanoparticles (NPs). Based on the natural high affinity of folate for the folate receptor protein (FR), which is commonly expressed on the surface of many human cancers, folate-drug conjugates bind tightly to the FR and trigger cellular uptake via endocytosis. Therefore, we aimed to investigate the cytotoxicity effects of 5-ALA-conjugated Bi2O3 NPs, 5-ALA-folate-conjugated Bi2O3 NPs and free 5-ALA on oral squamous carcinoma cell line (KB cells) for the first time. 5-ALA is used in photo dynamic detection and photodynamic surgery of cancer. Being a precursor of a photosensitizer, 5-ALA is also used as an add on agent for photodynamic therapy. Materials and Methods: Bi2O3 NPs were synthesized and conjugated with folate and 5- aminolevulinic acid (5-ALA). KB cells were cultured monolayer and incubated with 10, 20, 50, 100 and 200 μg/ml concentrations of free 5-ALA, 5-ALA-folate-conjugated Bi2O3 NPs and 5-ALA-conjugated Bi2O3 NPs for 24 hours. The survival of the cells obtained after 24 h of incubation with the materials using MTT assay. Results: Bi2O3 NPs were synthesized (~20 nm) and conjugated to folate and (5-ALA). Results indicated that the significant cellular death were noted at the concentrations more than of 50 μg/ml for all compounds that cell viability reduced to 37%, 49% and 63% in groups receiving 5-ALA-folate-conjugated NPs, 5-ALA-conjugated Bi2O3 NPs and free 5-ALA, respectively. The cytotoxicity of the materials on KB cells also increased with increasing concentrations of synthesized NPs. Conclusion:5-ALA-folate-conjugated NPs, 5-ALA-conjugated Bi2O3 NPs and free 5-ALA were easily taken up by the cells and showed cytotoxic effects at high concentrations. Folic acid conjugation facilitates selective targeting of the KB cells with the overexpression of the folate receptors and improves internalization of the drugs through receptor-mediated endocytosis
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
122
122
https://ijmp.mums.ac.ir/article_12611_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12611
A New Method for Estimating of Patient Effective Dose in Computed Tomography Based on Body Mass Index: Performance of the Method in Abdomen-Pelvic Examination
Mohammad Hossein
Jamshidi
Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammad Reza
Deevband
Department of Medical Physics and Biomedical engineering, Shahid-Beheshti University of Medical Sciences, Iran
author
Mohammad Javad
Tahmasebi Birgani
Department of Radiation Therapy, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Iran
Department of Radiology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Iran
author
Ali
Yadollahpour
Department of Radiation Therapy, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Iran
author
Morteza
Tahmasebi
.
author
text
article
2018
eng
Introduction: The CT Provide high quality images, especially in low-contrast soft tissue, are another advantage. Along with all the benefits that the CT scans which have, the patient dose of this modality is much greater than other methods. As a result, medical imaging community must ensure that the benefits of radiological examination for each patient are higher than related risks. Although the CT has a small percentage of radiological examination, but it has a large contribution on the exposure to the community. the purpose of the present study was to investigate how the introduction of MDCT scanners and patient-size-dependent imaging protocols have affected patient doses and propose a simple method to predict an estimation of the organ and effective doses by using BMI and mAeff. The nobility of the present scientific study was to investigate how the introduction of MDCT scanners and patient-size-dependent imaging protocols have affected patient doses.
Materials and Methods: Demographic data of each patient were recorded as well as data from a CT scan of the abdomen and pelvic of 52 patients were studied. For assessment of patient and effective doses, the information related to the scan in ImPACT software was applied. The results are analyzed and regression was used in order to examine the relation between the results of the scan data in MATLAB environment.
Results: The research findings showed that the received dose to the most patients is the same as determined by the ICRP103. An average of the effective dose(6mSv) was less than predicted amount by ICRP103. To estimate the effective dose of the body, according to the patient’s BMI, an equation was obtained [Effective Dose (mSv) = 0.257 BMI - 0.637]. The results from this equation are corresponded to the calculated dose by Impact (R2>0.95). In addition, the method was proposed to predict the parameters of mAeff and DLP resulted from the related scan. [mAeff (mGy.cm) = 4.73 BMI -19.81 , DLP(mGy.cm) = 17.17 BMI -56.36].
Conclusion: According to the results of this study, authors proposed a good alternative to estimate the effective dose according to BMI instead of ImPACT calculations for scanners and scanning conditions as well as a method to predict the effective dose by using the parameters of the CT system and BMI without being radiated on the patients.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
123
123
https://ijmp.mums.ac.ir/article_12617_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12617
Quantum mechanical proton range in human body
Aryabod
Elham
Department of Physics, Payame Noor University, Tehran, Iran,
author
text
article
2018
eng
Introduction: Proton therapy delivers radiation to tumor tissue in a much more confined way than conventional photon therapy thus allowing the radiation oncologist to use a greater dose while still minimizing side.
Materials and Methods: protons release most of their energy within the tumor region. As a result, the treating physician can potentially give an even greater dose to the tumor while minimizing unwanted side effects. This is especially important when treating children, because protons help reduce radiation to growing and developing tissues. In this work by Bethe formula using quantum mechanics we determine stooping power, mass stopping power and range of proton in substances of human body and compared our obtained results with available experimental data.
Results: We calculated mean excitation energies, I using the quantum mechanical approach in muscle, bone, water, tissue. Our obtained results show that this parameter will change from 19 to 1000 eV. After that by Bethe formula using quantum mechanics with determining stooping power, mass stopping power and range of proton in ovary, breast, eye lens, lung, adipose, brain blood, bone, muscle and water we find that both of stopping and mass stopping power at first increases with enhancement of proton energy then decreases while, range of protons increases with increasing of proton energy.
Conclusion: In this research, by Bethe formula using quantum mechanics the numerical values of stopping, mass stopping power and proton range in substances of human body are determined accurately and these obtained results help more accurately treat cancer patients using proton therapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
124
124
https://ijmp.mums.ac.ir/article_12618_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12618
Dosimetric and Radiobiological Evaluation of Multiparametric MRI-guided Dose Painting in radiotherapy of Prostate Cancer
Iraj
Abedi
Faculty Member of Medical Physics, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Mohammad Bagher
Tavakkoli
Professor of Medical Physics Faculty, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Keyvan
Jabbari
Associate Professor of Medical Physics Faculty, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Alireza
Amouheidari
Radiation oncologist, Isfahan Milad Hospital, Isfahan, Iran.
author
Ghasem
Yadegar-far
Associate Professor of Health Faculty, Isfahan University of Medical Sciences, Isfahan, Iran.
author
text
article
2018
eng
Introduction: Radiotherapy is one of the treatment options for locally advanced prostate cancer, however with standard radiation doses it is not always very effective. One of the strategies to improve the efficiency of radiotherapy is increasing the dose. In this study to increase tumor local control rates a new radiotherapy method, known as dose painting (DP) was investigated.
Materials and Methods: Twenty-four consecutive patients with locally advanced prostate cancer who underwent an MP-MRI (T2w, DWI, DCE, MRS) scan, before a diagnostic biopsy from September 2015 to April 2016 were invited to take part in this study.
Results: The TCP values for 3D-CRT, IMRT and DP techniques were 45%, 56% and 77%, respectively. The DP technique had a 37.5% and 71% higher TCP than IMRT and 3D-CRT, and these differences were statistically significant (P = 0.001).
The mean NTCP values of the OARs for 3D-CRT, IMRT, and DP showed that there were statistically significant differences between them in three plans (p = 0.01).
Conclusion: Dose painting by contours using MP-MRI is technically feasible. This study evaluated biological modeling based on both MP-MRI defined sub-volumes and pathologically defined sub-volumes. The MP-MRI guided dose painting results in the better TCP/ NTCP than 3D-CRT and IMRT.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
125
125
https://ijmp.mums.ac.ir/article_12619_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12619
Magnetic hyperthermia and MRI relaxometry with dendrimer coated iron oxide nanoparticles
Marzieh
Salimi
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
Research Center of Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
Saeed
Sarkar
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
Research Center of Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
Samaneh
Fathi
Department of Medical Nanotechnology, Tehran University of Medical Sciences, Tehran, Iran
author
Reza
Saber
Research Center of Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Recently, some studies have focused on dendrimer nanopolymers as an MRI contrast agent or a vehicle for gene and drug delivery. Considering the suitable properties of these materials, they are appropriate candidates for coating iron oxide nanoparticles which are applied to magnetic hyperthermia. To the best of our knowledge, the novelty of this study is the investigation of fourth-generation dendrimer-coated iron oxide nanoparticles (G4@IONPs) in magnetic hyperthermia and MR imaging.
Materials and Methods: IONPs were synthesized via co-precipitation and coated with the fourth generation (G4) of poly amidoamine (PAMAM) dendrimer. The cytotoxicity of G4@IONPs with different concentrations was assessed in hum a breast cancer cell line (MCF7) and human fibroblast cell line (HDF1). Hemolysis and stability of G4@IONPs were investigated and also, the interaction of these particles with MCF7 cells was assessed by Prussian blue staining. Heat generation and specific absorption rate (SAR) were calculated from measurement and simulation results at 200 and 300 kHz. MCF7 and HDF1 cells were incubated with G4@IONPs for 2 h and then put into the magnetic coil for 120 min. relaxometry experiments were performed with different concentrations of G4@IONPs with T1 and T2-weighted MR images.
Results: The TEM results showed that G4@IONPs were 10±4 nm. The in vitro toxicity assessments showed that synthesized NPs had low toxicity. The viability of MCF7 cells incubated with G4@IONPs decreased significantly after magnetic. Also, MR imaging revealed that G4@IONPs improved transverse relaxivity (r2) significantly.
Conclusion: Our results encouraged the future application of G4@IONPs in magnetic hyperthermia and MR imaging.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
126
126
https://ijmp.mums.ac.ir/article_12620_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12620
Effect of magnetic fluid hyperthermia with dendrimer coated iron oxide nanoparticles on breast cancer in BALB/c mice
Marzieh
Salimi
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
Research Center of Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
Saeed
Sarkar
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
Research Center of Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
Reza
Saber
Department of Medical Nanotechnology, Tehran University of Medical Sciences, Tehran, Iran
Research Center of Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Magnetic fluid hyperthermia (MFH) is a promising therapeutic method in cancer therapy with using magnetic nanoparticles (NPs). In this study, we assessed the effect of MFH on mechanisms of cell death in murine breast cancer cell line (MC4-L2) and also the treatment of breast tumor in BALB/C mice using four generation dendrimer coated iron oxide nanoparticles (G4@IONPs).
Materials and Methods: Immediately after MFH, the viability of cells was assessed in all groups (MFH+NPs, only MFH, only NPs, control) by MTT assay. In order to determine the number of apoptosis and mRNA copies for Bax and Bcl-2 in the cells after MFH, TUNEL assay and RT-PCR were performed, respectively. The mice were exposed three times during twenty minutes to an MFH (12 kA/m, 300 kHz) after intertumoral injection of 5mg G4@IONPs. The temperature during MFH was monitored with an infrared thermometer (FLIR Systems). Tumor volume was measured during 28 days after MFH. Histopathology, Immunohistochemical staining, and TUNEL assay were performed in the liver and tumor tissues.
Results: Cell viability percentage in the group of MFH+NPs decreased significantly (33%, P<0.05) while the viability in other groups had no any significant change. Also, the number of apoptotic cells and Bax/Bcl-2 ratio in MFH+NPs increased significantly. The MFH led to significantly reduce the volume of the tumor 30 days after the treatment compared with control mice (saline injection) (p < 0.05). tissue destruction obviously was seen in tumor histopathology of MFH+NPs mice. CD31 as angiogenesis marker decreased in treated tumors compared with control ones and furthermore, apoptosis significantly increased in treated tumor tissues.
Conclusion: Our study showed MFH with G4@IONPs could demolish the cancer cells mainly because of increasing the apoptosis and regulating the apoptotic genomes including Bax and Bcl-2. MFH can applied as a clinical anti-cancer strategy due to inhibition of tumor angiogenesis.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
127
127
https://ijmp.mums.ac.ir/article_12621_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12621
Effect of dispersion state of the magnetic Fe3O4 nanoparticles on the thermal distribution in Hyperthermia
Ali
Rajabi
Secondary Standard Dosimetry Laboratory (SSDL), Pars isotope Co., Karaj, Iran.
author
Shahryar
Malekie
Radiation Application Research School, Nuclear Science & Technology Research Institute, Karaj, Iran.
author
text
article
2018
eng
Introduction: Magnetic nanoparticle (MNP) hyperthermia is a promising cancer treatment approach. It is based on the evidence that by injecting MNPs such as Fe3O4 in the tumor and subjecting them to an alternating magnetic field, they release heat, generating temperatures up to 42°C that can kill cancer cells by apoptosis, usually with lowest damage to normal tissue. In previous work the temperature distribution of an ordinary tumor over the different sizes of Fe3O4 MNPs with uniform dispersion in tumor was performed.
The objective of this work is to evaluate the thermal distribution of MNPs in the tumor tissue using random and array geometries due to dispersion states of the inclusions.
Materials and Methods: The bio heat transfer equation (BHTE) formulated by Pennes, describes thermal processes in the human body. Since finding the exact solution of BHTE for a complex system like tumor tissue is a challenging issue, so finite element method in the COMSOL Multiphysics software is used to capture more details in predicting the temperature distribution in tumor tissue during the hyperthermia therapy. Producing the random and array numbers for distribution of the MNPs into the tumor tissue was carried out with MATLAB software. Fe3O4 MNPs with the size of 100 nm with different distributions in the tumor were simulated and the temperature distribution of the tumor and normal tissue was calculated, taking into account the thermal conductivity, density, and heat capacity.
Results: The distribution of temperature in the tumor depends on Fe3O4 MNPs distribution. Uniform distribution of MNPs has appropriate distribution in the tumor and normal tissue around it. And also the agglomeration of MNPs in the tumor tissue leads to non-uniformity of the temperature distribution of the inclusions.
Conclusion: In this research, the temperature distribution of an ordinary tumor over the different distributions (random and array) of Fe3O4 MNPs was investigated via the finite element method. The bio heat transfer equation was used to calculate the thermal processes in the tumor and normal tissues around it. It should be taken into account the distribution states of the MNPs into the tumor tissue and its subsequently effects on the thermal distribution. Finally, results showed that uniform distribution of the magnetic nanoparticles into the tumor tissue exhibited more appropriated results.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
128
128
https://ijmp.mums.ac.ir/article_12622_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12622
Assessment of environmental high-doses using Raman spectroscopy of gamma irradiated MWCNT-OH Nanopowder utilized in radiation accidents
Ahmad Reza
Vatankhah
Department of Nuclear Engineering, Islamic Azad University Arsanjan Branch, Arsanjan, Iran
author
Mohammad Amin
Hosseini
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
author
Shahryar
Malekie
Radiation Application Research School, Nuclear Science & Technology Research Institute, Karaj, Iran
author
text
article
2018
eng
Introduction: The functionalized Multi-Walled Carbon Nanotube with hydroxyl group (MWCNT-OH) due to high aspect ratios (length to diameter), and also excellent mechanical, electrical and thermal characteristics, has great potential applications in flexible electronics, solar cells, antistatic devices, electromagnetic interference shielding, radiation shielding, electrode materials for batteries, lightweight energy storage devices, supercapacitors, piezoelectric sensors, radiation sensors, and dosimeters. Several experiments showed that gamma irradiation can be used to modify the mechanical, and electronic properties of nanostructured carbon materials via the creation of atomic defects in the materials. Raman spectroscopy is a powerful tool for the characterization of carbon nanostructures. According to Raman spectroscopy of nanostructured carbon materials, there are two main peaks of D- band and G-band at 1344 cm-1, 1574 cm-1 respectively. Also there is another peak entitled G' that is indicator of second mode of vibrations in the carbon atoms near 2680 cm-1. The ratio of ID/IG is a characterizing agent for determination of structural defects created in carbon nanostructures. It is expected to increase the amount of ID/IG after gamma irradiation of MWCNT-OH sample at high dose irradiations. Regarding this fact, if the plot of ID/IG versus absorbed dose would be linear, so it can be deduced that this material can be used as a dosimeter.
Materials and Methods: In this experimental work, MWCNT-OH Nanopowder with density of 2.1 g/cm3, the outer diameter of 5-15 nm, the inner diameter of 3-5 nm, 50 μm length, the electrical conductivity between 105-107 S/m, containing 1.7 wt% –OH groups was prepared from US Nano Inc and irradiated by gamma rays of 60Co gamma-cell installed in Atomic Energy Organization of Iran-Tehran with dose rate of 1.62 Gy/s within the different doses of 0-30 kGy at room temperature. Raman spectroscopy model Takram P50C0R10 with 532 nm Nd:YAG laser in the range of 100–4600 was applied.
Results: According to Raman spectroscopy of the samples, the ratio of ID/IG versus absorbed dose exhibited a linear response in the range of 0-20 kGy and after that saturation effect was dominant. The maximum increase in the ID/IG value in comparison with pristine sample was
±18.7 % at 20 kGy.
Conclusion: In this experimental work, MWCNT-OH Nanopowder was prepared and irradiated by gamma rays in different doses of 0-30 kGy at room temperature. The samples were subjected to Raman spectroscopy to determine the defects created in the carbon atoms of the nanostructure materials. Results showed that the amount of ID/IG versus absorbed dose exhibited a linear behavior in the range of 0-20 kGy that can be used for high dose level dosimetry purposes especially assessment of dose in the radiation accidents at nuclear facilities.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
129
129
https://ijmp.mums.ac.ir/article_12623_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12623
Evaluation of X-Ray Absorption by Ointment Containing Bismuth Oxide Nanoparticles in Radiology Staff
Mohsen
Shoja
Depatment of Radiology, Faculty of Paramedicine, Semnan University of Medical Sciences, Semnan, Iran. Tel: 00982333654162 Email: Moh3n_sh_66@semums.ac.ir
author
Kamran
Vahidizade
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
author
Mohadese
Soleimani
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
author
text
article
2018
eng
Introduction: The effects of X-rays on carcinogens have been proven in recent years. Today, lead is used in many devices such as lead covers, thyroid protectors to protect the body against x-rays. But this equipment contains many disadvantages such as, Toxicity, High weight and Lack of flexibility. Today, newer methods, such as semi-solid skin care products (cream, ointment), are used. In this study, the feasibility of using a cream containing bismuth oxide nanoparticles as an X-ray absorbent was studied.
Materials and Methods: Bismuth oxide nanoparticles structure (Bi2O3) and formulation in ointment form was surveyed. Then were formulated by a new method using sorbitol synthesis. The final cream consists of 70% bismuth oxide nanoparticles and 30% other ingredients. Then the absorption of x-rays in different thicknesses of ointment was evaluated.
Results: A dosimetry test showed that the protective effect of ointment was significantly (P<0.05) better than the lead Sheet as control group. Dosimetry tests showed that the ointment of bismuth oxide nanoparticles absorbed 56% of the radiation, but the lead just absorbed 41%. Bismuth K absorption edge is more than other metals and its nanoparticles have higher absorption surface to volume (S/V).
Conclusion: Bismuth oxide nanoparticles, due to the high atomic number of bismuth, is more efficient than lead in X-ray absorption, and is less toxic. Bismuth oxide nanoparticles cream can be used as X-ray absorbent for various occupations such as doctors, dentists, operating room staff and radiologists, and increases the health and safety of the staff.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
130
130
https://ijmp.mums.ac.ir/article_12624_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12624
Evaluation of radiation protection principles and 10-day rule observance for women prone to pregnancy at imaging centers of S emnan University of medical sciences
Mohsen
Shoja
Depatment of Radiology, Faculty of Paramedicine, Semnan University of Medical Sciences, Semnan, Iran. Tel: 00982333654162 Email: Moh3n_sh_66@semums.ac.ir
author
Niloufar
Asbaghipour
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
author
Maryam
Ameriyan
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
author
Mohadese
Soleimani
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
author
text
article
2018
eng
Introduction: Today, the spread of the use of ionizing radiation and its vital role in the diagnosis and treatment of diseases has been identified. Therefore, protecting pregnant women from ionizing radiation is essential and is considered as the standard criterion for Medical Radiation center. The aim of this study was to investigate the observance of protective principles and The law of 10 days in imaging of susceptible women in Semnan University of Medical Sciences imaging centers has examined the risk of fetal radiation and the transmission of genetic damage to future generation.
Materials and Methods: Firstly, by interviews with patients who were under radiography, they were asked about the knowledge of the Radiographers and the doctor related about the 10-day rule. Then a questionnaire was given to the Radiographers. Finally, the existence or absence of written protection guidelines was determined by direct observation. Data were analyzed by SPSS software and data were analyzed using descriptive statistics.
Results: Based on the findings of the first part the study of patients about pregnancy is not done in about 21% of cases. The mean score for the knowledge of hospital personnel was
14.47. On the other hand, there was no observance of the instructions regarding pregnant women and the law for 10 days in Amiralmomenin and Velayat and Imam Hossein hospitals.
Conclusion: Since genetic damage not thresholds dose and it is possible even at low doses, so attention to radiation in pregnant and prenatal women can lead to the risk of fetal radiation and the transmission of genetic damage to future generations to Too much to overcome. Therefore, the necessity of using the latest radiation protection methods is mandatory.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
131
131
https://ijmp.mums.ac.ir/article_12625_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12625
Development and Characterization of Synthetic Tissue- Equivalent Material for CT Imaging Applications
Sadegh
Shurche
Physics and Medical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
author
Nader
Riahi Alam
Physics and Medical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran/ Tel: +98-21- 66466383, Fax: +98-21- 88973653, E-mail: riahialam@gmail.com
author
Mohamad
Yousefi Sooteh
Medical Physics Department, Tabriz University of Medical Sciences, Tabriz, East Azerbaijan, Iran
author
text
article
2018
eng
Introduction: The use of a simple tissue analog material in the fabrication of medical computed tomography (CT) imaging phantoms has great potential to help researchers. The purpose of the present study is to develop new gel tissue-equivalent materials and determine whether their CT numbers and relative electron densities vary in CT images obtained by scans at different energies.
Materials and Methods: First, we designed a phantom using six cuvettes. We then made 36 gels using nickel-doped agarose, sucrose, urea, and sodium chloride, and six solutions using K2HPO4. Finally, we measured the CT numbers and relative electron density of each gel and solution using a Siemens SOMATOM Emotion 16 scanner.
Results: The CT numbers and relative electron density of the gels closely resembled those of real tissue. The CT number of each gel was higher than that of water. In addition, the CT numbers for all materials decreased as the X-ray energy increased from 80 to 130 kVp.
Conclusion: Our study found that the CT numbers and relative electron density of gels that include nickel- doped agarose, sucrose, urea, and sodium chloride (as soft tissue) and K2HPO4 (as bone) indicate that the gels have the potential to be used as tissue substitutes. It is feasible to create an anthropomorphic phantom using the gels developed in this study.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
132
132
https://ijmp.mums.ac.ir/article_12626_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12626
Fabrication of New 3D Phantom for Measuring Geometric Distortion in Magnetic Resonance Imaging System
Sadegh
Shurche
Physics and Medical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
author
Nader
Riahi Alam
Physics and Medical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran/ Tel: +98-21- 66466383, Fax: +98-21- 88973653, E-mail: riahialam@gmail.com
author
Mohamad
Yousefi Sooteh
Medical Physics Department, Tabriz University of Medical Sciences, Tabriz, East Azerbaijan, Iran
author
text
article
2018
eng
Introduction: Geometric distortion is a major shortcoming of magnetic resonance imaging (MRI), which has an important influence on the accuracy of volumetric measurements, an important parameter in neurology and oncology. Our goal is to design and construct a new three- dimensional phantom using a 3D printer in order to measure geometric distortion and its reproducibility in three dimensions.
Materials and Methods: In this study, we designed a new phantom containing 13,824 reference features (control points) with AutoCAD software, fabricated it with a 3D printer, and filled it with vegetable oil. This phantom was tested on the Siemens 3 Tesla Prisma MRI model using a 64-channel head coil. We used imaging from a six-slice CT scan (Siemens) as a reference and matched the reference features in the MRI images with the CT-scan images. To achieve this, we used a three-dimensional reference feature model. Reproducibility on the phantom was investigated with three different imaging sessions per day for three different days.
Results: The geometric distortion in the 3D results was found to be due to field non-uniformity and nonlinearity of the gradients and its reproducibility. The mean Euclidean distance error for MRI volume was less than 1 mm. The maximum Euclidean error was 1.5 mm. Distortion in the whole volume is pronounced exclusively at the edges of the magnetic field.
Conclusion: As with other investigations carried out in our work, the amount of distortion in the middle of the field was less than at its sides. This phantom can be used to check the distortion filters on the device. Also, this phantom can be used to study geometric distortion in scenarios that require a small study volume, such as prostate studies.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
133
133
https://ijmp.mums.ac.ir/article_12627_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12627
Magnetic Graphene Oxide Nanocarrier as a drug delivery vehicle for MRI monitored magnetic targeting of rat brain tumors
Sakine
Shirvalilou
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, IRAN.
author
Samideh
Khoei
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, IRAN. Email: khoei.s@iums.ac.ir, Tel: +98 9125468630
Razi Drug Research Centre, Iran University of Medical Sciences, Tehran, IRAN
author
Sepideh
Khoee
Department of Polymer Chemistry, School of Sciences, University of Tehran, Tehran, IRAN
author
Soraya
Emamgholizadeh Minaei
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, IRAN.
author
text
article
2018
eng
Introduction:
Glioblastoma multiform is the most common malignant brain tumor, with an invasive nature. Despite the development of conventional therapies such as surgery, radiotherapy and chemotherapy, because of high recurrence rates, the prognosis remains very poor. Over the last decade, nanotechnology has represented an innovative method as nanoparticle-based drug delivery carriers to overcome the BBB transport. Multifunctional magnetic nanoparticles are powerful tools for current clinical diagnostics, imaging and therapeutic procedures.
Materials and Methods:
Magnetic targeting studies were carried out in C6 glioma tumor-bearing Wistar rats using intravenous magnetic nanoparticles administration under permanent magnetic phantom. Animals were placed ventrally on a platform with their head positioned between two blocks of NdFeB permanent magnet (1.3 tesla). Measurements of magnetic density in the space between the two blocks were carried out using a tangential B-probe Teslameter (LEYBOLD, Germany). MNP (9 mg/kg) were injected into the tail vein of rats, seventeen days after implantation and retained in the magnetic field for 2h. To evaluate brain- targeting ability of nanoparticles, the rats were imaged with MRI before the administration of nanoparticles and after the magnetic targeting. Immediately following MRI, the animals were sacrificed and the brains were collected for Prussian blue staining.
Results:
Magnetic NGO/PLGA nanoparticles with a diameter of 71.8 nm, a zeta potential of -33.07±0.07 mV presented superior superparamagnetic properties with a saturation magnetization of 15.98 emu/g. The results of MR T2 images and Prussian blue staining of rat brains indicated MNPs could overcome the BBB for glioma targeting in the presence of a permanent magnetic field. The measured magnetic density at the GBM area was 450 mT, the value measured 2.5 cm caudal to the tumor was 325 mT, indicating that the tumor would be exposed to a maximum magnetic force. Furthermore, the MRI images demonstrated MNPs could be used in noninvasive MR imaging techniques and enhance the MRI sensitivity to offer better chemotherapy and real time monitoring.
Conclusion:
In the present study, for the first time, we combined the concepts from these two fields to synthesize magnetic NGO nanoparticles and indicated its high-level specificity to magnetic targeting C6 glioma rats, that its ability to serve as an excellent contrast enhancement agent for MRI.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
134
134
https://ijmp.mums.ac.ir/article_12628_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12628
Formulation of temozolomide by folic acid-conjugated tri-block copolymer nanoparticles for targeted drug delivery
Soraya
Emamgholizadeh Minaei
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
author
Samideh
Khoei
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. . E-mail: khoei.s@iums.ac.ir, Tel: +98 9125468630
Razi Drug Research Centre, Iran University of Medical Sciences, Tehran, Iran
author
Sepideh
Khoee
Department of Polymer Chemistry, School of Sciences, University of Tehran, Tehran, Iran
author
Sakine
shirvalilou
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Glioblastoma multiforme (GBM) is the most frequent primary malignant tumor of the brain. But, the treatment of GBM is one of the most problems in cancer therapy because of poor drug penetration across the blood-brain barrier (BBB). Targeting drug delivery system and conjugating targeting moieties was recognized to overcome the poor penetration of chemotherapy drugs into tumor cells. In the present study, folic acid- conjugated magnetite tri-block copolymer was utilized to targeted chemotherapy of the glioma cells.
Materials and Methods: The characterization and morphology of NPs (SPION-PEG-PBA- PEG, SPION-PEG-PBA-PEG-FA, TMZ-SPION-PEG-PBA-PEG, and TMZ-SPION-PEG-PBA-PEG-
FA) were determined by Dynamic Light Scattering (DLS) analysis and transmission electron microscope (TEM). The in vitro release behaviors of TMZ from NPs were evaluated with an equilibrium dialysis bag diffusion method. Additionally, to identify the targeting effect of FA- conjugated NPs, C6 glioblastoma cells and OLN-93 glial cells were used. The cytotoxicity effect of NPs was determined by the MTT assays in both cell lines.
Results: DLS analysis showed that all nanoparticles had mean diameters of 24-49 nm. In our study, TMZ entrapment efficiency of TMZ-SPION-PEG-PBA-PEG-FA and TMZ-SPION-PEG- PBA-PEG nanoparticles were 52.8 and 50%, respectively, with the drug loading capacity of
6.65 and 6.3%, respectively. It was found that nearly 90% of TMZ in stock solution was released within the first 2 h. However, TMZ-loaded NPs generated only 75% leakage within the 48 h and revealed a sustained release feature, which might be described by that drug was gradually released with the dissolution of polymers. The results from the MTT assay indicated that TMZ-SPION-PEG-PBA-PEG-FA NPs revealed the highest anti-proliferation effect on the C6 cells compared with OLN-93 cells (P < 0.0001). Also, compared with unmodified NPs, conjugation with FA-ligand could further elevate the cytotoxicity effect on C6 cells (P < 0.0001) which demonstrated a satisfactory drug delivery system.
Conclusion: TMZ-SPION-PEG-PBA-PEG-FA NPs served as a potential system for the transport of TMZ across the GBM cells through receptor-mediated endocytosis. The results revealed that proposed system could be exploited as potential carrier for delivery of drugs to the brain.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
135
135
https://ijmp.mums.ac.ir/article_12629_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12629
Evaluation of Full scatter convolution algorithm based Treatment Planning System performance in the presence of inhomogeneities using three-dimensional film dosimetry
Ahad
Zainali
Medical physics department, Faculty of medicine, Urmia Medical Acience University
author
Leila
Mahani
Department of Medical Physics, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
author
text
article
2018
eng
Introduction: Inclusion of inhomogeneities such as air-filled cavities in the head and neck treatment fields may result in potential dosimetric disagreement which was caused by electronic disequilibrium. Most of treatments planning systems (TPS) are not able to predict dose distribution of inhomogeneous regions accurately. EBT2 films are used frequently in radiotherapy quality assurance testing to evaluate the performance of dose delivery systems and TPS. The development and usage of 3D film dosimetry method may be useful.
Materials and Methods: 9 pieces of EBT2 films were embedded in a rectangular inhomogeneous head and neck phantom. Films were exposed with 6 MV X-ray photons with parallel-opposed fields and three approximate small field sizes were examined. A homemade computer code was developed in MATLAB for creation of 3D dose map of irradiated films and calculation of enclosed volumes which were surrounded by isodose lines of films. Calculated dose volumes should be compared with Dose Volume Histogram (DVH) which was derived from TPS.
Results: our results showed significant differences between the results of the film dosimetry and TPS. Maximum difference of calculated and measured values was observed in volumes surrounded by 95% isodose curves and 3x3cm2 field size (P=0.035) and minimum difference was observed in volumes surrounded by 95% isodose curves and 5x5cm2 field size (P=0.047).
Conclusion: The results of this study demonstrated overestimated results in volumetric calculation of TRGRT dose calculation algorithm in the presence of inhomogeneities and approxi small fields sizes. Also, these results confirmed that utilization of an accurate and comprehen method such as 3D film dosimetry can be useful for TPS verification.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
136
136
https://ijmp.mums.ac.ir/article_12630_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12630
Using Zirconium Borohydride as Neutron Shield in LINAC head
Mohammad
Ashrafinia
MSc student, Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran 09127210958, mohammad.ashrafinia@srbiau.ac.ir
author
Asghar
Hadadi
Assistant professor, Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Dariush
Sardari
Assistant professor, Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Elham
Saeedzadeh
Assistant professor, Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: One of the concerns about using of high energy photons in radiotherapy is neutron contamination production. The threshold energy of photoneutron production in most materials with high atomic number is about 7MeV. Therefore, it seems to be logical that the main components with high atomic number elements used in the LINAC head have a large contribution to the neutron contamination production. In this study, we investigated the neutron contamination flux of Varian Clinac 2100 machine and design a secondary shield to reduce the neutron contamination dose and flux.
Materials and Methods: The Varian Clinac 2100 linear accelerator with 18MV performance energy was simulated by the FLUKA Monte Carlo code. Percent depth dose (PDD) and dose profile curves was measured using a PTW thimble chamber to validate our mode. In a device with photon mode and 18MV performance energy, materials with low and moderate atomic number, such as water and polyethylene, play an effective role in slowing down the fast neutrons. Slow neutrons are easily absorbed by the certain materials, such as boron. In this research, four different materials of water, polyethylene, borated polyethylene and zirconium borohydride which have been considered as suitable neutron shield in previous studies, have been design as a second shield. The shield is designed with a cylindrical shape and with a thickness of 5 cm around the LINAC head elements.
Results: Because of hydrogen and zirconium atoms, the zirconium borohydride is more effective in slowing down the fast neutrons. Also, the boron absorbs the slowed down neutrons. Furthermore, the process of absorbing neutrons does not produce a significant secondary gamma. Using zirconium borohydride, the neutron flux around the LINAC is reduced more than 70%. Also, the neutron contamination dose in out-of-field areas in water phantom are reduced by 81%, which increases the safety of linear accelerators for patients and personnel significantly.
Conclusion: We can conclude that among the four materials used for the neutron shielding In this study, the zirconium borohydride has a good shielding properties against the neutron contamination.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
137
137
https://ijmp.mums.ac.ir/article_12631_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12631
Neutron Contamination Unexpected Dose in Varian LINAC
Mohammad
Ashrafinia
MSc student, Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran 09127210958, mohammad.ashrafinia@srbiau.ac.ir
author
Asghar
Hadadi
Assistant professor, Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Dariush
Sardari
Assistant professor, Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Elham
Saeedzadeh
Assistant professor, Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: Neutron contamination is very harmful for the patients receiving radiation therapy due to the high relative biological effect of neutrons. Medical linear accelerators head are made up of materials with high atomic numbers, and High-energy photons interaction with heavy materials can produce neutron contamination. In this study, neutron equivalent dose, neutron spectrum, and the effect of field size on neutron contamination dose is calculated by the FLUKA Monte Carlo code system.
Materials and Methods: In this study, all parts of the Varian Clinac 2100 accelerator head’s elements, such as target, flattening filter, jaws, MLC, shields, primary and secondary collimators are simulated by the FLUKA code system. LINAC performance energy was considered 18MV and a water phantom with dimension of 140×140×35 cm3 was simulated for neutron dose calculation. To investigate the effect of field size on neutron contamination, larger treatment fields such as 10×10, 20×20, 30×30 and 40×40 was formed by the jaws, and the smaller ones like 1×1, 3×3 and 5×5 was formed by the MLC.
Results: The results show that the Neutron contamination dose can be up to 2.54 mSv per 1Gy photon dose at isocenter. Neutron to photon dose ratio is 0.004 at isocenter and more than 8.6 in out-of-field areas. Furthermore, the neutron dose changes at the surface of the water phantom is only 15% that show the protective elements of the LINAC head are not able to control the neutron contamination flux. The most of neutron dose distribution is at the surface of the water phantom, So it can increases the secondary cancer risk in patients, including skin cancer. The effect of treatment field size on neutron contamination shows that the larger field size formed by the jaws contribute to higher in-field neutron dose, and using of smaller field size formed by the MLC, cause the lower in-field neutron dose.
Conclusion: The neutron contamination dose can not be neglected, and the effective parameters in neutron contamination exasperation should be thoroughly investigated. Furthermore, the harmful effects of the neutron contamination should be minimized by the appropriate protective shields
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
138
138
https://ijmp.mums.ac.ir/article_12632_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12632
Small field size dose-profile measurements: A comparison between Eclipse™ treatment planning system with NIPAM polymer gel dosimeter dose measurement
Vahid
Anaraki
Medical Radiation Department, Islamic Azad University, Science and Research Branch, Tehran, Iran.
author
Seyed Mohammad Mahdi
Abtahi
Physics Department, Imam Khomeini International University, Qazvin, Iran, Tel: +98-28-33901345, Fax: +98-28-33780040; smabtahi2007@gmail.com; sm.abtahi@sci.ikiu.ac.ir
author
text
article
2018
eng
Introduction:
Three physical conditions caused an external beam designated as a small field. The first is the loss of lateral charged particle equilibrium. The second is the effect of collimators on the primary photon source occlusion. The third condition is the size of the detector which is large compared to the field size. The most obvious perturbation effects in last condition is volume averaging. The aim of this study was to investigate dose distribution for small field sizes using NIPAM polymer gel dosimeter through MRI technique.
Materials and Methods: NIPAM polymer gel production: To fabricate NIPAM gel dosimeter at first, the gelatin (5 wt %) completely dissolved in 90% (80.1 wt %) of the water at 50 °C. Approximately 3 wt. % of Bis was dissolved at 50 °C. The N-isopropylacrylamide (3 wt%) was added after the gelatin–cross linker mixture was cooled to almost 37 °C. THPC (10 mM), as the antioxidant, was mixed with the %10 remnants of water, and was added to the solution. After preparation, the gel tubes were stored at temperature of 4- 7 °C in a refrigerator for 12 h.
Irradiation: Irradiation experiments were performed by a 6 MV X‑rays generated by a 2100C/D Varian linac. The vials filled with calibration NIPAM gel dosimeters were positioned fixedly in floor a 20×20×15 cm3 water phantom. Also, 5 cm Perspex slab was placed under the water phantom to ensure a full photon scattering condition.
For small field investigating a Perspex cubic phantom with dimensions of 7×7×7 cm3 filled with NIPAM polymer gel dosimeter. The phantom was irradiated using three perpendicular field with size of 1×1 cm2.
Response readout: The response of NIPAM polymer gel dosimeter was readout using a 1.5 T MRI scanner (Siemens Avanto, Germany). To scan the polymer gels a 32-echo Carr-Purcel-Meiboom-Gill (CPMG) pulse sequence was applied.
Results: Calibration curve of NIPAM polymer gel dosimeter was obtained. Equation (1) represents the variation of the R2 of the NIPAM polymer gel dosimeter a function of absorbed dose.
R2=0.208×Dose+1.925 (1)
Radiation dose profile in depth of 35 mm in NIPAM polymer gel dosimeter was compared with that calculated using Eclipse™ treatment planning system.
Conclusion: Results confirmed an accordance between dose profiles measured using polymer gel dosimeter and that calculated by TPS. Results showed a maximum difference of 3.8% between dose profiles calculated using TPS and measured by polymer gel dosimeter.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
139
139
https://ijmp.mums.ac.ir/article_12633_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12633
Reduction of photon contamination in electron therapy of cancer with magnetic fields
Mohammad Javad
Tahmasebibirgani
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
Departments of Clinical Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammad Ali
Behrooz
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mansour
Zabihzadeh
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Hojatollah
Shahbazian
Departments of Clinical Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Reza
Maskani
School of Paramedicince, Shahroud University of Medical Sciences, Shahroud, Iran. Tel:
+989124734697
Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Jafar
Fatahiasl
Department of Radiology Technology, School of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Nahid
Chegeni
Departments of Clinical Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction:
Photon contamination is a restriction on treatment with electron that increase dose to healthy tissue below the tumor. The aim of this study is to reduce the photon contamination using a magnet system.
Materials and Methods:
A mini-applicator equipped with two neodymium boron permanent magnets was designed which make it possible to adjust the distance between magnets. Mini-applicator was placed in standard applicator of Varian 2100 CD linear accelerator. Mini-applicator was modeled in CST studio finite element software. Deflection angle and displacement of electron beam transporting through magnetic field were calculated. Different transverse magnetic intensities were created by determining the amount of 2 to 5 cm for distance between two poles. The treatment head was rotated to deflected electrons become normal to the water surface. Dosimetry was performed in a water phantom using EBT2 gafchromic film. Films were scanned with HP G3010 reflecting scanner. Optical density in red channel was extracted by programming in MATLAB. Dose curves in presence of magnetic field compared with frame without magnetic field.
Results:
Simulated and measured magnetic field intensities are consistent. Maximum deflection angle is 32.9 degree for 12 MeV and minimum deflection is 12.1 degree for 15 MeV electron beam. Scanned film showed clearly that photons exit from electron field. The photon contaminations without magnetic field were 4.5 and 2.6 percent for 15 and 12 MeV respectively which using highest magnetic field intensity have decreased to 0.9 and 0.2 percent.
Conclusion:
A magnetic mini-applicator was created and modeled using finite element method. The deflection angle and displacement of electrons beam was calculated. By applying magnetic field, photon contamination can be reduced. Energetic electrons can be used without concern for adverse effects on healthy depth tissue.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
140
140
https://ijmp.mums.ac.ir/article_12634_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12634
Evaluation of dosimetry a performance parameter for a homemade farmer-type ionization chamber according to IEC60731
Zahra
Saberi
MSc in Medical Radiation Engineering, Department of Radiology, Faculty of Engineering, Islamic Azad University, Research Branch, Tehran, Iran. Tel: 09124688658, Fax: 02634257058, Email: z.saberi97@yahoo.com
author
Kourosh
Arbabi
Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI),
Secondary Standard Dosimetry Laboratory (SSDL), Pars Isotope Co., Karaj, Iran,
author
text
article
2018
eng
Introduction: Due to its simplicity, fast response and high reliability, ion chamber detectors
are one of the most suitable dosimetry instruments for X and gamma rays. The dosimeter
of photon beams, which used in radiotherapy centers, requires high accuracy and should pass requirements of IEC 60731 standards. About 80 percent of the IEC 60731 standard tests such as stability, leakage current, the dose-response linearity, repeatability and resolution were assessed and the results were compared with the values reported by the standard. All tests were carried out on the PTW-30001 Farmer-type chamber and the response was compared with the manufactured chamber.
Materials and Methods: In this study, according to the IEC 60731, IAEA guidelines and standards, using Cobalt-60 gamma radiation, the dosimetric and functional parameters of an ionization cavity detector of a cylindrical Farmer-type with sensitive volume of 0.6 cc, (homemade 0.6 cc Cylindrical Ionization Chamber), compared and calibrated against the calibrated reference Farmer chamber response (PTW-30001).
Results: By applying minimum dose, leakage current was ±0.35 % and It was reduced by less than 1 % after radiation exposure. The percentage change in stability was ±0.3 %. Angular dependency in the chamber response was +0.2 %. Temperature effect on chamber reading was +0.2 % and the repeatability error was ±0.2 %.
Conclusion: Unlike a simple look, Farmer-type chambers have their own technical complexity and cannot easily be used as a dosimeter by doing a few simple tests. Therefore, the IEC 60731 has been developed to address these complexities and introduce them as requirements for the application of an ionization chamber. The present work was a part of the project of manufacturing and commercializing a Farmer-type ionization chamber at the Nuclear Science and Technology Research Institute (NSTRI) in order to face the ahead challenges and try to resolve them. Most of the challenges that come from the technical knowledge and experience can be solved. All of the tests performed well with the standard requirements, but at the same time, compared to the reference ion chamber performance. There was negligible difference between the PTW reference chamber and the criteria required in the standard which demonstrates well-designed PTW chamber.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
141
141
https://ijmp.mums.ac.ir/article_12635_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12635
Radiolabeling and Biodistribution of new dual modality nanoparticle probe in Nuclear Medicine
Saleh
Salehi Zahabi
Assistant Professor in Medical Physics, Department of Radiology and Nuclear Medicine, Kermanshah University of medical sciences, Kermanshah, Iran. Email: Saleh.salehizahabi@kums.ac.ir, Tel: +98 9183882308
author
Hossein
Rajabi
Assistant Professor in Medical Physics, Department of Radiology and Nuclear Medicine, Kermanshah University of medical sciences, Kermanshah, Iran.
author
Samira
Rasaneh
Assistant Professor in Medical Physics, Department of Radiology and Nuclear Medicine, Kermanshah University of medical sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: Dual-modality contrast agents, such as radiolabeled nanoparticles, are promising candidates for a number of diagnostic applications, namely SPECT imaging with MR imaging. So the aim of study was evaluating potential of Chitosan-Coated Magnetic Nanoparticles(SPION) labeled with 99mTc as new Dual-modality probes for liver Imaging.
Materials and Methods: In this study chitosan particles were coated on SPION and radiolabeled with 99mTc after Purification. The quality control tests including determining particles size, labeling efficiency, stability and Biodistribution study in the mice were performed. Finally MRI and nuclear medicine imaging study in Balb/c mice in 1 and 4 hour after injection of complex were performed.
Results: Results showed that the final complex have spherical shape and with average size 255±30nm. The labeling efficiency and stability of complex with 99mTc were 89±6%, 93±6% respectively. Biodistribution study, MRI and nuclear medicine imaging showed high accumulation of Complex in liver.
Conclusion: The results showed that the 99mTc-Chitosan coated SPION may be considered as promising Dual-modality probes for liver Imaging.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
142
142
https://ijmp.mums.ac.ir/article_12636_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12636
Review and Performance Comparison of Lead-Free Shields and Lead Shields, In Terms of Biological Effects in Nuclear Medicine by the Comet Method
mohsen
bakhshandeh
Department of Radiology, Faculty of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Masoomeh
Barzegar Ziyarani
Master of Radiobiology and Radiation Protection, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Mehdi
Allahbakhshian-Farsani
Departmentof Hematology and Blood Banking, Faculty of Allied Medicine, Shahid Beheshti University of Medical Sciences, Tehran
author
Ehsan
Bakhshandeh
Department of Polymer Processing, Iran Polymer and Petrochemical Institute, Tehran, Iran
author
Nezhat
Shakeri
Department of Biostatistics, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran
author
text
article
2018
eng
Introduction: Ionizing radiation can cause damage to biologically important DNA molecules. Radiation in nuclear medicine radiation exposes people working in from two main positions; administer in gradiopharmaceuticals (the barn and squeezing a generator, procurement, distribution and drug infusion) and patients that receive radiation treatment (patients that are prescribed a radiopharmaceutical). Use of lead aprons is disputed practice in radiation treatment due to the creation of special lead X-rays of high-energy gamma ray collisions and the high absorption coefficient of such radiations in the body. Correct use of personal protective equipment, such as uniforms and flexible protection, and compliance with radiation protection can greatly reduce damage. Flexible lead shields are usually made from materials such as rubber; polymers or elastomers (polymers that are elastic) are used as the basis for fine lead particles. The problems with lead shields have led to recent discussion of the use of lead-free shields. If the biological effects caused by lead-free shields give less than two states with and without a lead shield, the shield that is lighter, weaker and that doesn’t cause environmental pollution, can be used in place of lead.
Materials and Methods: To review and achieve the above objective, blood samples were taken from non-radiation operatives and poured in heparin tubes, and then placed in the considered distance of time and place; after radiation, they were exposed to gamma radiation resulting from technetium, comet assay will be performed on them.
Results: density was super less dense compared to the lead and was about one-tenth of the density of lead (1.23). DNA damage in both groups (with and without a lead shield) is greater when compared with the control group.
Conclusion: By using two-way analysis of variance, the time variable was significantly effective in increasing the damage. In addition, the type of shield variable (lead or lead-free) and meaningful distance have not shown.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
143
143
https://ijmp.mums.ac.ir/article_12637_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12637
Determination of geometric accuracy of radiotherapy fields by port film and DRR using Matlab Graphical User Interface
Seyyed Mostafa
Anjam
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran. , Tel: 09203040443,
author
Nooshin
Banaee
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran. ,
author
Hassan Ali
Nedaie
Cancer Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Radiation therapy is one of the methods of cancer treatment. In this method, it is necessary to avoid harming the healthy tissues of the patient which is in the vicinity of the target, as much as possible. Treatment verification is one of the most important steps of radiation therapy which has two usual methods, using Port film and EPID. The accuracy and precision of treatment in EPID-less centers are usually of concern. By entering EPID into the treatment verification process, no more studies have been done for increasing the precision of treatment verification by using port film. The purpose of this study is to determine and verify the exact location of radiation therapy fields by using port-film and DRR as low cost
equipment.
Method and Materials: Initially, by writing appropriate algorithm for port film in the megavoltage irradiation, detectable contrast was created for the image and then by using appropriate markers and developing program by MATLAB as DRR Port Registration, Semi-automatic and automatic registration between port- film and DRR images were performed for Pelvic and Chest phantoms and the results were compared withEPID consequences in similar conditions.
Results: By using this software, DRR and port film as treatment verification tools, the precision of treatment verification and accuracy of radiation therapy fields were achieved in the extent of the millimeter. The study of validation results with EPID demonstrated that the mean absolute average error in angle is equal to 0.5926 degrees, 1.703 mm in the X direction and 2.42716 mm in the Y direction. Also, the mean absolute average errors in MATLAB validation is equal to 0.2 degrees, 0.75 mm in the X direction and 0.81 in the Y
direction and 0.228% in scale.
Conclusion: The results of this study illustrated that using this software and suitable low-cost hardware in the centers with lack of EPID can increase the precision of treatment verification to the millimeter and it can be introduced as a suitable alternative for EPID in centers for increasing treatment accuracy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
144
144
https://ijmp.mums.ac.ir/article_12638_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12638
Commissioning the First Mobile Dedicated Accelerator for Intraoperative Electron Radiotherapy in Iran
Hamid Reza
Baghani
Physics Department, Hakim Sabzevari University, Sabzevar, Iran.
author
Mostafa
Robatjazi
Department of Medical Physics and Radiological Sciences, Sabzevar University of Medical Sciences, Iran
author
Seyed Rabi
Mahdavi
Medical Physics Department, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Intraoperative radiotherapy is a radiotherapy technique in which a high single fraction of radiation dose is delivered to the patient after surgery and Concurrent with anesthesia time. The most frequent method for IORT implementation is Intraoperative electron radiotherapy (IOERT), in which, some dedicated and high dose per pulse electron accelerators are employed for radiotherapy. Recently, Iran is also equipped to these dedicated machines for IOERT. Commissioning procedure of this dedicated IOERT machine and dosimetric characteristics of intraoperative electron beam have been evaluated in current study.
Materials and Methods:
LIAC accelerator, a mobile dedicated IOERT machine with the maximum energy of 12 MeV, was commissioned in this study. Commissioning procedure was performed inside a MP3-XS automatic water phantom which is introduced for small field dosimetry. 10 cm diameter reference applicator was considered and applicator edge was in contact to the phantom surface. All of measurements including percentage depth dose (PDD) along clinical axis, transverse dose profiles (TDP) at the depth of maximum dose and output factors (OF) were performed using ionometric dosimetry. During the measurements, Advanced Markus and Semiflex ion chambers were employed as field and reference detector, respectively. All of the obtained data were processed and analyzed using Mephysto Navigator software.
Results:
Measured PDDs showed that the intraoperative electron beam has a steep dose fall-off gradient which increases with decrement of electron energy. This fact can effectively spare the underlying healthy tissues. The symmetry and flatness of obtained TDPs at all studied energies were less than 2% which can improve the dose uniformity inside the tumor bed. As expected, the OFs were increased with increment of electron energy, but In contrast to the conventional accelerator, OF values reduce at greater radiation field sizes.
Conclusion:
According to the obtained results, it can be concluded that dosimetric characteristics of intraoperative electron beam are quite favorable regarding to the mandatory issues which should be satisfied in intraoperative radiotherapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
145
145
https://ijmp.mums.ac.ir/article_12639_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12639
Statistical Review of Theses in Iran Public Universities in Medical Imaging Field
Alireza
Lari
School of Electrical Engineering and Robotics, Shahrood University of Technology, Shahrood, Iran. Tell: 09301515016
author
text
article
2018
eng
Introduction: In spite of all the researches on medical imaging, this field is still hot. It is the third major area of research, conducted in the world. Unfortunately, there is no statistical evaluation available of the student theses in Iran. It does not seem like a policy is going to be established to address this issue. Providing a statistical insight to activities done in the past ten years, analysis and classification of the theses in this field are of the research steps of this paper.
Materials and Methods: After identifying the research fields of medical imaging, and the study programs and the universities offering them, and filtering as needed, three disciplines of biomedical engineering, medical physics and medical radiation were pinpointed in 16 public universities in Iran consisting of universities of medical sciences and engineering offering the usual bachelor, master’s degree and PHD. After the extraction of the students’ theses titles in those universities, having checked the flow of subjects in years 2006 to 2016, the theses were classified into seven most frequent areas consisting of CT, Ultrasound, MRI, Nuclear, Radiography, Infrared and Software development.
Results: Checking the gathered data, the highest number of theses among the three, belong to Biomedical Engineering major. Also, among the 16 universities, most of the titles belong to Amirkabir University of Technology which is considered the of Biomedical engineering center of excellence in the country.
If we divide the imaging researches into subsections, we will find out that most of the researches about CT have been conducted in Tehran University of Medical Sciences and about MRI in Tehran University, about Nuclear Imaging and Radiography in Shahid Beheshti University, about Ultrasound in Science and Technology University, and about Software in Tehran University.
Also, some theses (mentioned in the software section) have been merely about image processing and not pursuing any biomedical engineering purposes. In addition, among all the different areas of medical imaging, most of the titles have been around MRI.
Conclusion: Considering the number of these titles published in different fields, an increase in the number of titles in years 2012 and 2013 is evident. The list of probable reasons behind this rise includes university admissions of students and professors with medical imaging related specialties, scientific and practical backgrounds and equipment availability etc.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
146
146
https://ijmp.mums.ac.ir/article_12640_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12640
Expression of phosphorylated histone H2AX in blood lymphocytes of patients undergoing angiographic procedures following exposure to X‐rays
Alieh
Alipoor
MSc Radiology Department, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran, E-mail: alipoor777@gmail.com
author
Reza
Fardid
Associate Professor, Radiology Department & Ionizing and Non-ionizing radiation protection research center, School of Paramedical Sciences, Shiraz university of Medical, Sciences, Shiraz, Iran, E-mail: rfardid@sums.ac.ir
author
text
article
2018
eng
Introduction: Coronary angiography is a Diagnostic-Therapeutic method involving ionizing radiation. This method causes to DNA damage with form double stranded breaks which is followed by the phosphorylation of the histone, H2AX. H2AX is a key factor in the repair process of damaged DNA which will accumulate to damage sites. In human cells, H2AX constitutes about 10% of the H2A protein which is unique due to carboxyl tail. H2AX the phosphorylated on serine 139 in DNA damage sites. Phosphorylated H2AX protein is called γ-H2AX.
Materials and Methods: The present study was performed experimentally, after ethics committee approval and written informed consent, twenty-four patients with coronary syndromes, scheduled for Coronary angiography entered into the study. Blood samples from twenty-four patients (mean age 58.16 years) were collected before and 10 minutes after ionizing radiation exposure. Lymphocytes were isolated, fixed and the phosphorylated histone stained with specific monoclonal antibody and analyzed for mean fluorescent intensity using a flow cytometer. Data were analyzed with linear regression, Pearson correlations and Paired t- tests. P<0.05 was considered to be significant.
Results: Blood samples of patients after irradiation showed a significant increase in mean fluorescent intensity compared to before radiation exposure (p<0.001). A significant correlation was shown between dose and mean fluorescent intensity after irradiation (r=0.73, p<0.001)
Conclusion: DNA double stranded breaks are the most significant damages among DNA lesions induced by ionizing radiation. It is a great interest in field of radiology to minimize the risk of adverse radiation effects associated with coronary angiography procedures. γ-H2AX is a very sensitive method of measuring radiation-induced DNA double strand breaks in the doses of coronary angiography. In the present study, we applied γ-H2AX to assess the DNA damage during coronary angiography procedures and their effects on DSB.
We found a significant increase of γ-H2AX in blood lymphocytes of 24 patients after Coronary angiography.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
147
147
https://ijmp.mums.ac.ir/article_12641_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12641
Influence of Compensator Thickness and Field Size on Buildup factor of a Brass Compensator for Intensity- Modulated Radiation Therapy
Elnaz
Balvasi
Master of Medical Physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran Email: e_balvasi.ph87@yahoo.com, Tel: +98 9169600536
author
Abbas
Haghparast
Doctor of Medical Physics, Department of Medical Physics, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Peyman
Hejazi
Doctor of Medical Physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran
author
text
article
2018
eng
Introduction:
Radiotherapy is one of the effective methods in the treatment of cancer. In the recent methods of radiotherapy, intensity modulated radiotherapy (IMRT) technique by compensators is used. when photon beam passes the compensator, scattered photons can be generated within the compensator. The presence of scattered photons may complicate the design of compensators as well as the subsequent calculations of dose distributions. The buildup factor, ‘B’, is one of these important properties of a material to be used for compensator construction. It directly affects the dose quantity.
Materials and Methods:
Radiotherapy is one of the effective methods in the treatment of cancer. In the recent methods of radiotherapy, intensity modulated radiotherapy (IMRT) technique by compensators is used. when photon beam passes the compensator, scattered photons can be generated within the compensator. The presence of scattered photons may complicate the design of compensators as well as the subsequent calculations of dose distributions. The buildup factor, ‘B’, is one of these important properties of a material to be used for compensator construction. It directly affects the dose quantity.
Results:
Our results indicated that the compensator thickness and field size have the most significant effect on the calculation of buildup factor for the 6-MV photon beam.
Conclusion:
Influence of compensator thickness and field size on calculation buildup factor can reduce the error due to delivered dose to target volume and organs at risk
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
148
148
https://ijmp.mums.ac.ir/article_12642_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12642
Mega Voltage Cone Beam Computed Tomography (MV- CBCT) using a Standard Medical Linear Accelerator and EPID: A feasibility study.
Fateme
Shahedi
M.Sc., Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran
author
Mahdi
Mommen nezhad
PhD, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.Tel: +98-51-38002319, 51- 38828576,
author
Hossein
Akbari
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mahdi
Jamali
M.Sc., Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
author
shahrokh
Nasseri
Mashhad University of medical Sciences
author
text
article
2018
eng
Introduction: The success of radiotherapy cancer treatment delivery depends on the accuracy of patient positioning for each treatment session. A number of kilovoltage x-ray volumetric imaging modalities with an additional source and detector have been developed to allow patient set-up verification based on the internal anatomy, but a significant portion of medical linacs are only equipped with electronics portal imaging device (EPID) as a planar imaging system. The aim of this study is investigating the feasibility of megavoltage cone beam computed tomography (MV-CBCT) using medical linac and EPID to obtain volumetric data for 3D representation of patient in treatment position.
Materials and Methods: The MV-CBCT system consists of an amorphous silicon EPID with an active area of 41×41 cm2 attached to an Elekta Precise linac. Initially, the quality control tests were performed to evaluate the safety features, mechanical stability and quality of the megavoltage imaging system. The MV-CBCT scanning protocol was divided into three major parts. In the first part, Step and Shoot delivery mode was used to acquire projections of an anthropomorphic head phantom and quality assurance phantom in increments of 30 with 3 MU and x-rays of 6 MV energy over 3600 of gantry rotation. Afterwards, noise reduction was conducted by applying 2D adaptive wiener filter to projections. Furthermore, it is found that scatter produces cupping artifacts and increase uniformity variations across the reconstructed tomograms. Therefore, a scatter correction method which is based on a superposition of Monte Carlo generated scatter kernels was applied to the portal images. In the latest part of the research, the Feldkamp cone-beam algorithm used to reconstruct the 2D portal images to a 3D image, then, image quality characteristics such as; uniformity, contrast-to-noise ratio (CNR) and spatial resolution were investigated using the Gammex phantom
Results: The safety interlocks were found to be functional. The EPID response uniformity was within 97% across the detector. Contrast resolution of the MV imaging system was found to agree with the recommended tolerance; and the value of f50 for spatial resolution was 0.41lp/mm for 6 MV. The supporting arm deviation was within ±1 mm, and corrections are required to realign the projections. Reconstructed slices from the spatial and contrast resolution modules of the Gammex phantom shown that the 4 lp/cm section was clearly resolvable, and also bone, air, polyethylene, and acrylic inserts can be clearly resolved, with bone and air having the greatest and polyethylene having the lowest contrast, which improved after scatter correction. Furthermore, the maximum uniformity variation was determined of 15.75%-pixel intensity units which reduced significantly after scatter correction.
Conclusion: The result of this study has demonstrated that EPID can be used to acquire volumetric images with high enough quality to improve patient alignment prior to dose delivery.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
149
149
https://ijmp.mums.ac.ir/article_12643_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12643
Fast System Matrix Calculation in CT Iterative Reconstruction
Golshan
Mahmoudi
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
author
Mohammad Reza
Ay
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
author
Hossein
Ghadiri
1. Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Iterative reconstruction techniques provide better image quality and have the potential for reconstructions with lower imaging dose than classical methods in computed tomography (CT). However, the computational speed is major concern for these iterative techniques. The system matrix calculation during the forward- and back projection is one of the most time- consuming components. In this study we propose a method for fast system matrix calculation based on line integral model (LIM) in a simultaneously algebraic reconstruction technique (SART) framework. This method has generality to extend to finite size beam and 3D geometry. Also we use our LIM based method to approximate the area integral for area integral model (AIM) based method.
Materials and Methods:
First, we calculate the contributing detectors for a given pixel and a given projection view. Then, the lengths of the intersection line from these detectors with the pixel are calculated using an efficient method. To approximate area integral, a narrow fan beam is modeled by several lines that connect the source to one detector cell. Finally the computed system matrix was evaluated by reconstructing the image of a numerical Shepp-Logan phantom, using SART.
Results:
Overall, numerical results show that our LIM-based method is faster than the Siddon algorithm. Our AIM-based method results in better image quality than LIM-based method but more time consuming.
Conclusion:
The authors have proposed fast algorithm to calculate system matrix, which are extendable for the finite-size beam and 3D geometry. The algorithm has the potential for parallel computing.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
150
150
https://ijmp.mums.ac.ir/article_12650_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12650
Estimation of the thyroid secondary cancer risk on the patient of standard breast external beam radiotherapy
Zeinab
Momeni
Medical Physics Department, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Maryam
Atarod
Medical Physics Department, School of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran
author
text
article
2018
eng
Introduction:
The purpose of this study was to estimate the secondary cancer risk of thyroid for standard radiotherapy methods which are commonly used for breast cancer patients.
Materials and Methods:
Sixty-four breast cancer patients (their age range was around 50 years old) who referred to Seyed- Al- Shohada hospital (Isfahan, Iran) were included in this study. The radiotherapy of the mentioned patients was performed using 6 MV photon beams. Dose measurements were also done using thermoluminescent dosimeters (TLD). Calculation of the risk of developing secondary cancer in thyroid, was done using the Biological Effected of Ionizing Radiation Committee (BEIR VII) and recommended quantity of International Radiation Protection Commission (ICRP), Excess Relative Risk (ERR).
Results:
The mean radiation dose to thyroid for the tangential beams, tangential field with Supraclavicular field, and also tangential field with Supraclavicular field in mastectomy (MRM) were 0.883 ± 0.472, 1.512 ± 0.365 and 1.587 ± 0.37, respectively. The risk of developing secondary thyroid cancer over a period of 5 years after breast cancer therapy in the tangential, tangential with supraclavicular field, and also tangential beams with supraclavicular field in MRM was 9.974 ± 4.318, 17.891 ± 0.365 and 18.783 ± 4.384, respectively. The mean of the measured thyroid doses in patients treated with tangent fields was significantly lower than the patients under the irradiation of the tangent fields with supraclavicular field (P <0.001).
Conclusion:
Using radiation protection equipment is suggested for breast cancer patients who treated with the studied radiotherapy methods.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
151
151
https://ijmp.mums.ac.ir/article_12651_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12651
Optical Imaging of the Motor Cortex in the Brain in Order to Determine the Direction of the Hand Movements Using Functional Near-Infrared Spectroscopy (fNIRS)
Maziar
Jalalvandi
Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
author
Nader
Riahi Alam
Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran,
author
Hamid
Sharini
Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
author
Hasan
Hashemi
Advanced Diagnostic and Interventional Radiology, Research Center(ADIR) , Tehran , Iran.
author
Soosan
Kohzad
National Brain Mapping Labaratory, Tehran, Iran.
author
text
article
2018
eng
Introduction:
In recent years, optical imaging has attracted a lot of attention from scholars as a non- aggressive, efficient method for evaluating the activities of the motor cortex in the brain. Functional near-infrared spectroscopy (fNIRS (is a tool showing the hemodynamic changes in a cortical area of the brain according to optical principles. The present study has been designed to investigate and evaluate the cortical activities of the brain during the performance of hand motor tasks which we have a lot every day.
Materials and Methods:
In the present research, the activity of the motor cortex in the brain was investigated during the vertical and horizontal movements of the right hand. To carry out the purpose of this study, 6 healthy right-handed volunteers (25-40 years of age) were used. The required data were collected using a 48-channel fNIRS device compatible with MR (OxyMonfNIRS manufactured by Artinis) with two 763 and 845 nanometer wavelengths. 8 infrared transmitters and 8 infrared receivers, constituting 20 channels in all, were used for the purposes of the experiment. The distance between the transmitters and receivers was 30 mm and a sampling frequency of 10 Hz was also chosen. The obtained data were processed and analyzed using the NIRS_SPM toolbox.
Results:
The results demonstrated that the hemodynamic signal intensity in the motor cortex in the brain during the performance of motor tasks was significantly increased (p≤0.05) in comparison to the state when body is resting. The study findings showed that the activation map for the activities related to the direction of the movement's performance in the motor cortex in the brain are spatially separate and distinguishable, and the highest level of activity was recorded in the primary motor cortex (M1) area.
Conclusion:
The results of this research demonstrated that it is possible to distinguish the various directions of hand movements using Functional near-infrared spectroscopy (fNIRS) signals. The existence of direction-dependent activation in the motor cortex in the brain helps develop the idea that this part of the brain cortex not only controls the movements of the various parts of the body, but also has a role in processing complicated information such as distinguishing between the various directions of hand movements. The results obtained from this research may also be useful to further studies on movement control
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
152
152
https://ijmp.mums.ac.ir/article_12653_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12653
Consideration of accurate dose distribution for Contura balloon catheter in breast brachytherapy with MCNP5 simulation
Maryam
Papie
Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
author
S
Sina
author
R
Faghihi
Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
author
text
article
2018
eng
Introduction:
Contura is a balloon applicator that used to deliver intra cavity radiation for Partial Breast Irradiation (PBI) treatments. Contura with 4 peripheral lumens surrounding the central, for loading HDR sources from an after loader system can provide an asymmetric dose distribution and gives a more flexible shape of dose than earlier balloon applicators such as Mammo site. Accurate dosimetry is necessary to avoid deviations in delivered dose from that prescribed for a successful treatment. In this study we tried to explore possible uncertainties in simple water phantom measurements compared to the realistic breast cancer treatment condition with Contura.
Materials and Methods:
MCNP5 simulations were performed to have investigations on dose distribution. Several trials have been introduced to study the effects of corrections for phantom geometry and content. First, dose distributions were considered for an ICRU-44 breast phantom and the obtained results were compared with water. In next trial geometry was corrected to take the effects of an air cavity as lung inside the chest into account. Investigations were followed in third trial with correction at the breast skin surface to evaluate tissue-air interferences at skin. 192-Ir HDR sources were simulated on 7 dwell positions on each lumen. Lumens were defined inside a water sphere as saline filled balloon. Results have presented as dose distribution plots in breast and dose volume histogram analysis for PTV.
Results: The ICRU-44 breast phantom demonstrated differences less than 1% in breast from water. Air cavity as the lung tissue has not shown significant effects on dose distribution in the breast, but correction at skin surface has caused up to 5% overestimations proximity near this area. However almost in other places in the corrected breast, the matched results to the water phantom have been observed.
Conclusion: The results of this investigation indicate no significant deviations from a water phantom without any corrections. Therefore, treatment planning systems can still be used without significant uncertainties in treatment of breast cancer using HDR brachytherapy with Contura device. Differences can be corrected to provide a precise dosimetry but because of underestimated values obtained in water phantom dosimetry it can be a conservative approximation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
153
153
https://ijmp.mums.ac.ir/article_12654_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12654
A study on dosimetry accuracy of Strut-Adjust Volume Implant (SAVI) brachytherapy
M
Papie
Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
author
S
Sina
Radiation Research Center, Shiraz University, Shiraz, Iran.
author
R
Faghihi
Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
author
text
article
2018
eng
Introduction:
Accelerated Partial Breast Irradiation (APBI) is an effective treatment for breast carcinomas because of its limited number of fractions. Strut-adjusted volume implant (SAVI) is a HDR brachytherapy applicator to deliver the prescription dose with good PTV coverage and acceptable dose to skin, chest wall and organ at risks. Acceptable clinical outcomes depend on accurate dosimetry methods. Currently water is used as the reference dosimetry phantom material in treatment planning systems. The purpose of this study is to consider the corrections on phantom material and geometry in dose distribution of SAVI brachytherapy simulation using MCNP5 Monte Carlo code.
Materials and Methods:
SAVI with 8 peripheral source channels were considered expanded inside the lumpectomy cavity in breast. Three realistic phantoms were employed to perform the step by step corrections and dose distributions were compared with that of water. Considerations were included using the ICRU-44 defined breast material as the real breast composition and moreover the air-tissue interferences at the skin, lung and the air cavity inside the SAVI were studied.
Results:
According to the results, the dose differences due to the breast material corrections were less than 1% in the most points of breast and only 2-3% overestimation were observed close to the skin. Breast phantoms containing air cavity have shown up to 2% decreases in regions around it. Finally a phantom with both noted corrections and a curved surface for breast skin, corrected the calculations with about 3-5% underestimations at skin.
Conclusion:
According to the results of this study, dose distributions in breast phantoms containing different materials does not differ significantly with the dose distribution in water phantom. Conservative approximations can be provided with water phantom and it doesn’t seem necessary that the current treatment planning systems be replaced with the model-based patient specific dosimetry methods.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
154
154
https://ijmp.mums.ac.ir/article_12656_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12656
Monte Carlo investigation on precise dosimetry of HDR breast brachytherapy with Accuboost
Maryam
Papie
Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
author
S
Sina
Radiation Research Center, Shiraz University, Shiraz, Iran.
author
R
Faghihi
Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
author
text
article
2018
eng
Introduction:
Accuboost is a HDR brachytherapy system in early stages breast cancer treatment. This device provides a completely noninvasive procedure with parallel-opposed radiation from two immobilizing peripheral applicators that caused it a preferred option of modalities to choose. In most commercial treatment planning systems, tissues are considered as a simple water phantom. Inaccuracies arised from geometry and compositions can lead to deviations in interested dose distribution. This study intends to simulate HDR breast brachytherapy with Accuboost device in order to consider requirement corrections to have an accurate treatment dosimetry.
Materials and Methods:
MCNP5 simulation is employed to model phantoms in dosimetric measurements. We tried to take geometrical corrections into account in three phantoms. Dose distributions as dose volume histogram parameters and isodose plots obtained from these phantoms are compared to those of water. Corrections are included using real breast tissue with ICRU-44 breast composition, chest defined with an air cavity as lung and a curved surface to introduce a more realistic contour for breast skin. Accuboost is simulated with radiations from eighteen HDR 192-Ir sources on each applicator with appropriate tungsten shields.
Results:
Differences in most regions with less than 1% to water and maximum value about 5 % have been observed in phantom with ICRU-44 breast material compared to the water. Lung presence have increased deviations a few percent but it has not significantly differed. In phantom with all corrections maximum differences are almost the same as both earlier and deviations with about 5-7% are found near the chest and around the breast skin not in contact to applicators.
Conclusion:
Based on the results, although discrepancies between corrected phantom and water phantom are in areas near the skin the main differences are in clinical accepted uncertainties and other points of tissue have shown accommodatian. Therefore essential correction may be not needed.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
155
155
https://ijmp.mums.ac.ir/article_12657_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12657
Optimization of an ultra-high-resolution rectangular pixelated parallel-hole collimator with a CZT pixelated semiconductor detector for HiRe-SPECT system
Samira
Abbaspour
Department of radiotherapy, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran.
author
Parvaneh
Darkhor
Department of Medical Physic, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Jalil
Pirayesh Islamian
Department of Medical Physic, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
author
text
article
2018
eng
Introduction: In nuclear medicine, the use of a pixelated semiconductor detector such as CZT is an of growing interest for introducing new devices. Especially, the spatial resolution can be improved by using a pixelated parallel-hole collimator with equal holes and pixel sizes based on the pixelated detector. The purpose of this study was to compare the effect of pixelated and non-pixelated parallel hole collimators and CZT detector on the functional parameters (including the spatial resolution and sensitivity) and the image quality of a HiRe- SPECT imaging system using SIMIND Monte Carlo program.
Materials and Methods: In this study we simulated a HiRe-SPECT small animal imaging system with a pixelated CsI (Na) detector (1×1×5 mm3) and evaluated the system functional parameters and image quality. The collimator features were included; hole diameter of 1.2 mm, septal thickness of 0.2 mm, and hole length of 34 mm. We designed the pixelated collimator with rectangular hole shapes and compared with non-pixelated Hexagonal parallel hole collimator (LEHR) based on CZT detector. In pixelated collimator, hole size and pixel size were the same (1×1 mm2). Then the planar scans of a 99mTc point source and SPECT scans of a digital mini Jaszczak phantom and liver scans of a voxelized MOBY mouse phantom were simulated with SIMIND. Slices were reconstructed using the maximum-likelihood expectation maximization (MLEM) with four iterations, matrix size of 128 × 128 × 128 and voxel size of 0.3 mm. The framework of CASTOR (Version 1.0) was used for the MLEM algorithm. We assessed the spatial resolution, sensitivity and image contrast to conclude an optimized HiRe-SPECT system.
Results: The results on simulations showed that the planar spatial resolution of the pixelated and LEHR parallel hole collimators was 2.4 and 3.6 mm in terms of full width at half maximum (FWHM), respectively. Also, the sensitivity of the LEHR and pixelated rectangular collimators calculated 34.04 and 15.15 Cps/MBq, respectively. To compensate the reduction sensitivity in pixelated collimator, the CZT semiconductor detector was used. The CZT detector improved the sensitivity about 1.7 times higher than this by the CsI (Na). The minimum detectable size of hot rods in mini Jaszczak phantom on the reconstructed images were determined in the sectors of 1.8 with the pixelated collimator, and 2.4 mm for the LEHR collimator at a 5 cm distance from the phantom. Image quality and contrast of the liver of MOBY phantom and hot rods in the mini Jaszczak phantom with pixelated collimator were obtained about 1.5 times better than the LEHR collimator.
Conclusion: Based on our results, we recommend the rectangular pixelated parallel-hole collimator for a high-resolution with a CZT pixelated semiconductor detector for improving
the sensitivity of HiRe-SPECT systems.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
156
156
https://ijmp.mums.ac.ir/article_12658_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12658
Compare the organs at risk in breast-conserving three- dimensional conformal radiotherapy (3D-CRT) based on patient's breast size
S
Yazdani
MSc of Medical Physics, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Mehran
Yarahmadi
Medical Physics Dept., Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
text
article
2018
eng
Introduction:
Breast cancer is the most common cancer among women. Radiotherapy plays an important role in the treatment of breast cancer and essential part of the standard treatment after breast-conserving surgery, routinely done to eliminate the microscopic residual cancer. The heart and lungs are one of the most important organs at risk of breast cancer radiotherapy that their exposure are unavoidable. Pneumonia and Pericardia are the most common complications of lung and heart radiation exposure, respectively.
Materials and Methods: In this study, 20 patients undergoing radiotherapy after breast-conserving surgery were studied. The mean age of patients was 45 years old in the range of 30-60 years. Patients were treated by 3D-CRT with a single-isocenter tri-field technique including two apposite tangent fields and a supraclave field. To optimize the dose distribution, the wedge with suitable angle was placed in front of the beam for each field. The heart and right and left lung in each slice were contoured based on RTOG by oncologist and physicist, and was reconstructed in three dimensions by treatment planning system (Isogry version 4.1). Dose-volume histogram (DVH) for organs at risk were calculated and extracted. Parameters V5, V10, V20, V30, V40 and also Dmax and Dmean for organs at risk were extracted. Patients were classified into two groups, large and small breasts; then statistical analysis was performed with the SPSS software.
Results: At all levels of the dose for the large breast group, a greater percentage of the heart was involved, but there was no significant statistical difference between the small breast group (p>0.05). In lungs, at all levels examined, the received dose of large breast group was higher than those of the small breasts, but this difference was not statistically significant (p>0.05). Only the Dmax parameter between the two groups was significant (p=0.01).
Conclusion:
The received dose of organs at risk, better results were obtained in a small breast; but no threshold of exposure risks. Therefore, paying attention to this group of patients is more clinically important. It is recommended that treatment planning for patients with large breast size more carefully done.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
157
157
https://ijmp.mums.ac.ir/article_12659_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12659
Total skin electron therapy (TSET): Monte Carlo Simulation and implementation
Mitra
Ansari
Physics and Accelerators School, Nuclear Science and Technology Research Institute, AEOI, P.O. Box: 14155-1339, Tehran – Iran
author
Shahram
Monadi
Department of Radiotherapy, Seyedoshohada Hospital, P.O. Box: 8184917911, Isfahan, Iran
author
Hamid
Emami
Department of Radiotherapy and Oncology, School of Medicine, Isfahan University of Medical Sciences, P.O. Box: 8184917911, Isfahan, Iran
author
Farshad
Ghasemi
Physics and Accelerators School, Nuclear Science and Technology Research Institute, AEOI, P.O. Box: 14155-1339, Tehran – Iran
author
Ferydoon
Abbasi Davani
Radiation Application Department, Nuclear Engineering Faculty, Shahid Beheshti University, P.O. Box: 1983963113, Tehran- Iran
author
Mohhamad
Lamehi Rashti
Physics and Accelerators School, Nuclear Science and Technology Research Institute, AEOI, P.O. Box: 14155-1339, Tehran – Iran
author
text
article
2018
eng
Introduction: Total skin electron irradiation technique is used in treatment of the mycosis fungoid. The implementation of this technique requires non-standard measurements and complex dosimetry methods. Operating procedures for total skin electron irradiation and its dosimetry vary in different radiation therapy centers in the world. In this article, validation of TSET technique dosimetry data by Monte Carlo simulation is done.
Materials and Methods:
The electron beam characteristic of RTSEI for the only electron accelerator, located at the radiation center of the Seyed Alshohada Hospital of Isfahan (NEPTUN 10PC) determined by performing Monte Carlo simulations and using EGSnrc-based codes (BEAMnrc and DOSXYZnrc).
For the best uniformity of the vertical profile, the optimal angle of gantry was defined at SSD=300 cm. The effect of the degrader plane that is located at a distance of 20 cm from the patient surface, was evaluated on the amount of energy reduction of the beam, the opening of the electron beam field and the homogeneity of the dose distribution. The transversal dose distribution from the whole treatment with Rotational technique was simulated in a CT- based anthropomorphic phantom. Also, the percentage depth dose in the head, neck, thorax, abdomen and legs was obtained for RTSET technique.
TSET dosimetry requires measurements in nonreference conditions. Because of the complexity of the required measurements for the commissioning process of this technique, different dosimetric systems were employed such as radiochromic films (EBT3) and an ionization chamber. In particular, for dual-field beams irradiation, the optimal tilt angle was investigated and the dose distribution in the treatment plane was measured by radiochromic films. Dose distributions and percentage depth dose measurements for a total skin electron therapy were measured in an anthropomorphic phantom.
Results:
The optimal angle of 20o would give the most uniform total profile and the use of a 0.8 cm PMMA degrader in front of the patient leads to a homogeneous distribution of the dose in all directions (the mean relative dose value was 97%±5%, normalizing to 100% at the calibration point level). The percentage depth dose curves in different organs of anthropomorphic phantom for RTSEI indicates that the depth of maximum dose is on the surface of the phantom, Isodose curve of 80% is formed at a depth less than 4 mm and at the depth less than 1.5 mm, the dose decreases to 20% of the maximum dose.
Conclusion:
The main purpose of this study was to commission and optimize a TSET technique for the treatment of mycosis fungiodes with the NEPTUN 10PC linear accelerator. This was done through an extensive set of measurements and a large number of MC simulations. The results of Monte Carlo calculations were found to be in general agreement with the measurements, providing a promising tool for further studies of dose distribution calculations in TSEI.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
158
158
https://ijmp.mums.ac.ir/article_12661_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12661
The effect of incorporating the quantitative analysis besides visual assessments of 18F-FDG brain PET images for the localization of epileptogenic zones
Naghme
Firouzi
Department of Medical Physics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Parham
Geramifar
Research Center for Nuclear Medicine, Shariati Hospital, Tehran University of Medical Sciences , Tehran, Iran ,
author
Ali Asghar
Parach
Department of Medical Physics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
text
article
2018
eng
Introduction:
FDG Brain PET is a valuable paraclinical tool for presurgical assessments of patients suffering from refractory epilepsy. By the widespread accessibility of PET, recognizing the functional lesions has become a current practical method especially in preoperative evaluations of the partial epilepsy disorders. The aim of our study was to assess the impact of quantitative software-aided method in localizing epileptic zones in human brain using 18F-FDG Brain PET scan beside the physician qualitative interpretations.
Materials and Methods: The subjects have been selected among patients referred to brain PET imaging who were suffering from refractory epilepsy. Seventeen patients (9 men, 8 women
; 25±11 YO) underwent PET scan. Quantitative analysis of brain functional images were applied by the Scenium software which provided statistical color-coded images of Z-scores and standard deviations (1). We considered Z-scores<-2 as an abnormal range of brain metabolism. It is worth mentioning that, we categorized the patients based on their MRI investigations to lesional and non-lesional groups. Two physicians presented visual assessments in order to localizing epileptic spots. Also, the kappa index had been calculated as an agreement coefficient via SPSS (V.19.0) software.
Results: In the case of assessing the accordance of lesions’ localization among MRI, EEG, and PET/CT evaluations, the agreement level of EEG versus quantitative and qualitative method were reported 0.67 and 0.12, respectively, which were related to non-lesional group. Also, in the lesional category, the kappa indices for quantitative and qualitative analysis against the suspicious lesions on MRI were 0.56 and 0.27, respectively
Conclusion: Epilepsy disorder has destructive effects on quality of life. Thereby, accurate diagnosis of lesion locations could have a vital impact in order to patients’ treatment, exclusively in refractory epilepsy which might treat through doing the brain’s operation (2). The foregoing discussion is a confirmation of the supplementary role of quantitative software alongside visual assessments, in order to do pre-surgical evaluations of epileptic positions in human brain via 18F-FDG Brain PET images. Hence, utilizing of quantitative software could be a complementary method together with MRI and EEG procedures to improve the confidence of surgeon about the epileptic spots(3).
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
159
159
https://ijmp.mums.ac.ir/article_12662_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12662
Capacitive Hyperthermia as an Alternative to Brachytherapy in Treatment of Human Prostate Cancer Cell
Azam
Janati Esfahani
Department of Medical Biotechnology, School of Paramedical Sciences, Qazvin University of Medical Sciences, Iran.
author
Seied Rabi
Mahdavi
Radiation Biology Research Center, Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Samideh
Khoei
Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran
author
Mohsen
Bakhshandeh
Radiology & Radiotherapy department- Para Medical Faculty- Shahid Beheshti University of Medical sciences, Tehran, Iran.
author
Ali
Rajabi
Radiation Medicine Engineering Department, Shahid Beheshti University, Tehran, Iran
author
text
article
2018
eng
Introduction: The aim of this study was the evaluation of induced DNA damages of human prostate cancer cells, DU-145, treated with a combination of radiofrequency capacitive hyperthermia (HT) and teletherapy (EBRT) compared to a combination of teletherapy with high dose rate brachytherapy (BR).
Materials and Methods: DU-145 cells were cultured as spheroids in 300-micron diameter. Then the following treatments were conducted: a) EBRT at doses of either 2Gy or 4Gy of photon 15MV, b) HT for 30, 60, and 90 minutes’ duration at 43°C from a 13.56MHz radiofrequency capacitive heating device (Celsius TCS), c) BR with Ir-192 seed at doses of either 2Gy or 5.5Gy, d) The mentioned HT followed by EBRT (HT+EBRT) and e) EBRT followed by BR (EBRT+BR). Alkaline comet assay was performed to measure tail moment.
Results: The induced DNA damages of DU-145 cells treated by adding HT to EBRT compared with EBRT alone, showed a significant enhancement; 3.28 and 5.14 times respectively for 30 and 60 minutes HT. By plotting dose-response curves, we could find a range of doses, which create radiobiological iso-effect in HT+EBRT and EBRT+BR treatments.
Conclusion: This study suggests that about DNA damages of DU-145 cells, HT+EBRT could partly be considered as an alternative to EBRT+BR.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
160
160
https://ijmp.mums.ac.ir/article_12664_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12664
The evaluation of slant hole collimator in myocardial perfusion SPECT: a simulation study
Parvaneh
Darkhor
Department of medical physics, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Samira
Abbaspour
Department of radiotherapy, Arak University of Medical Sciences, Arak, Iran.
author
جلیل
پیرایش اسلامیان
Tabriz University of Medical Sciences
author
text
article
2018
eng
Introduction:
We have investigated cardiac SPECT with slant hole collimator in which the holes are slanted towards the target organ, to provide greater sensitivity over the parallel hole collimator. In addition, parallel hole collimator was used to obtain a comparison in FWHM, sensitivity, Compton and photoelectric area values in the simulations.
Materials and Methods:
A NaI: Tl crystal with a parallel and slant hole collimators were employed in the simulations. The collimator holes were slanted at a specific angle range of 0-30 degree. The NCAT phantom and a filtered-back projection algorithm was used for data generation and image reconstruction. The projection data acquired from the LAO position to provide lower attenuation to the heart. We also evaluated conventional MPS utilizing LEHR parallel hole collimator for the sake of comparison.
Results:
The evaluation of the reconstructed data showed that the FWHM for PH-SPECT ranged from
9.9 to 10.4 mm, while that for SH-SPECT ranged from 17 to 19 mm. The sensitivity values showed that conventional SPECT with 18.9 Cps/MBq, while that SH-SPECT provided higher sensitivity (18.93 to 25.21 Cps/MBq) compared with PH-SPECT. Furthermore, the Compton and photoelectric area in energy spectrum were 5.62 and 8.62%, 5.7 and 21.67% respectively for PH and SH SPECT.
Conclusion:
SH-SPECT is able to acquire higher sensitivity gain over the PH-SPECT.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
161
161
https://ijmp.mums.ac.ir/article_12666_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12666
Evaluation of Accuracy and Quality assurance of external beam therapy with photons
Vida
rezaee
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan Iran
author
Shahram
Monadi
Radiotherapy Section, Seyed Alshohada Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
author
text
article
2018
eng
Introduction: Receiving exact dose by the patients is vital in radiotherapy. In radiation therapy, the dosimetry of radiations is too important because of successful radiation inquires for delivering the exact dose to the target volume. This study is to evaluate the tolerances and the accuracy of calculated dose of photon beams in the treatment software system. The TECDOC1583 protocol is used to achieve this goal.
Materials and Methods: In this work, the Treatment Planning System TiGRT to distribute dose of photon beams was used and the measurements results in inhomogeneity phantom are compared in 4 levels.
Results: According to the TECDOC1583 protocl, the results are accepted but at third and fifth levels the error percent of lung and soft tissue were found to be 4.3%with a 0.3% difference and to be 5/7 with a 3% difference.
Conclusion: Because of the low density of electrons in the lung tissues, there were more errors in the planning system hence, the treatment planning needs more accuracy and the data should be reevaluated. Restarting the device and checking the dose values are recommended for applying the algorithms to get more successful treatment. We must be to solve the mistakes because it will effect so undesirable on the treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
162
162
https://ijmp.mums.ac.ir/article_12668_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12668
Radiosensitization effect of ZnO nanoparticles in lung cancer cells at clinically relevant megavoltage energy
Masoumeh
Zanganeh
Department of Medical Physics and Biomedical Engineering. School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
Hassan Ali
Nedaei
Department of Medical Physics and Biomedical Engineering. School of Medicine,
Radiotherapy Oncology Department, Cancer Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
author
Hossein
Mozdarani
Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Aziz
Mahmoudzadeh
Department of Biosciences and Biotechnology, Malek- Ashtar University of Technology, Tehran, Iran
author
text
article
2018
eng
Introduction: Radiation therapy is one of the major modalities that have long been used in cancer treatment. Radiotherapy is often accompanied by early and late toxicity and side effects and narrow therapeutic window. Similarity in radiation absorption properties of tumors and neighboring healthy tissues is often the reason for low specificity of radiation therapy. Development of nanomaterials for localized energy deposition under irradiation can increases radiation absorption by cancer tissue, expanding the therapeutic window and, thus, increasing specificity and efficacy of the treatment. ZnO nanoparticle is a wide band gap semiconductor with photo-oxidizing capacity under uv radiation. Recent studies have investigated photo-oxidizing under kilovoltage x-ray energy named as radiosensitization. The purpose of this study was to assess ZnO radiosensitization at clinically relevant MV X-ray energy.
Materials and Methods: ZnO nanoparticles with mean size of 10 nm were synthetized by a chemical precipitation method. The size, morphology and crystalline structure of the nanoparticles were characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. The cytotoxicity of ZnO nps was evaluated on SKLC-6 lung cancer cell line by cell proliferation assay. The effect of ZnO nps on cell radiosensitivity under 6MV energy x-ray irradiation was evaluated using colonogenic assay. Mode of cell death was evaluated by flow cytometry.
Results: TEM images showed spherical ZnO NPs with narrow size distributions were synthesized. XRD pattern of purely synthesized NPs exhibited seven reflection peaks that can be indexed to the ZnO wurtzite structure. ZnO NPs were cytotoxic to the SKLC-6 cells in a dose-dependent manner as cell viability was decrease with the increase concentrations of ZnO nps. When comparing the radiation effects between the nanoparticle-containing and nanoparticle-free samples, the calculated radiation enhancement ratio of about 1.35-fold was achieved.
FLow cytometry analysis confirmed that ZnO NPs, irradiation and combination of two induce apoptosis in SKLC-6 cells.
Conclusion: The potential of the ZnO nanoparticles for radiosensitization at MV energy was demonstrated in human lung cancer cell line (SKLC-6). Nanoparticle-mediated Enhancement Ratio was 1.35. Radiosensitizing effect can be attributed to X-ray-induced radiocatalysis by the nanoparticles at MV energy. Further development of ZnO nps might provide a new useful tool for research and clinical therapy in the field of oncology.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
163
163
https://ijmp.mums.ac.ir/article_12669_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12669
Total Antioxidant Capacity level in Radiation Workers and other Staffs of Hospital in Sistan and Baluchestan Province
Jalal
Ordoni
MSC of Radiobiology, Department of Radiology, Faculty Member of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran.
author
Vida
Sargazi
MSC of Medical Physic, Department of Radiology, Faculty Member of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran
author
Zeinab Yazdi
Stoodeh
MSC of Medical Imaging, Department of Radiology, Faculty Member of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran
author
Yazdan
Salimi
MSC of Medical Physic, Department of Biomedical Engineering and Medical Physics, Faculty of medicine, Shahid Beheshti University of Medical Science, Tehran, Iran
author
Dariush
Askari
MSC of Radiobiology, Department of Radiology, Faculty of Paramedicine, Shahid Beheshti University of Medical Science, Tehran, Iran
author
text
article
2018
eng
Introduction: Human’s body and other creatures fight with destructive factors, as well as other factors that threaten human health and life. There is an antioxidant biological system in living organisms to face oxidizing compounds. In this immune system, compounds are found that react directly with oxidizing agents and make them neutral. The variety of compounds are included compounds with low molecular weight antioxidants such as vitamins E, C. For any reason that serum or intracellular antioxidants decreases, oxidizing substances that released and remain active can damage cell. To assay the total antioxidant capacity (TAC) of radiation workers serum in diagnostic radiology centers of Zahedan city in I.R.Iran.
Materials and Methods: This case-control study was conducted by 41 case radiation workers and 81 controls between June 2016 and February 2017, in biochemistry Laboratory of Zahedan university of medical science. Case persons were taken from radiation workers who didn’t go vacation in the past month and control from staffs of other parts of centers with the least probability of man-made radiation exposure. Case-control arms matched in age, gender and economic situation. Then 5 ml whole blood was taken from each of them. For measurement TAC of serum, we used FRAP assay (Ferric Reducing Ability of Plasma). p values
<0.05 were considered as statistically significant.
Results: Mean capacities of antioxidant were 801.3 and 879.89 µmol/L for control and case groups respectively. It was not statistically significant (p = 0.062). There was statistically significant relation with gender (p = 0.021, F = 0.96). Average level was measured 941.21 ±
149.10 and 826.95 ± 93.96 µmol/L for men and women respectively.
Conclusion: It seems that antioxidant systems are effective in deactivating produced free radicals. It can be concluded exposure to radiation was not amount to have significant effect on TAC of persons in this study. It matched data extracted from film badge dose meters. Antioxidant level was higher in men than women, because of higher uric acid of serum
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
164
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https://ijmp.mums.ac.ir/article_12670_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12670
Assessment of diagnostic value of DWI technique in the evaluation of liver fibrosis
Jalal
Ordoni
MSC of Radiobiology, Department of Radiology, Faculty Member of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran
author
Zeinab
Yazdi Stoodeh
MSC of Medical Imaging, Department of Radiology, Faculty Member of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran
author
Vida
Sargazi
MSC of Medical Physic, Department of Radiology, Faculty Member of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran
author
Dariush
Askari
MSC of Radiobiology, Department of Radiology, Faculty of Paramedicine, Shahid Beheshti University of Medical Science, Tehran, Iran
author
Yazdan
Salimi
MSC of Medical Physic, Department of Biomedical Engineering and Medical Physics, Faculty of medicine, Shahid Beheshti University of Medical Science, Tehran, Iran
author
text
article
2018
eng
Introduction: The liver fibrosis is caused by extracellular accumulation of cluster, glycos amino glycans and proteoglycans, which this extracellular accumulation may limit the penetration and molecular movement of water in the tissue, so the Diffusion weighted imaging(DWI) technique is due to the sensitivity to the movement and release of water molecules Can show this restriction. Using this technique, in addition to examining the entire liver, sections of the liver tissue most affected by fibrosis can also be identified. The purpose of this study was to evaluate the use of apparent diffusion coefficient (ADC) measurement in DWI imaging technique and to investigate the correlation between this method and the method of sampling in patients.
Materials and Methods: Twenty-five chronic viral hepatitis C patients were examined by 1.5 Tesla MR scanner with diffusion gradient encoding in three orthogonal directions at b-values of (200, 500, 700, and 1000 s/mm2). They were correlated to biopsy finding and graded according to Ishak scoring system. Hepatic ADC values were measured for patients.
Results: The best correlation between ADC values and biopsy were seen at b-values 200, 700, and 1000 s/mm2. lesser correlation was obtained at b-values of 500 s/mm2. Cut off values between different grades of fibrosis were calculated and presented in the text.
Conclusion: ADC measured with DWI is a reliable non-invasive technique for quantification of liver fibrosis, and could replace liver biopsy in certain cases.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
165
165
https://ijmp.mums.ac.ir/article_12671_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12671
The effect of two different polymeric-coated magnetite nano-graphene oxide as 5-fluorouracil carrier and radiofrequency hyperthermia on colon cancer in vitro
Leila
Kiamohamadi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, IRAN
author
Samideh
Khoei
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, IRAN
Razi Drug Research Centre, Iran University of Medical Sciences, Tehran, IRAN
author
Sepideh
Khoee
Department of Polymer Chemistry, School of Sciences, University of Tehran, Tehran, IRAN
author
Leili
Asadi
Department of Plasma Physics, Islamic Azad University Science and Research Branch, Tehran, IRAN
author
text
article
2018
eng
Introduction: Colon carcinoma is one of the most common form of cancer that affects the health and lives of people. 5-Fluorouracil (5-Fu) has become useful as synergistically therapy with other antitumor agents in a colon cancer therapy. Short half-life, wide distribution and different side effects of 5-Fu limit its medical applicability. In this study, we have investigated the drug release and the requisite time of hyperthermia of PCL-Chitosan coated magnetite nano-graphene oxide (SPION-NGO-PCL-Chitosan) and PLGA-coated magnetite nano- graphene oxide core (SPION-NGO-PLGA) as carriers of 5-Fu on CT26 colon cancer cells.
Materials and Methods: The in vitro 5-Fu release from nanoparticles was performed by the diffusion method. A weighed amount of nanoparticle was suspended in PBS and next transferred into a dialysis bag. The bag was placed into 12mL PBS at different temperature conditions (37 and 43°C) under pH=7.4 as a release medium. The released 5-Fu concentration was measured using a UV visible spectrophotometer analysis at 265 nm.
In order to obtain the requisite time of radiofrequency hyperthermia using AMF at 43oC, 5×105 CT26 cells were seeded in T-25 flasks. After 24 hours, the cells were treated with
50.24 μg/mL of 5-FU-SPION-NGO-PLGA or 14.4 μg/mL 5-Fu-SPION-NGO-PCL-Chitosan nanoparticles (equivalent to about 1 μΜ of 5-Fu) for 24 hours. After 24h, the cells were washed twice with PBS and the culture medium was replaced with a fresh medium. Finally, the cells were irradiated with the alternative magnetic field (power of 50 W) (Basafan, Iran). Moreover, control samples without NPs treatment were prepared and irradiated with AMF. Temperature variations of the cells were evaluated with a digital infrared (IR) thermal camera (Testo 875-1i, Germany) during AMF irradiation.
Results: The results show that 5-Fu was released from PLGA-coated NPs and PCL-chitosan- coated NPs to the extent of 41.36% and 75.84% within approximately 24 h at 37oC, respectively. Total release from 5-Fu-SPION-NGOPLGA and 5-Fu-SPION-NGO-PCL-Chitosan at 37oC over 7 days was 57% and 81%, respectively. The 5-Fu release within 4h was equivalent to 71% for PLGA-coated NPs and 97% for PCL-chitosan-coated NPs at 43°C. To evaluate the requisite time of hyperthermia at 43oC, treated flasks with nanoparticles were irradiated with AMF and monitored with IR camera. Finally, As observed, the increasing temperature profiles of the cells as a function of time. The mean temperature of the cells irradiated to AMF
was increased to 43°C at 17, 6 and 5 minutes for control, SPION-NGO-PCL-chitosan, and SPION-NGO-PLGA groups, respectively.
Conclusion: According to this study, SPION-NGO-PCL-chitosan NP and SPION-NGO-PLGA NP as 5-Fluorouracil carriers and AMF hyperthermia increased the effect of the hyperthermia which lead to lower dosages of drugs that could induce harmful side effects.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
166
166
https://ijmp.mums.ac.ir/article_12672_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12672
Investigation of physical penumbra definition in IMRT applications
Hajar
Alipour
Department of Nuclear Engineering, Shiraz University, Faculty of Mechanical Engineering, Email: halipour@shirazu.ac.ir Tel: +98 9385741949
author
Kamal
Hadad
1Department of Nuclear Engineering, Shiraz University, Faculty of Mechanical Engineering,
author
Reza
Faghihi
Department of Nuclear Engineering, Shiraz University, Faculty of Mechanical Engineering,
author
text
article
2018
eng
Introduction:
Because of small size of the beamlets in IMRT, physical penumbra is one of the important dosimetric parameters and small changes in the penumbra will have a great impact on the results. The physical penumbra width is defined as the lateral distance between two specified isodose curves at a specified depth of phantom. In this study, after demonstrating the inconsistency of conventional physical penumbra definition for non-uniform MLC fields, two new dosimetric parameters proposed, those are intended to be suitable for MLC fields
Materials and Methods: Physical penumbra evaluation was obtained using IAEA phase space data for a Varian IX and EGSnrc Monte Carlo code package. The homogenous water phantom is located at SSD=100 cm.
Results: With conventional definition, physical penumbra widths for all MLC setups on right and left sides of isodose curves (parallel to X and Y axes) are not equal. With the proposed dosimetric parameters, the effect of MLC setup is taken into consideration.
Conclusion: The intended purpose from physical penumbra in its conventional definition is not satisfied for non-uniform MLC setups. For such cases, the newly defined surface penumbra and uniformity index are demonstrated to be more suitable and indicative of the field non-uniformity. It is also shown that for an idle treatment planning system, the uniformity index approaches unity.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
167
167
https://ijmp.mums.ac.ir/article_12674_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12674
Synergistic effects of Radiofrequency Hyperthermia temperature rate with magnetic Graphene oxide nanoparticles drug targeting on CT26 colon cancer cell line
Leili
Asadi
Department of Plasma Physics, Islamic Azad University Science and Research Branch, Tehran, IRAN
author
Samideh
Khoei
Razi Drug Research Centre, Iran University of Medical Sciences, Tehran, IRAN
author
Sepideh
Khoee
Department of Polymer Chemistry, School of Sciences, University of Tehran, Tehran, IRAN
author
Leila
Kiamohammadi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, IRAN
author
text
article
2018
eng
Introduction:
Graphene oxide (GO) sheets are carbon-networking nanomaterials offering excellent
potential for drug delivery platforms due to hydrophobic interactions and high drug-loading efficiency. Superparamagnetic iron oxide nanoparticles can be used in certain applications such as cell labeling, drug delivery, targeting, magnetic resonance imaging and hyperthermia. Due to the larger surface to volume ratio for unmodified iron oxide nanoparticles, they usually possess high surface energy leading to particle aggregation. The magnetic nanoparticles could induce heat energy in an alternating magnetic field (AMF). The
absorption of radiofrequency energy by biological tissue results in higher tissue
temperatures as a function of time, which eventually causes cell death due to hyperthermia.
Mensuration of the temperatures inside the tumors and in normal tissues within AMF
demonstrated that this treatment could induce tumor-specific hyperthermia.
Materials and Methods:
CT26 colon cancer cell line was cultured in vitro as a monolayer. The monolayer culture was
treated with of 5-FU, 5-FU- MGO nanoparticles, and MGO nanoparticles for 24 hours. then
the flasks were located at the centre of the RF coil where the alternative magnetic field
strength had reached its maximum value (40 kA/m) and was exposed to the AMF (forward
power, 70 W), for 12 min (43°C) without MGO nanoparticles and 4 min (43°C) with MGO
nanoparticles. During the AMF exposure, the temperature increase was monitored using a
T-type thermocouple (copperconstantan, 0.1 mm diameter) linked to a digital thermometer
(Lutron thermometer TM-917, Taiwan) every 1 min for 15 min with ± 0.1°C accuracy.
Results:
Increase in the temperature was measured. The results revealed that the temperature
increase of the culture depends on the nanoparticles concentrations. The results also
indicated that the temperature of cells exposed to AMF (13.56 MHz) at a forward power of
70 W reached to 43°C after 12 min, whereas the combination of accumulated 50 μg/ml 5-FU-
MGO nanoparticles and RF hyperthermia was 3 min and for 25 and 5 μg/ml, it was calculated
as 4 and 9 min, respectively. The significant difference was observed between the 5-FU, 5-
FU- MGO nanoparticles, and MGO nanoparticles in RF hyperthermia at power of 70 W (P <
0.05). This suggests that MGO nanoparticles act as effective thermal agents in AMF
hyperthermia.
Conclusion:
On the basis of this study is According to the temperature-time curves at different intensities,
the rate of temperature rise was very sharp during the first few minutes of AMF exposure;
however, it then reached a near equilibrium because cell heat transfer parameters
(conduction and convection) started to perform, The radiofrequency heats cells with a steep
gradient pending the initial stage of exposure.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
168
168
https://ijmp.mums.ac.ir/article_12675_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12675
Developing a mobile application for usual calculations of radiotherapy physics
Gholamreza
Ataei
MSC of Medical Physics, Department of Radiation Physics, Faculty of Paramedical, Babol University of Medical Sciences, Babol, Iran
author
Saman
Cham
BSc Student of Research Committee, Babol University of Medical Sciences, Babol, Iran
author
Ali
Shabestani Monfared
Department of Medical Physics & Radiation Biology, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Fatemeh
Niksirat
MSc of Medical Physics Radiobiology and Radiation Protection Department, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Kourosh
Ebrahimnejad Gorji
PHD of Medical Physics, Department of Medical Physics Radiobiology and Radiation Protection, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
text
article
2018
eng
Introduction:
Successful radiotherapy requires the precise application of a radiation dose to cancerous tissue, which can be achieved by the design of proper treatment methods by radiotherapy physicists. Tasks performed by radiotherapy physicists include verifying the accuracy of dose calculations, correct treatment planning and the proper functioning of accelerators. They are also responsible for controlling the radiation dose applied to tumors and sensitive organs. Because more than half of cancer patients need radiotherapy, the related calculations are very important in the estimation of the tumor dose. Owing to the increased use of computers and simulation software in medical science, as well as trends indicating its continued growth. This study aims to develop a new smart-phone application to perform common radiotherapy-related calculations.
Materials and Methods:
The proposed application was developed using several resources including radiotherapy physics reference books based on the Android operating system in Java. The items that were applied in this application for the calculation process include: superficial dosimetry, cobalt dosimetry (water phantom), cobalt dosimetry (in air), timer error, time dose fractionation (TDF), superficial cone, superficial collimator, equivalent square, Linac dose, tissue phantom ratio 20-10, motorized wedge, field gap, biologically effective dose (BED), absolute linac dosimetry, Mayneord F factor. The last eight items mentioned above are available in separate categories within the application. Each category has the following headings: “Item”, “Help”, “Related citations”, and the “Last review” of the application developer in the latest version of the cited source. Explanations and details of all mentioned formulas and calculations are available in the cited sources. The results can be saved after completing the process of calculating the factor of the item.
Results:
All programming and computational errors were resolved using Android Studio software. It was observed that this application can perform mathematical computations without errors to several decimal places. The application runs on all smart-phones with android version 4 and up. So far, the application has been investigated and approved manually by the radiotherapy physicist and application developer programmer, according to the latest sources of oncology and radiotherapy physics listed in the Materials and Methods.
Conclusion:
Given that there are no existing mobile applications in this field, the proposed application may be useful in facilitating and accelerating radiotherapy related calculations.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
169
169
https://ijmp.mums.ac.ir/article_12676_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12676
Comparing experimental assessment of the peripheral dose outside the applicator in electron beams of ELEKTA with Treatment planning system
Abbas
Haghparast
Medical Physics Department, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Fatemeh
Amiri
Radiology Department, Faculty of Paramedicine, Kermanshah University of Medical Sciences, Kermanshah, Iran. . Phone: +98 8334274623 E-mail: fatemehamiri22@yahoo.com
author
Mehran
Yarahmadi
Medical Physics Department, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Mohammad
Rezaei
Biomedical Engineering Department, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: The use of electrons in the electron therapy to destroy tumoral tissue is dedicated significant contribution of different methods of radiation therapy. Scattered radiation due to exited electrons of the applicator affect the dose out of the field in the patient's normal tissue. The aim of this study is to determine the peripheral dose outside the applicator in the electron beams of Elekta accelerator.
Materials and Methods: In this study the peripheral dose outside the applicator in electron beams was measured using linear accelerator Elekta Synergy Plateform and it was compared with the obtained results from the treatment planning system (TPS) Isogray model. The peripheral dose profiles were measured and compared Using the solid water phantom set and the film dosimetry system of EBT3 at energy levels 6, 10 and 18 MeV in the applicators with the different dimensions and at different angles of 0, 10 and 20 at the depth 0 and 0.5 and 1cm and for each energy level at depth of maximum dose (Dmax). The peripheral dose Profiles has been normalized to the edge of the field.
Results: The highest Peak dose was observed in 18 MeV beam outside the applicator. Peak dose was reduced with increasing the electron beam energy. Using the applicator 20 × 20 cm2 for energy 18 MeV, a dose peak of 1.6% was observed on the surface at a distance of 2 cm from the outer edge of applicator and also for energy 6 MeV, 1.15% at the same distance from the edge of the applicator. It was found that the dose peak decreases with increasing depth and increases with increasing field size. Also the dose peak increased with increasing gantry angle from zero to 20 degrees. The result of measured peripheral dose outside the applicator by using TPS of Clarkson algorithm showed that the dose Calculation can be evaluated only up to distance of 3cm from the edge of the field.
Conclusion: Totally, anticipation of dose distribution of the electron beams in collision with matter is different and difficult in various accelerators because of the complexity of the behavior of electrons. However, according to the results of this study in Elekta accelerator, noticeably dose peak was observed in use of high-energy electron beams because of more incidence of bremsstrahlung radiation outside the treatment field. The radiotherapy team can have prevented from damage to organs at risk outside the applicator by awareness of the value and location of peripheral dose outside the treatment field with applying the principles of radiation protection like shields. The evaluated TPS is not a good way to measure the peripheral dose outside the field.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
170
170
https://ijmp.mums.ac.ir/article_12677_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12677
The plastic tray effect on the spectrum of photoneutrons prudused by 18 MV medical linac using the Monte Carlo method
Seyed Mehdi
Hashemi Dizaji
Radiation Application Research School, Tehran, Iran.Tel: 026 34464058. E-mail: mehdihashemmi@yahoo.com
author
text
article
2018
eng
Introduction: One of the important problems of using high energy linacs is the production of photoneutrons. High energy medical linacs produce secondary neutrons. These phtoneutrons increase patient dose
Materials and Methods: In this study, the effect of plastic trays on spectrum of photoneutrons produced by 18MV linac is investigated using the MCNP4C code. To determine the photoneutron spectrum a simplified linac head simulated. In order to contribute the all components of the spectra, an isotropic neutron source was considered with an energy spectrum derived from the relevant equation. Source defined at the center of a thick walled sphere of tungsten. Two kinds of trays, PMMA and Polyethylene, each with 1.5 cm thickness defined just under the aperture of simplified linac head. A typical treatment room simulated with the walls made of standard concrete. Neutron detectors defined as spheres of 10 cm diameter. One of the detectors defined just under the linac head and the other at the adjacent of the bucker door. Three situations were considered, one without tray and two others with trays. Simulation carried out by running the computer to produce 100 millions of particles for each case. F4 tally was used.
Results: The results show that spectrum of photoneutrons differs considerably for open field and shielded fields.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
171
171
https://ijmp.mums.ac.ir/article_12678_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12678
Computerize classification of Benign and malignant thyroid nodules by ultrasound imaging
Akbar
Gharbali
Medical Physics Department, Faculty of Medicine, Urmia Medical science University
author
text
article
2018
eng
Introduction: Early detection and treatment of thyroid nodules increase the cure rate and provide optimal treatment. Ultrasound is the chosen imaging technique for assessment of thyroid nodules. Confirmation of the diagnosis usually demands repeated fine needle aspiration biopsy (FNAB). So, current management, has morbidity and non zero mortality. The goal of the present study is to explore diagnostic potential of automatic texture analysis (TA) methods in differentiation benign and malignant thyroid nodules by ultrasound imaging in order to help for reliable diagnosis and monitoring of the thyroid nodules with no need more biopsy.
Materials and Methods: The database consist of 70 thyroid patients (26 benign and 44 malignant). They under- went thyroid sonography which were reported by radiologist and proven by the biopsy. One ultrasound image per patient was loaded in Mazda Software version 4.6 for automatic texture analysis. Regions of interests (ROIs) were defined within the abnormal part of the thyroid nodules ultrasound images. Gray levels intensity within a ROIs normalized and then up to 270 multi scale texture features parameters per ROIs per normalization schemes were computed via statistical methods employed in Mazda software. From the statistical point of view, all calculated texture features parameters are not useful for texture analysis. So, the features based on F: maximum Fisher coefficient and P: minimum probability of classification error and average correlation coefficients (POE+ACC) eliminated to 10 best and most effective features per normalization schemes. We analyze this feature under two standardization states standard (S) and nonstandard (nS) with Linear Discriminate Analysis (LDA) and None Linear Discriminate Analysis (NDA). The first nearest neighbor (1NN) and artificial neural network (A-NN) classifier were performed for features obtained via LDA and NDA respectively to differential diagnosis benign versus malignant thyroid nodules. The confusion matrix applied between visual and automated texture analysis results to find out sensitivity and specificity of the applied texture analysis methods under different applied options. The Receiver operating characteristic (ROC) curve analysis used for comparison discrimination performance of the employed texture analysis methods.Results: The results demonstrated the influence of the normalization, reduction and standardization on the effectiveness of the obtained features in discrimination tasks by LDA and NDA texture analysis.In comparison with LDA, The selected subset features represent the highest discrimination performance for NDA in distinguishing benign from malignant thyroid with sensitivity of 94%, specificity of 100%, and Az value of 0.97. It means that via our method 97% patient with thyroid nodules lesions can be diagnostic without doing clinical biopsy. For LDA, this discrimination result has sensitivity of 85.7%, specificity of 87.5%, and Az value of 0.86.Conclusion: Our results indicate Computer aided diagnosis can provide useful information to help radiologists in classification of benign and malignant thyroid nodules.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
172
172
https://ijmp.mums.ac.ir/article_12680_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12680
Evaluation of combination effects of radiotherapy, hyperthermia and curcumin on glioma spheroids
Bita
Ghanbari
aa
author
text
article
2018
eng
Glioblastoma is most common and most aggressive cancer of brain. for treatment surgery is first selection and radiation therapy then chemotherapy. The median survival of Patients with GBM is less than a year after diagnosis. Glioblastoma is basically resistant to common cancer treatments. today to improve the response of patients to treatment, a number of strategies such as the use of radiation sensitizer and combination therapy is recommended, in this study we have applied combination of radiation therapy, hyperthermia and curcumin a verbal radiosensitizer to increase glioblastoma treatment
purpose: showing combination effects of three treatments chemotherapy by curcumin, radiation therapy and thermotherapy or hyperthermia on spheroid cells of human glioblastoma, their injuries were evaluated by RT PCR and MTT assay.
Material and methods: spheroids with100μm diameter were treated by radiation, curcumin and hyperthermia, then the viability assessed by MTT assay, level of Bax and Bcl-2 expression was measured by RT PCR
Result: in MTT assay viability decreased after all treatments, RT PCR confirmed MTT assay results: after all treatments Bax expression increased and Bcl-2 decreased. dcreasing in MTT assay and Bcl-2 expression and increasing in Bax expression was respectively: the group treated with hyperthermia, curcumin, radiation, hyperthermia-radiation, curcumin- radiation, curcumin-hyperthermia and curcumin-hyperthermia-radiation
Discussion: glioblastoma is resistant to treat due to decrease apoptosis, in other side radiation, curcumin and hyperthermia induce apoptosis, also hyperthermia prevents of sublethal damages repair of radiation, curcumin beside increasing apoptosis makes G2/M and G1 arrest so it can promote radiation and hyperthermia effects on cell death. finally we can compensate modalities faults by combination therapy and intensify cell death and treatment performance.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
173
173
https://ijmp.mums.ac.ir/article_12681_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12681
Investigation of lung normal tissue doses in lung tumors radiation therapy using both gated and conventional radiotherapy
Sara
Shahzadeh
Department of Nuclear and Medical Radiation Engineering, Shahid Beheshti University, Tehran, Iran.
author
Somayeh
Gholami
Radiotherapy Oncology and Radiobiology Research Centre, Cancer institute, Tehran University of Medical Sciences, Tehran, Iran
author
Seyed Mahmood Reza
Aghamiri
Department of Nuclear and Medical Radiation Engineering, Shahid Beheshti University, Tehran, Iran.
author
Hojjat
Mahani
Radiation Application Research School, Nuclear Science and Technology Research Institue, Tehran, Iran
author
Mansoureh
Nabavi
Radiotherapy Oncology and Radiobiology Research Centre, Cancer institute, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: In radiation therapy of lung tumors, respiratory motion causes target moving, so a larger margin is needed to cover the clinical target volume (CTV). With the margin increasing, a larger volume of normal tissue will be exposed to high-dose. In this study, dosimetric parameters of normal lung tissue were compared between gated and conventional radiotherapy (RT), using the NCAT digital phantom.
Materials and Methods: Different series of CT images of sample patients were created, using the NCAT digital phantom and MATLAB software. Lesions with diameters of 3, 4 and 5cm were located in different positions of lung (left upper and lower lobes, right upper and lower lobes) in the CT images. Appropriate margins were applied to the CTVs depending on the radiation therapy technique and respiratory cycles. To evaluate the effect of diaphragm extension on the margins to CTV, different diaphragm motions were considered from 2 to
3.5 cm with 0.5 cm intervals. PCRT treatment planning system with Superposition computational algorithm was used to deliver a dose of 60Gy in 30 fractions to the PTVs. Totally, 36 treatment plans were evaluated for each RT technique and Mean lung dos (MLD) and V20 were calculated for both conventional and gated RT techniques.
Results: A significant impact on MLD and V20 reduction was seen in lung normal tissue in gated RT up to 5Gy and 37%, respectively.
Conclusion: In all cases, gated RT has a superior advantage compared to conventional RT, especially for the lesions that are near to the diaphragm.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
174
174
https://ijmp.mums.ac.ir/article_12682_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12682
Estimation of Mean Estimation of Mean Glandular Dose in Mammography Examination in some of Radiology Centers in Tehran city
Shadzi
Fakhri Tari
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran.
author
Fathollah
Buzarjomehri
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran.
author
Mehdi
Salehi Barough
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran.
author
text
article
2018
eng
Introduction: the objectives of this research were determination of Mean Glandular Dose in film- screen and digital mammography examinations, estimation of accumulated effective dose in some of mammography centers in Tehran city and estimating cancer risk due to these examinations.
Materials and Methods: the clinical data were collected from the 1318 mammograms taken from 333 women who were referred to 4 mammography centers in Tehran. The mammography instruments in this study were one film-screen system, one DDR system and two CR system. An RTI dosimeter, piranha system version 3.1, was used for measurement of ESAK and HVL. Compressed breast thickness determined by the mammography systems which was calibrated by a millimeteric ruler. Dgn conversion factor was determined from a program written in C by Bouzarjomehri and et al. Height and weight patients were also measured.
Results: The mean ±SD results of MGD per film and per woman were respectively 2.04±0.75 mGy and 8.12 ± 2.75 mGy. The mean effective dose ± SD of patient was 0.4±0.13 m Sv. the number of patients referring to these four mammography centers estimated 8352 per year, so accumulated dose was 3.34 ±1.08 man. Sv
With considering of 8% per Sv cancer risk, according to BEIR VII report, the carcinogenic risk of the mammography examinations in these centers will be 0.26 women per year.
The MGD results showed a relatively linear correlation with CBT, but age, weight, BMI of the patients haven’t a correlation with MGD, r2<0.3.
Conclusion: The average MGD per mammogram of this study was higher than other references, which may be due to the higher average breast thickness of these women relative of the other references but the mean MGD of this study was lower than the RLs values reported by ICRP (3 mGy). The average MGD resulted in this study for the analogue mammography device was lower than the computed radiography (CR) and the direct digital radiography (DDR) devices of.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
175
175
https://ijmp.mums.ac.ir/article_12683_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12683
Monte Carlo Simulation of Prostate Intensity Modulated Radiotherapy Using PRIMO Software: A Feasibility Study
Mohammad Javad
Khosravanipour
Department of medical physics, faculty of medical science, Tarbiat modares University, Tehran, Iran. Email: m.khosravanipour@modares.ac.ir
author
min
Banaei
Department of medical physics, faculty of medical science, Tarbiat modares University, Tehran, Iran. Email: amin.banaii@modares.ac.ir
author
text
article
2018
eng
Introduction: Nowadays Intensity Modulated Radiotherapy (IMRT) is a common method for treating prostate cancers. Must of the Monte Carlo software cannot simulate the IMRT procedures due to inability of these soft wares to simulate the multi leaf collimator (MLC) positions or movements. A new user-friendly software based on the PENELOPE Monte Carlo code named PRIMO was published recently. This software can simulate the MLC positions in IMRT procedures. The aim of this study was to simulate the prostate IMRT fields and calculate the dose on a physical phantom.
Materials and Methods: PRIMO software was used to simulate the Varian clinic 600c and Varian 80L MLC. The MLC movement was simulated in PRIMO using control points that can be obtained from the treatment planning software (TPS). A CT scans of Delta 4 phantom (ScandiDos, Sweden) were imported to the PRIMO and typical 9 fields IMRT planning was simulated on this phantom. Empirical measurements were done using Delta 4 phantom with its inside embedded diode dosimeters and computer software. Dose comparison between the simulation and empirical measurement was done using gamma evaluation method (2%, 2mm) in PRIMO software module.
Results: Simulated results were in good agreement with measurement. 99% of gamma points were lower than 1. Anterior, lateral and anterior oblique fields were in complete agreement with simulation, i.e. 100% of gamma points <1. Posterior and posterior oblique fields had a few gamma points >1.
Conclusion: PRIMO software can precisely simulate the prostate IMRT in relevant clinical accessible time. The difference between simulation and measurement in posterior fields may be due to the treatment couch that was not simulated in PRIMO.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
176
176
https://ijmp.mums.ac.ir/article_12788_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12788
Gamma-ray shielding properties for silicate glasses containing Bi2O3, PbO, and BaO
Reza
Bagheri
Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran, Postal code: 14395-836.
author
Alireza
Khorrami Moghaddam
Radiology Department, Paramedical Faculty, Mazandaran University of Medical Sciences, Sari, Iran, Postal code: 14536- 33143.
author
Seyed Pezhman
Shirmardi
Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran, Postal code: 14395-836.
author
text
article
2018
eng
Introduction: With the extensive application of radiation sources and radioactive materials in various fields, the study of attenuation and absorption of X-rays and gamma-rays in several materials has become an essential and interesting field of research. Glass materials are possible alternatives of concretes for radiation-shielding materials.
Materials and Methods: The mass attenuation coefficients (µm), effective atomic cross section (σa), effective atomic number (Zeff) and effective electron density (Neff) of silicate glasses containing different concentrations of Bi2O3, PbO, and BaO (30–70% by weight) were obtained using MCNP-4C code, XCOM and XMuDat programs, in the energy range of 10 keV–10 MeV. The interpolation method was employed to extract Zeff and Neff. The Auto-Zeff software was used to determine the Zeff as well.
Results: The MCNP-4C Code, XCOM and XMuDat programs and Auto-Zeff results were in good agreement. It was found that the µm and σa values decrease with photon energy. Also the results indicate that σa and Zeff of glasses improve by increasing their Bi2O3, PbO and BaO contents, while increasing these contents to the same fraction has no significant effect on µm in the energy range of 0.3–5 MeV, where the Compton Effect takes over as dominant process and Neff do not follow certain rule. Above 0.1 MeV, lead oxide silicate glass showed the highest values of Zeff and σa.
Conclusion:
Observed good agreement indicates that the chosen Monte Carlo code and computer programs may be useful to calculate the gamma-ray shielding characteristics of different glass systems, particularly in cases where no experimental data exist.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
177
177
https://ijmp.mums.ac.ir/article_12789_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12789
Dosimetry of Nano-Radio-Ytterbium Therapy by MIRD and MCNP methods for humans’ organs
Leila
Moghaddam-Banaem
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran. ), Tel: +98-21-82062382.,
author
Navideh
Aghaei-Amirkhizi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran. ), Tel: +98-21-82062382.,
author
Sodeh
Sadjadi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran. ), Tel: +98-21-82062382.,
author
Fariba
Johari- Daha
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran. ), Tel: +98-21-82062382.,
author
text
article
2018
eng
Introduction: Nano radio-pharmaceutical therapy (NRPT) is a new method for solid tumor therapy. The treatment uses a radioactive form of radionuclide encapsulated in the poly amido amine dendrimers. The poly (amidoamine) (PAMAM) dendrimers have attracted attentions for cancer treatment by their characteristics of targeted drug carriers, delivery agents, and imaging agents in human systems.
We have reported the preparation of dendrimer encapsulated ytterbium-175 radio- nanoparticles and its biodistribution in tumor bearing rats.175Yb (T1/2=4.2 days), decays to stable 175Lu with a β- emitter with 470 keV maximum energy (86.5%) and γ photons of 113 keV (1.9%), 282keV (3.1%) and 396 keV (6.5%) that are appropriate for imaging. This paper aims at comparing dosimetric assessments in human performed with Monte Carlo codes and MIRD based on the experimental results of biodistribution of dendrimer encapsulated ytterbium-175.Materials and Methods: All chemical materials including, Ytterbium (III) oxide (Yb2O3), PAMAMG5-NH2 dendrimer in 5% methanol solution and HNO3, Sodium boro- hydride (NaBH4) were purchased from Sigma Aldrich Chemical Co. USA and Merck, Germany.
For biodistribution study 20 female Balb/c mice were purchased from Pasteur Institute of Iran. To estimate the absorbed dose by both methods, MCNP and MIRD, the cumulated activity in source organs were calculated by the percentage of injected dose in humans’ organs. The residence times (τ) in the source organs were obtained by integration of respective fit functions, on biokinetics curve, after accounting for the physical decay of the 175Yb. The dose calculation was done for a certain group of organs of human following the MIRD technique.
To simulate the problem with MCNP, the ORNL phantom was used. The desired result for this study is absorbed doses of vital organs (liver, spleen, lung and kidney).
Results: The maximum uptake of radio-compound are in the liver, lung and spleen. The biodistribution shows the characteristics of nanoparticles such as size and surface hydrophobicity that determine the amount of adsorbed radiopharmaceuticals in organs. The initial fast distribution of radiotracer is throughout liver, lung, and Bone, with slower accumulation in blood and spleen. The result of 2 methods (MIRD versus MCNPX) reveals that MIRD underestimate the absorbed dose for bladder, bone, lung, and ovaries while overestimate for liver, muscle and spleen. In this study the absorbed dose from 175Yb- PAMAM estimated by MCNPX for liver, lung, spleen, kidney and bone are 1.266, 8.081E-01, 8.347E-01, 3.979E-02 and 1.706E-02 mGy/MBq respectively
Conclusion: Owing to the stability of PAMAM encapsulated Yb-175 and the size of nano- particle the concentrations are mostly in liver and lungs. State of- the-art dosimetry depends on the duration of the biokinetics of the radiopharmaceutical and a calculation of residence times including an analysis of the errors associated with the respective calculation that aimed in this study. The results showed that this nano-radiopharmaceutical has potential of application for liver and lung tumors.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
178
178
https://ijmp.mums.ac.ir/article_12790_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12790
Texture analysis of the ovarian lesions by CT scan images
Akbar
Gharbali
Assistant professor of Medical Physics, Department of Medical Physics, Faculty of Medicine, Urmia Medical Science University, Urmia- Iran. Tel: 00989149358500. Email: gharbali@yahoo.com
author
Golbarg
Nourozi
MSc Student, Medical Physics Department, Urmia Medical Science University. Urmia-Iran
author
Leyla
Dinparast
Department of Radiology, Imam Khomeini Hospitalm Urmia Medical Science Universitym Urmia- Iran
author
text
article
2018
eng
Introduction:
To explore diagnostic potential of computerize texture analysis methods in discrimination of the normal, benign and malignant ovarian lesions by CT scan imaging.
Materials and Methods:
Ovarian CT image database consists of 10 normal, 10 benign and 3 malignant which were reported by radiologist and proven by clinical examination. Region of interests (ROI) were defined within the lesions part of the images. Gray level intensity within a ROIs in abnormally part of the image normalized by: N1: default, N2: µ+/- 3σ, where µ and σ respectively were the mean value and standard deviation of the gray level intensity and N3: present intensity limited to 1%-99%. Up to 270 texture features parameters computed for each ROI per normalization schemes. Among them, we selected subsets of ten best discriminating features based on two reduction methods: Fisher (F) coefficient and or the probability of classification error plus average correlation coefficient (POE+ACC). The selected features sets under standard and un-standard states applied for texture analysis with principle component analysis (PCA) and linear discrimination analysis (LDA). The first nearest neighbor (1-NN) classifier was performed for features obtained via PCA and LDA respectively to differential diagnosis benign versus malignant ovarian lesions. Finally, the discrimination performance of the applied texture analysis methods were evaluated by Receiver Operating Characteristic (ROC) curve analysis by calculation sensitivity, specificity and are under the ROC curve ( AZ value).
Results:
In differentiation of normal from benign ovarian lesions, PCA in comparison with LDA, represent excellent performance with a sensitivity 96.7%, specificity 80% and A z value of
0.9. Also in differentiation of benign from malignant ovarian lesions, again PCA represent highly performance with a sensitivity 82.8% , specificity 96.5% and A z value of 0.89.
Conclusion:
Computerize texture analysis has high potential to promote radiologist’s confidence for discrimination of ovarian lesions on CT scan images with no need other examination.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
179
179
https://ijmp.mums.ac.ir/article_12791_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12791
Evaluation of Three-dimensional Treatment Planning System (TPS) performance in dose calculation of virtual wedged fields using film dosimetry
Ahad
Zeinali
PHD of Medical physics ، Department of medical physics، Faculty of medicine ،Urmia Medical Sciences University (UMSU)،
author
samaneh
ganjgahi
MSC of Medical physics ،Department of medical physics ،Faculty of medicine ،Urmia Medical Sciences University (UMSU)، samanehbanoo@yahoo.com
author
Mikael
mollazade
PHD of Medical physics ،Department of medical physics ،Faculty of medicine ،Urmia Medical Sciences University (UMSU)
author
text
article
2018
eng
Introduction: Nowadays radiotherapy plays an important role in cancer treatment. Different radiotherapy techniques improvement emphasizes on using of the precise ، appropriate and useful algorithms. one of these techniques are wedged which is used in radiotherapy to compensate missing tissues and create a uniform dose distribution in tissues. The Siemens Artiste linear accelerator supports a virtual wedge ، that this wedge creates a dose distribution similar to a physical wedge without the use of any extra accessory and wedged profiles are produced moving collimator jaw during irradiation with a constant speed but varying the dose rate. In this study ، TPS performance is evaluated in virtual wedged fields by comparing the calculated and measured results.
Materials and Methods: The calculations were performed by the collapsed cone superposition algorithm based TPS for two tangent fields in anthropomorphic slab phantom using 15،̊ 30̊، 45̊، 60̊ virtual wedges for field size of 20 × 20 cm2 for 6 and 15 MV photon beams. Measurements were produced by Gafchromic EBT films and reading exposed films with scanner.
Results: Good agreement between the measured dose with film dosimetry and calculated dose with collapsed cone superposition algorithm based TPS with using virtual wedge in heterogeneous environment and different energies were found ، with the maximum difference not exceed 3 -5%. The increase in wedge angle due to increase in the difference between calculated and measured data.
Conclusion: : The results from this study showed that the accuracy of collapsed cone superposition algorithm based TPS used with the virtual wedges for two tangent fields is enough for the clinical usage under the studied experimental conditions.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
180
180
https://ijmp.mums.ac.ir/article_12792_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12792
Assessment of adaptive response of gamma radiation in the operating room personnel exposed to anesthetic gases by measuring the expression of Ku 80, Ligase1 and P53 genes
Mahdi
Rajabi-pour
Radiology Department, School of Paramedical Sciences, Shiraz university of Medical, Sciences, Shiraz, Iran,
author
Reza
Fardid
Radiology Department, School of Paramedical Sciences, Shiraz university of Medical, Sciences, Shiraz, Iran,
Ionizing and Non-ionizing radiation protection research center, School of Paramedical Sciences, Shiraz university of Medical, Sciences, Shiraz, Iran
author
Tahereh
Zare
Radiology Department, School of Paramedical Sciences, Shiraz university of Medical, Sciences, Shiraz, Iran,
author
Mohammad Amin
Mosleh Shirazi
adiology Department, School of Paramedical Sciences, &
Ionizing and Non-ionizing radiation protection research center, &
Radiotherapy and Oncology Department, Shiraz university of Medical, Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction: Staffs of operating room are continuously exposed to anesthetic gases and
ionizing radiation. Adaptive response, as a defense mechanism, will occur when cells become exposed to a low dose of factors harming DNA that causes in the next exposures to higher doses of those factors, more resistance and sensibility can be observed. The aim of this study was to investigate adaptive response or synergistic effects of ionizing radiation in the operating room personnel exposed to anesthetic gases by evaluation of the relative gene expression changes of effective genes for DNA repair such as KU80, LIGASE1 and P53.
Materials and Methods: In this study, 20 people of operating room personnel (12 men and 8 women) with an average age of (34/35±7/33), and 20 people from the personnel of other wards (12 men and 8 women) with an average age of (34/05±6/50) were selected as the control group. For every individual’s 2cc heparin blood, RNA extraction and cDNA synthesis were performed. In order to study the adaptive response, a challenge dose of 2Gy gamma radiation was used. Expression level of the genes was studied by Real-Time PCR method and compared with that of the control group. The results were statistically analyzed using SPSS software.
Results: The results showed that expression of Lig1 gene in operating room personnel has a significant increase compared with the control group (p.0.001). After applying the 2Gy challenge dose, the expression of this gene was significantly reduced in the operating room personnel. Nonetheless, in comparison with the control group, a significant difference was observed. Regarding the changes of Ku80 and P53 genes expressions in operating room personnel, no significant difference was observed (P>0.05). However, P53 had a quite significant increase compared with the control group (p.0.001).
Conclusion: The results of the study showed that the exposure to challenge dose of ionizing radiation can create compatibility and adaptive response in expression of the effective genes
for DNA repair such as Ku80 and P53 in operating room personnel.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
181
181
https://ijmp.mums.ac.ir/article_12793_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12793
Study of the Effect of Gamma Radiation on Plasma Levels of Copper and Manganese in Nuclear Medicine Staff
Fereshteh
Faroughi
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Mehdi
Salehi Barough
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction:
Gamma radiations have used frequently at medical radiation centers for treatment of different cancers. This study aimed to consider possible alterations in level of serum zinc and selenium among nuclear medicine staff.
Materials and Methods:
This cross sectional study was carried out on 30 nuclear medicine staff and 10 individuals as control group. After collection of 20 cc blood samples, serum specimens were isolated by centrifuge at 4000 rpm for 7 min and then used for measurement of copper (Cu) and manganese (Mn). Copper and manganese were measured using atomic absorption spectroscopy (AAA) with graphite furnace.
Results:
The mean age of individuals in control and gamma radiated groups were 37 ± 5.77 and 41.83 ± 10.38, respectively (p=0.171). The mean of Cu in the control group (93.85±25.33) was approximately, but not significant (p=0.32) higher than that in radiated group (85.6±21.66). Increased duration of exposure was significantly associated with reduced Cu levels (p=0.05).
Conclusion:
Declined level of Cu can be considered as one of the possible mechanisms of gamma radiation effect on cells which may be associated with oxidative damages. Therefore, antioxidant therapy can be helpful for people who work at medical radiation centers; however, it merits further studies.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
1882
182
https://ijmp.mums.ac.ir/article_12794_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12794
Development of Prototype Iranian male pelvic phantom for internal dosimetry
Fereshteh
Bayani
Faculty of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Farshid
Babapour Mofrad
Faculty of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
author
text
article
2018
eng
Introduction: Existing phantoms have been constructed based on Caucasian, non-Caucasian and race-specific datasets. According to previous studies made efforts to present Korean- specific phantoms and Chinese female phantom based on CVH dataset due to compare the resulting internal dosimetry with the Caucasian based data showed possible racial difference in human anatomy between Caucasian and non- Caucasian populations. These phantoms have been used for internal radionuclide dosimetry and other nuclear-medicine applications. Specific absorbed fractions (SAF) are tools for internal dose estimation of radionuclide intake. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. Many studies have been tried to provide an accurate and reliable data for internal radiation dose calculations. Therefor we construct an Iranian computational phantom to evaluate radiation dose organs within male pelvic region based on Iranian datasets. Internal dosimetry on organ is getting more important from the viewpoint of radiation protection of organ at risk.
Materials and Methods: The first version of computational Iranian male pelvis phantom(PIPM) is provided by 5 MRI datasets of Iranian male for precise organ dose calculation, at first organs within pelvic region are segmented by enhancing their margins in each slice, determination of organs volume then, prototype Iranian male pelvis phantom was developed by modifying the equation of internal organs of the ORNL adult phantom finally, this phantom was imported to general purpose Monte Carlo code to simulate photon transport from internal radiation source.
Results: The results showed that the individual comparable phantom can be calculated with acceptable accuracy using geometric registration. Comparison of dose calculation for Iranian male pelvic, MIRD and RADAR phantoms showed that differences of self-SAF were affected by organ volume differences. The average of the percent SAF deviation was calculated in testes organ -7.73%, -5.53% for PIMP phantom into MIRD and RADAR phantoms respectively. The largest deviation was observed in urinary bladder organ follow as 37.3%, 52.3% into MIRD and RADAR phantoms and it is shown -23.5% variations in self-SAF prostate organ into MIRD phantom. This phantom could be used for absorbed dose calculation of Iranian male pelvic region with acceptable accuracy in nuclear medicine.
Conclusion: A prototype computational Iranian adult male pelvis phantom was represented from 5 Iranian adult males; the results showed that comparable phantom can be calculated internal absorbed dose with significant differences. Accurate voxel phantom is needed for dosimetric simulation in nuclear medicine for malignant tumors in male pelvic region. However, most of the existing voxel phantoms are constructed on the basis of Caucasian or non-Chinese population. It might be provided first Iranian male reference volume organ dataset for future researches.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
183
183
https://ijmp.mums.ac.ir/article_12796_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12796
Automated Tumor Segmentation Based on Hidden Markov Classifier using Singular Value Decomposition Feature Extraction in Brain MR images
Fazel
Mirzaei
MSc. Graduate, Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
author
Mohammadreza
Parishan
Ph.D. Candidate, Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran. parishanmohammadreza@yahoo.com
author
Mohammadjavad
Faridafshin
MSc. Graduate, Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
author
Reza
Faghihi
Associate Professor, Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran. faghihir@shirazu.ac.ir
author
Sedigheh
Sina
Assistant Professor, Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran. samirasina@shirazu.ac.ir
author
text
article
2018
eng
ntroduction:
Diagnosing brain tumor is not always easy for doctors, and existence of an assistant that
facilitates the interpretation process is an asset in the clinic. Computer vision techniques are devised to aid the clinic in detecting tumors based on a database of tumor contained images. These precise techniques open up the way for recognizing a tumor even in the early stages of cancer development depicted as very low contrast object in an image. To this end, at first a set of similarity measures are calculated for each pixel in the image database. Then, this dataset is fed into a classifier that defines the mathematical rules necessary for making decision about a new image. After defining the rules, a model is formed which is ready to make decisions for new images outside the database. This decision is accompanied with an accuracy which is calculated in the end as the classifier performance measures.
Materials and Methods: In this study, Singular Value Decomposition – SVD – method is used as a tool to extract similarity measures for each malignant image in the database. These measures form a matrix with which the classifier is trained. The classifier in this study, is a model based on Hidden Markov Random Field – HMRF – idea, that utilizes Bayes’ rule and maximum a posteriori criterion to obtain labels for each pixel and making decisions about he new images respectively. After sorting the new image as either malignant or not, the malignant image goes through a wavelet process for tumor segmentation. In this section, the image is transformed into a multilevel wavelet structure. Image segmentation is done using direct and inverse wavelet transform.
Results: The classification performance is done quantitatively and qualitatively by calculating Volume Overlap Ratio (VOR), Recognition Rate (RR), True Negative Rate (TNR), True Positive Rate (TPR), Accuracy (ACC), Sensitivity and Specificity parameters, and 5 output images respectively. Also, a qualitative comparison is made between MRF, HMRF and morphological image segmentation methods.
Conclusion: The application of HMRF-Wavelet pattern recognition has been investigated in this work. VOR, RR, TNR, TPR, ACC, Sensitivity and Specificity are calculated, and most values have been reported as over 95% for five test images. Despite the complexity of the HMRF statistical modeling, acceptable performance measure values indicate the sufficiency of this algorithm.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
184
184
https://ijmp.mums.ac.ir/article_12797_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12797
The Impact of Hyperthermia in Radiosensitivity of Human Cervical Carcinoma Cell Line HeLa
Hamid
Fakhimikabir
Department of Medical Physics and Medical Engineering, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran (Email:h.fakhimikabir@gmail.com, Phone: 09102102414)
author
Mohamad Bagher
Tavakoli
Department of Medical Physics and Medical Engineering, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Ali
Zarrabi
Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, Iran
author
Alireza
Amouheidari
Department of Radiation Oncology, Milad Hospital, Isfahan, Iran
author
Soheila
Rahgozar
Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
author
text
article
2018
eng
Introduction: The objective of this work was to investigate the therapeutic effect of a combination of hyperthermia at 43oC exposured for 20, 40, 60 min with 6MeV electron beams at different radiation doses (2, 4, 6 Gy) compared to radiation alone.
Materials and Methods: In this in vitro study, HeLa cells were exposed to either: 6MeV electron beams at different doses (2, 4, 6 Gy) and hyperthermia at 43oC for 20, 40, 60 min alone or electron beam followed by hyperthermia with 20-minute interval. The effect of hyperthermia and radiation alone as well as a combination of radiation with hyperthermia on cell viability and cell survival were estimated using the trypan blue dye exclusion assay and MTT assay immediately and 48 h after treatments, respectively.
Results: The data obtained by trypan blue exclusion test showed that no significant reduction on cell viability when cells were treated RT (6 MeV, 2, 4, 6 Gy) and HT (43oC, 20, 40, 60 min) alone as well as RT followed by HT in comparison with control group (cells without treatment with the RT and HT). In addition, the data obtained by MTT assay showed significant cytotoxicity in the radiated groups compared to the control group. Also, our results showed HT alone did not effect on cytotoxicity. Moreover, our results showed that RT in combination with HT at 43oC for 20 min did not create significance cytotoxicity on HeLa cells in comparison with control group (group treated with radiation) (p>0.05). In contrast, RT in combination with HT at 43oC for 40,60 min had significant cytotoxicity on HeLa cells in comparison with control group (group treated with radiation) (p<0.05).
Conclusion: Our data suggest that combined treatment of 6MeV electron beams (RT) and hyperthermia (HT) can result in radiosensitization of cervical cancer cells.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
185
185
https://ijmp.mums.ac.ir/article_12800_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12800
Radiation-induced bystander effect following hypo- fraction technique of grid therapy by use of sensitive molecular markers
F
Pakniyat
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
H. A
Nedaie
Radiation Oncology Department, Cancer institute, Tehran University of Medical Sciences, Tehran, Iran
author
H
Mozdarani
Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
A
Mahmoodzadeh
Department of Bioscience and Biotechnology, Malek-Ashtar University of Technology, Tehran, Iran
author
S
Gholami
Radiation Oncology Department, Cancer institute, Tehran University of Medical Sciences, Tehran, Iran
author
M
Salimi
Department of medical genetics, Medical biotechnology institute, National institute of genetic engineering and biotechnology, Tehran, Iran
author
text
article
2018
eng
Introduction: Radiation-induced bystander effect (RIBE) is a well-known response associated with the induction of radiation effects in non-irradiated cells via signaling of hit ones. As this so-called phenomenon has been largely investigated in low dose levels, few studies focused on higher dose levels such as grid therapy. Grid therapy or spatially fractionated grid radiation therapy (SFGRT) is a hypo-fraction technique for treatment of advance and bulky malignant tumors. Different advantages of SFGRT including minimal skin side effects and effective tumor control despite the small portion of exposure based on grid pattern, made it as an attractive therapy approach. SO the aim of this research was determination of bystander response following the mentioned therapy method. Materials and Methods: In this study, we evaluated RIBE via distinct protocols of media transfer and cell to cell contact following grid therapy. Two different human cell lines (SCC and Hela) were irradiated by challenging dose of 10 Gy with available grid block attached to the linac head in single radiation field. Irradiation with Grid pattern of 145 circular fields, 13mm in diameter with 17mm center to center distance created the cell to cell contact of directly irradiated and bystander cells. To fulfill the aim of media transfer of our study, bystander cells or grid adjacent cells were irradiated by 1.5Gy receiving the conditioned medium of hit cells. Based on RIBE DNA damage and DSB formation, phosphorylation of histone H2AX could be the novel sensitive marker for early detection of DSBs in intact cells. So Bystander effect has been assessed by use of sensitive molecular biomarkers of gamma h2ax as well as gene expression. Results& Conclusion: Our results indicated the occurrence of RIBE following the high dose hypo-fraction technique of grid therapy and emphasized on the role of sensitive molecular biomarkers in bystander DNA damage mechanism.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
186
186
https://ijmp.mums.ac.ir/article_12801_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12801
An artificial neural network to predict solar UV radiation in Tabriz
Reza
Malekzadeh
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
author
Parinaz
Mehnati
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Ata Allah
Nadiri
Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
author
Yaser
Bagheri
Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
author
Hadi
Sabri
Department of Physics, University of Tabriz, Tabriz, Iran
author
Reza
Meynagi Zadeh Zargar
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Mahak
Osuli
Department of Medical Physics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Solar radiation has a major role in design, utilization, development, and planning of solar energy. The most important source of natural ultraviolet radiation is the sun, which has an important role in many biologic processes. Some of these processes are useful, like the production of vitamin D in the body, or curing rickets, and some of them are not, such as skin inflammation, premature aging, and eye diseases like cornea inflammation and cataracts. Because of lack of important information about the amount of ultraviolet exposure in most cities and weather stations, using methods based on artificial intelligence has been suggested. This study has been conducted to evaluate artificial neural networks ability to predict ultraviolet exposure based on experimental data.
Materials and Methods:
Firstly, the amount of ultraviolet radiation types A, B and C have been measured for a whole year from sunrise to sunset in Tabriz during 2016-2017. To apply the ANN in current study, there are six neurons in the input layer corresponding to the input data (UVA, UVB, UVC, visible light intensity, month of year and hours of day), one hidden layer with three neurons was identified through a preliminary trial-and-error, and one neuron in the output layer for simulate and prediction of solar ultraviolet exposure. Two statistical indexes, RMSE and R2, have been used to evaluate the offered model.
Results:
The predicted results using the artificial neural network in this study, showed that ANN advanced model able to forecast solar ultraviolet exposure, according to error metrics. Average errors obtained for simulation was RMSE=0.0001 with R2=0.98.
Conclusion:
The results showed that developed ANN model is capable of simulating the amount of solar ultraviolet exposure.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
187
187
https://ijmp.mums.ac.ir/article_12803_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12803
Estimated ultraviolet exposure levels for a sufficient vitamin D status in northwestern Iran
Reza
Malekzadeh
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
author
Parinaz
Mehnati
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Hadi
Sabri
Department of Physics, University of Tabriz, Tabriz, Iran
author
Reza
Meynagi Zadeh Zargar
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Mahak
Osuli
Department of Medical Physics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Normal exposure to sunlight results in the production of vitamin D in human body, which happens because of the interaction between ultraviolet radiation and cholesterol in skin. Exposure to sunlight is responsible for 90 percent of vitamin D needed for the body. Studies show that Iran is a country with high percentage of lack of vitamin D (83 percent). Based on previous studies, it has been estimated that if 25 percent of human skin get exposed to sunlight (head, neck, hands and arms), enough vitamin D can be synthesized. In a new definition this amount of vitamin D is called Standard Vitamin D Dose (SDD). In this study the SDD has been calculated and predicted for people who live in Tabriz.
Materials and Methods: First, the amounts of UV type A and B by handheld lux UV-IR meter, for a whole year from sunrise to sunset were measured in Tabriz during 2016-2017. UV indexes were calculated. Skin type of people in Tabriz can be classified in type five (which is specific to people live in Middle East). For this type of skin Standard Vitamin D dose is 260j/m2. Therefor based on existing studies, the relation between ultraviolet index and standard vitamin D dose per hour can be described as follows:
1 SDD = 40 ∗ (260/3600) W/m2 = 2.89UVI
Hour
Now by dividing UVI measured for every hour, standard vitamin D dose for those hours can be obtained. Note that SDD=1 means by exposing a quarter of human skin to sunlight, the necessary amount of vitamin D can be synthesized in the skin.
Results: We can observe that there is a significant difference between the amount of ultraviolet radiation in different seasons, months and hours of the day. During the day, the most amount of radiation can be found in midday, and in all months of the year we can see a good SDD during this period of time. Between the hours of 10 am to 15 pm in all months of the year, the sun light intensity can be reached in less than an hour to meet one SSD.
Conclusion:
The results show that the intensity of ultraviolet radiation is capable of supplying enough vitamin D during year.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
188
188
https://ijmp.mums.ac.ir/article_12804_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12804
Ground Based Measurements of Solar UV Index in Tabriz
Reza
Malekzadeh
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
author
Parinaz
Mehnati
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Hadi
Sabri
Department of Physics, University of Tabriz, Tabriz, Iran
author
Reza
Meynagi Zadeh Zargar
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Mahak
Osuli
Department of Medical Physics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Ultraviolet index (UVI) is a dimensionless scale, which describes the maximum intensity and biologic effects of UV during a specific time, on surface of the earth. The UVI is an international standard measurement of the strength of sunburn producing ultraviolet radiation at a particular place and time. This index is an easy and understandable concept for protection and application for people, which can be described: 2 or less means low exposure, 3-5 means average, 6-7 means high, 8-10 means very high and more than that means dangerous. The major approach is to calculate UVI by measuring the intensity of UV exposure on the surface of earth. In this study we calculated the UVI at Tabriz, based on the measurement of UV intensity.
Materials and Methods: First, the amounts of UV type A and B by handheld lux UV-IR meter, for a whole year from sunrise to sunset were measured in Tabriz during 2016-2017. We use the following formula to calculate UVI:
UVI k er ò E l .w(l)d (l) (1-1)
400
250
ìw(l ) = 1.........................250 < l < 298
ï 0.094 ( 298 - l )
íw(l ) = 10 ..........298 < l < 328 (1-2)
ïw(l ) = 100.015 (139 - l )..........328 < l < 400
î
In which Eλ is the intensity of the specific wavelength reaching the earth, ω(λ) is the biological effect of the specific wavelength and Ker is a constant which is 40 m2/W.
Results: Our results showed that the maximum UVI occurs between 12 and 13 o'clock. Maximum and minimum Data was obtained in May and January respectively. For the summer and spring months, the amount of UVI is more than 10 in the 12 to 15 hours. In Just two month of the year, UVI is less that average, even in noon.
Conclusion: Except for winter, UV exposure is high in noon (12 to 15 o'clock) and we
recommend avoiding the direct sun exposures.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
189
189
https://ijmp.mums.ac.ir/article_12806_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12806
Assessment of polymer composite reinforced with nanomaterial against ionizing radiation
Hasan
Norouzi
Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences.
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences
author
Karim
Khoshgard
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences
author
Abbas
Haghparast
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences
author
Mohammad taghi
Eivazi
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences
author
text
article
2018
eng
Introduction: Unwanted exposure of ionizing radiation may result in carcinogenesis, cell mutations, and organ failure. High-atomic number elements such as lead, tungsten, bismuth have been traditionally used for radiation protection. Theoretical and practical studies have shown that a variety of shielding materials e.g. polymer composites (PCs) can be used for attenuation of the undesired ionizing radiations. The goal of the present study is to review the efficacy of the PCs reinforced nanomaterials (NMs) for routine protection.
Materials and Methods: The relevant papers were searched in PubMed, Ovid, and Scopus databases using "polymer composite", "radiation", and "protection" as keywords. Literature containing information of recent developments based on PCs reinforced nanotechnology was evaluated. The selected studies were examined using the following topics as guidelines: the PCs effectiveness on the shielding to obtain As Low as Reasonably Achievable (ALARA), focus on high energy/charge, and overall recommendation for clinical practice.
Results: High atomic numbers materials such as lead is used for shielding against high- energy X and γ-rays. In addition to the fact that such substances may not be able to attenuate all photons of the incident radiation; production of secondary radiation is also probable in them. This requires additional shielding may increase the weight of the shield and its cost. The most serious problem with the routine radioprotective instruments, made from these materials, is that they are heavy and bulky. The radiation type and energy are the other important factors governing the radiation shielding design. Nowadays, novel shielding materials have been introduced in which some problems including weight, toxicity, cost- effectiveness, and durability have been improved. A variety of PCs have been investigated for radiation shielding; however, only the PCs reinforced with NMs have shown the effectiveness of radiation attenuation. This is because of the large surface-to-volume ratio and the concept of “self-healing or self-repair”. ”. In PCs shielding, regardless of the material being used, the absorption was independent of the atomic number of material and can be customized according to the specific application (radiation type). To obtain maximum protection, based ALARA, with PCs shielding, using few heavy atoms within the light matrix is necessary. Many studies have showed shielding using PCs reinforced with NMs absorb effectively fast neutrons and also can reduce the secondary gamma radiations and thermal neutrons.
Conclusion: Polymers reinforced with micro- or nanoscale structures have great potential to be used as radiation shielding materials in medical uses, aerospace, and nuclear reactors.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
190
190
https://ijmp.mums.ac.ir/article_12807_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12807
Prediction of solar ultraviolet intensity by using Fuzzy Logic in the north-west of Iran
Reza
Malekzadeh
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
author
Parinaz
Mehnati
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
ta Allah
Nadiri
Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
author
Yaser
Bagheri
Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
author
Hadi
Sabri
Department of Physics, University of Tabriz, Tabriz, Iran
author
Reza
Meynagi Zadeh Zargar
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Mahak
Osuli
Department of Medical Physics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Solar energy is one of the free sources, clean and environmentally friendly energy. Sun is the most important source of natural ultraviolet radiation that has a major role in the life of living beings. Industrial and medical applications of ultraviolet radiation have been clearly proven, like the production of vitamin D or treatment of many diseases, and also harmful effects such as diseases related to skin and eyes. Therefore, prediction of UV exposure reaching the surface of the earth is an important subject in health, ecosystem and economy related concerns, which can affect efficiency, and increase the use of renewable energy sources. In this study fuzzy logic has been used to predict the amount of UV exposure in Tabriz.
Materials and Methods:
Intensity of solar UV radiation type A, B and C have been measured for a whole year from sunrise to sunset in Tabriz during 2016-2017. These data then were given to fuzzy logic model, along with sunny hours of day and moths of the year, as input to simulate and predict the solar UV exposure. Two statistical indexes, RMSE and R2, have been used to evaluate the presented model.
Results:
Considering the results of the proposed model with the experimental data, this model can predict the solar exposure accurately. Average errors obtained for simulation was RMSE=0.001 with R2=0.99.
Conclusion:
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
191
191
https://ijmp.mums.ac.ir/article_12809_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12809
Comparison of three and four-field radiotherapy technique and the effect of laryngeal shield on vocal and spinal cord radiation dose in radiotherapy of non- laryngeal head and neck tumors
Noushin
Hasan Pour
Department of Medical Physic, Faculty of Medicine, Tabriz University of Medical Science, Tabriz, Iran
author
lireza
Farajollahi
Department of Medical Physic, Faculty of Medicine,
Medical Education Research Center,
Imam Reza University Hospital, Radiotherapy Department, Tabriz University of Medical Science, Tabriz, Iran
author
Ahad
Zeinali
Department of Medical Physic, Urmia University of Medical Science, Urmia, Iran
Radiotherapy Center of Omid Hospital, Urmia, Iran
author
Masoud
Jamali
Radiotherapy Center of Omid Hospital, Urmia, Iran
author
Amir
Ghasemi Jangjou
Imam Reza University Hospital, Radiotherapy Department, Tabriz University of Medical Science, Tabriz, Iran
author
text
article
2018
eng
Introduction:
Due to the effect of radiation on both the tumor and the surrounding normal tissues, the side effects of radiation in normal tissues are expected. One of the important complications in the head and neck radiotherapy is the doses reached to the larynx and spinal cord of patients with non-laryngeal head and neck tumors.
Materials and Methods:
In this study, CT scan images of 25 patients with non-laryngeal tumors including; lymph nodes, tongue, oropharynx and nasopharynx were used. A three-field and a four-field treatment planning with and without laryngeal shield in 3D CRT technique were planned for each patient. Subsequently, the values of Dmin, Dmean, Dmax and Dose Volume Histogram from the treatment planning system and NTCP values of spinal cord and larynx were calculated with BIOPLAN and MATLAB software for all patients.
Results:
Statistical results showed that mean values of doses of larynx in both three and four-field methods were significantly different between with and without shield groups. Comparison of absorbed dose didn’t show any difference between the three and four field methods (P>0.05). Using Shield, just the mean and minimum doses of spinal cord decreased in both three and four fields. The NTCP of the spinal cord and larynx by three and four-field methods with shield in the LKB and EUD models significantly are less than that of the three and four fields without shields, and in the four-field method NTCP of larynx is less than three radiation field.
Conclusion:
The results of this study indicate that there is no significant difference in doses reached to larynx and spinal cord between the treatments techniques, but laryngeal shield reduce dose and NTCP values in larynx considerably.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
192
192
https://ijmp.mums.ac.ir/article_12810_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12810
Frequency of Congenital Renal Anomalies by Tc99m- DMSA Renal Scan in Children Referred to Birjand Nuclear Medicine Center
Fatemeh Zakieh
Tohidi
Corresponding author Department of Medical Physics , Zahedan University of Medical Sciences, Zahedan, Iran.
author
Faride
Pursoltani
department of radiology, Birjand University of Medical Sciences, Birjand, Iran
author
Mohadeseh
Tohidi
Physics Dept., Payame Noor University of Mashhad, Mashhad, Iran
author
text
article
2018
eng
Introduction:
Tc99m-DMSA renal scan findings of this project was to study aimed to determine the frequency of congenital anomalies of the kidney. Obtain the spectrum of anomalies, can be used for future intervention studies. Using the experience gained from this study and future studies may be conducted and mitigation measures to achieve a specific distribution.
Materials and Methods:
In this descriptive - analytic study of 41 children from 1 month to 12 years who were referred to the nuclear medicine Birjand on 01/01/90 to 07/30/91 on non-probability sampling were selected With the Czech List Frequency congenital renal scanning Tc99m-DMSA for 19 months collecting and using version 19, SPSS, descriptive tables extracted from the chi- square test or Exact Fisher test for statistical analysis at a significance level of 0 / 05 was used .
Results:
In this study, age 4/51 ± 3.40, 4 types of congenital renal anomalies in 12 boys (29/3%) and 29 females (70/7%) were. 32 patients (78%) had normal renal and 9 patients (22%) had abnormal kidney. Most common congenital anomalies of the kidney include Absent, Duplex in 6 (66/6%) were.
Conclusion:
An anomaly in this study between age and the age of the child during pregnancy, birth, baby's sex, place of residence, the child who found no significant relationship. In this study, the most common congenital renal Absent, Duplex were.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
194
194
https://ijmp.mums.ac.ir/article_12811_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12811
Assessment of radiation dose distribution of different radioisotopes used to treatment of bone metastasis and pain relief patients in a bone model of foot
Fatemeh
Razghandi
MSc in Nuclear Physics, School of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
author
Ruhollah
Ghahramani Asl
Assistant Professor of Medical Physics, Faculty of Paramedicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
author
text
article
2018
eng
Introduction:
Although there are several ways to relief pain in metastatic patients, the use of radionuclides is one of the known and effective ways to relieve the pain caused by bone metastases. The purpose of this study was to assessment of radiation dose distribution of different radioisotopes used to treatment and pain relief patients in a bone-based model based on Monte Carlo simulation for particle transport.
Materials and Methods:
Distribution of radiation dose of six different radioisotopes such as Sm-153, Re-188, Lu-177, Re-186, Sr-89, Ra-223 was done in a foot-bone model using the MCNPX computational code for particle transport. The RADAR decay nuclear data on gamma and beta radiation and the probability emission of each, as well as the recommended ICRU and ICRP data for bone marrow, bone and soft tissue components were used in the dose calculations.
Results:
After performing of simulation calculations, the absorbed dose spectrums of gamma and beta- rays of radioisotopes mentioned above were calculated according to foot phantom radius, separately. Also, bar charts were used for comparison of the absorbed dose to bone marrow, bone and soft tissue. The highest dose delivered to the bone was related to Ra-223 alpha ray and beta ray of Re-188 and Sr-89.
Conclusion:
The delivered absorbed dose to the bone tissue as a therapeutic target by alpha ray of Ra- 223 and beta rays of Re-188 and Sr-89 was maximum and the amount of absorbed dose delivered to bone marrow and soft tissue by gamma rays of Sr-89 and Re-188 was high. Accordingly, the choose of widespread clinically used radioisotopes such as Sr-89 and Sm- 153 to treatment and pain relief patients seems to need be revised and more careful.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
195
195
https://ijmp.mums.ac.ir/article_12812_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12812
The effect of cell phone radiation on blood and cancer Risk
fatemeh zakieh
tohidi
Department of Radiology, Birjand University of Medical Sciences, Birjand, Iran .and Department of Medical Physics, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Mohammad Hosein
Bahrayni Toosi
Medical Physics Dept., Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mohadeseh
Tohidi
Physics Dept., Payame Noor University of Mashhad, Mashhad, Iran
author
text
article
2018
eng
Introduction:
The continuous rapid growth of the telecommunications industry and common application of cell phones have raised debates on the human health risks associated with exposure to radio frequency fields due to these phones or their base stations and other sources such as radar, radio/television waves, and industrial and medical applications. This study aimed to investigate the effects of cell phone radiation on blood factors and Cancer Risk.
Materials and Methods:
In this study, 48 mice were divided into 6 groups of 8 (one control, and 5 exposure groups). The 4 exposure groups, twice daily were exposed to radiation waves for 30 minutes, one, two, and 4 hours and the fifth exposure group is 4 hours’ single fraction radiation once day at 900 and 1800 MHz at 2 watts’ power, over a period of one month. Then blood samples were taken from the heart and blood factors were analyzed and The hippocampal expression of P21and P53 mRNAs were evaluated using Real-Time PCR.
Results:
Of the 10 blood factors, only mean concentration of cell hemoglobin (MCHC) in the 0.5 hours’ exposure group, and mean value of the mean cell hemoglobin (MCH) in 0.5, 2, and 4 hours’ exposure groups, showed a significant difference with those of the control group (P<0.05). The ratio expression of P53 and P21 genes was increased to greater than one (P53/P21>1) in all experimental groups compared to controls, except for the group with 2 hours twice a day exposure. However, there was not significant differences between the expression level of P53 and P21 genes among the experimental groups using paired t test (p>0.05).
Conclusion:
Since human’s whole body is exposed to electromagnetic radiation from mobile phones and antennas, some blood factors could be, to a small extent, affected by adverse effects of mobile phone electromagnetic waves. In fact, radio frequencies of mobile phones damage brain cells depending on the duration of the conversation (the duration of radiation).
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
196
196
https://ijmp.mums.ac.ir/article_12813_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12813
Core/Shell structured nanoparticles for imaging and therapy
Behnaz
Babay Abdollahi
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Hamed
Hamishehkar
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
author
Marjan
Ghorbani
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
author
Ali Reza
Naseri
School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Imam Reza University Hospital, Radiotherapy Department, Tabriz, Iran
author
Ali Reza
Farajollahi
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Imam Reza University Hospital, Radiotherapy Department, Tabriz, Iran
author
text
article
2018
eng
Introduction: Nanoparticles have several exciting applications in various fields of biomedicine. It has been found that among different classes of nanoparticles core/shell is most promising for field of nano-medical imaging and therapy due to their distinct advantages. The core/shell type nanoparticles can be generally comprising of two nanoparticles one act as a core (inner material) and the second act as a shell (outer layer material). the aim of this study in brief is to explore a historical review of the core/shell nanoparticles in past two decades.
Materials and Methods: An organized search of Web of Science, Google Scholar and Scopus was made to select papers with different classes of Core/Shell nanoparticles from the time of introduction to August 2017. The search was limited to English language documents. Titles and abstracts were carefully assessed.
Results: Eighty - nine studies were considered as relevant for this review. Of these 64, 18 and 7 studies were classified as inorganic/inorganic, inorganic/organic or organic/inorganic, and organic/organic material core/shell nanoparticles. In general, it is considering that inorganic/inorganic (metal or metal-oxide) core/shell nanoparticles are the most common and important class of all the different types of core/shell nanoparticles but still there are lots of work need to be done in order to verify their applications.
Conclusion: It seems that, core/shell nanoparticles have strikingly superior over simple nanoparticles and also the inorganic/inorganic core/shell nanoparticles are extensively studied due to their wide applications in cancer treatment, bio imaging and cell targeting.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
197
197
https://ijmp.mums.ac.ir/article_12814_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12814
Mobile Phone Radiation exposure effects on Bax and Bcl-2 Genes Expression in hippocampal formation of mice brain
Fatemeh Zakieh
Tohidi
Corresponding author Department of Medical Physics , Zahedan University of Medical Sciences, Zahedan, Iran
author
Mohammad Hosein
Bahrayni Toosi
Medical Physics Dept., Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mohadeseh
Tohidi
Physics Dept., Payame Noor University of Mashhad, Mashhad, Iran
author
text
article
2018
eng
Introduction:
The increasing use of electromagnetic field generators in our daily life in one hand and on contradictory reports on the effects of their waves on public health on the other hand encourages scientists to do more and more research work in this field. One of the most important topics is the study of gene defect due to microwave radiation.
Materials and Methods:
In this study, 48 Balb/c adult (8-9 weeks old) male mice were randomly divided into six groups, five of which as test (exposure) groups and the sixth as the control group. The mice in the test groups were exposed to 900 &1800 MHz commonly used in mobile telecommunication. Microwaves produced by a Mobile wave generator were induced on the mouse for half an hour, one hour, tow hours and four hours twice a day (0.5h×2, 1h×2, 2h×2 & 4h×2) and four hours once a day (4h). Control groups were kept in the same living conditions as test groups. After 30 consecutive days, hippocampus was separated and the total RNA isolation and cDNA synthesis was carried out. Bax and Bcl-2 genes expression was quantified by Real-Time RT-PCR.
Results:
Results showed that Bax and Bcl-2 gene expression average increased with exposure time during the frist hour of exposure time, after which it was decreased. Comparison of Bax and Bcl-2 gene expression average showed significant difference in some groups. Bax to Bcl-2 gene expression ratio in all test groups was over 1 ( 1). The difference between Bax and Bcl-2 gene expression in all groups was not significant (p > 0.05).
Conclusion:
on the results of this research we concluded that microwave radiation (900&1800MHz) could cause expression changes of Bax and Bcl-2 genes in hippocampal formation of Balb/c mouse brain. These changes depended on the duration of exposure. Effects of longer exposure time (4h×2) may cause apoptosis in hippocampal formation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
198
198
https://ijmp.mums.ac.ir/article_12815_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12815
Comparing of different normal tissue complication probability models for plan evaluation of radical radiotherapy for esophageal cancer
Hamid
Abdollahi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Mohammad Amin
Mosleh-Shirazi
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Seyed Mohammad Javad
Mortazavi
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Medical Physics and Medical Engineering, Shiraz University of Medical Sciences, Shiraz, Iran
author
Shapour
Omidvari
Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction:
Chemoradiation is a well-established protocol for management of localized esophageal cancer. However, some early and late toxicities are associated with this therapy. Plan evaluation in term of normal tissue complication probability (NTCP) may help clinicians to tailor this therapy more individually. Given the variety of present radiobiological models, the choice of a model that is suitable for this purpose remains an issue. The purpose of this study was to compare different NTCP models and parameters for plan evaluation of radical radiotherapy for esophageal cancer, in terms of mean values and ranges of predicted NTCPs for four different radiation-induced normal tissue endpoints.
Materials and Methods:
Eight patients with localized esophageal cancer were included in the study. The patients had been treated in two phases and received 54 Gy in 30 fractions. Dose volume histogram data for heart, lungs and spinal cord were extracted from the treatment planning system and were considered as the main organs-at-risk for NTCP evaluation. Three NTCP models, namely, Lyman-Kutcher-Burman (LKB), Relative Seriality (RS) and Parallel with their corresponding sets of published parameters were used for plan comparisons for the following endpoints: radiation induced pericarditis, ischemic heart disease, pneumonitis and myelopathy.
Results:
For radiation induced pericarditis and ischemic heart disease, the predicted NTCP value ranges were 5%-50% and 10%-40% by the LKB and RS models, respectively. For pneumonitis, both the LKB and RS models predicted similar NTCPs (1-5%) depending on the parameters used. The Parallel model also gave similar results. For radiation myelopathy, the LKB model predicted NTCPs of <5%. However, there were no RS and Parallel model parameters available for prediction of radiation myelopathy.
Conclusion:
For the treatment technique studied, the patient plans showed greater mean values and range of NTCPs for radiation-induced pericarditis and ischemic heart disease compared to pneumonitis and myelopathy. The four models showed general agreement. However, availability of reliable model parameters still remains a challenge to routine use of radiobiological model in clinical decision making, which requires further studies.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
199
199
https://ijmp.mums.ac.ir/article_12816_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12816
Activation of Radioadaptive Response via Injected Serum of Irradiated Rats with Low Doses of Ionizing Radiation
Rasool
Azmoonfar
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Ehsan
Khodamoradi
Assistant Professor of Medical Physics, Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Mohammad
Mohammadi
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Amir
Kiani
Associate Professor at School of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Abbas
Haghparast
Associate Professor at of Medical Physics, Medical physics Department, Medical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
N
Sharafi
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
text
article
2018
eng
Introduction:
One of the protective concepts in the interpretation of radiation damage in radiobiology is the radioadaptive response. The objective of this present report is to evaluate the induction of radioadaptive response in male rats by injection of pre-irradiated serum with low doses X-radiation intraperitoneally.
Materials and Methods:
80 male adult Wistar rats were randomly divided into 6 groups include control (sham exposed), serum control (injected blood serum of non-irradiated rats), low dose(100cGy), low dose/lethal (100cGy then 8Gy), serum/lethal(injected blood serum of irradiated rats+8Gy). and lethal(8Gy). In this study, we have monitored the end points of survival rate; the first stages, rats were exposed to low doses of radiation (100cGy), then, the serum was injected intraperitoneally under sterile conditions and under the laminar hood 6hour after low dose exposure. The Kaplan Meier Survival Curve was used to evaluate survival rate in the studied groups p< 0.05 is considered as significant between groups.
Results:
We found that there was a significant difference between the survival rates in different groups. There were no deaths in the control, serum and low dose groups at 13, 18, and 22 days after the start of the experiment and survival rates was 100%. Statistically significant difference between low dose/lethal and low dose/serum, low dose/lethal and lethal, and low dose /serum and lethal (p=0.001). Likewise, the data confirm that a statistically significant difference between survival rates of the rats in control and test groups was observed (p=0.001).
Conclusion:
In conclusion, this Study showed that exposure to low dose radiation and then serum injection to adapting group may induce a significant survival adaptive response.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
200
200
https://ijmp.mums.ac.ir/article_12817_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12817
A free user friendly program for evaluation of radiotherapy plans based on different dose response models
Hamid
Abdollahi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Mohammad Amin
Mosleh-Shirazi
Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction:
Radiotherapy (RT) plan evaluation using dose response models has become a feasible approach in routine clinical practice. Although there are several tools for this task, they suffer from limitations including number of different dose response models and parameters. In the present study, we aimed to develop a free program for RT plan evaluation based on a variety dose response models and parameters.
Materials and Methods:
The program was developed in MATLAB. It includes four dose response models for normal tissue complication probability (NTCP) including Lyman-Kutcher-Burman (LKB), Relative Seriality, Logit and Parallel. The program required dose-volume histogram (DVH) data, number of fractions and the total RT dose. Other user inputs include a number of model parameters which are available in separate sheets. The program also calculates biological effective dose (BED), equivalent uniform dose (EUD) and biological equivalent uniform dose (BEUD). To evaluate the program, its results from sixteen patients were compared against previously validated software codes. Each model’s results were compared for various parameters. The computed NTCP, BED, EUD and BEUD values were compared with the expected values using a spreadsheet.
Results:
There was a good agreement between the results of our program and the standard software. Different model parameters resulted in different predicted values depending on the model and the parameters used. All calculated dose response outputs were calculated exactly the same as the standard codes.
Conclusion:
The results presented here indicate that the developed program is validated. This free and user friendly software can help physicists and clinicians to evaluate treatment plans on a radiobiological basis using different models directly and easily.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
201
201
https://ijmp.mums.ac.ir/article_12818_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12818
Assessment of Awareness, Performance, and Attitudes of Radiographers Toward Radiological Protective Principles in jahrom
text
article
2018
eng
Introduction: With the rapid advancement of technology in today's world, the use of ionizing radiation and radioactive materials has been expanding significantly. The use of radioactive resources and equipment in medical sciences is increasing. Failure to observe safety precautions when working with radiation can have serious risks for employees, people, the environment and even future generations. Recognizing the damage caused by ionizing radiation and familiarity with the principles of protection against ionizing radiation by workers can play an important role in protecting them. The aim of this study is to determine the level of knowledge, attitude and practice of radiation workers on the principles of radiation protection in medical imaging centers of Jahrom.
Materials and Methods: This cross-sectional descriptive study was performed on a 30-item questionnaire in Jahrom radiology and CT scan centers Data were analyzed by descriptive statistics, Pearson correlation test and spss19 software.
Results: The result of this study showed that increasing the level of education did not increase awareness, performance and attitude to the principles of protection against fatigue. There is also a significant relationship between the years of work and awareness, but there is not a significant relationship between work years and performance and attitude.
Conclusion: According to the obtained results, the following suggestions have been made to increase the employees' knowledge and their impact on their health behavior:
1-To raise awareness of radiation protection for radiation workers, it is better to hold training courses. 2- The possibility of continuing education for radiology staff
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
202
202
https://ijmp.mums.ac.ir/article_12819_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12819
Iterative Approach for Automatic Beam Angle Selection in Intensity Modulated Radiation Therapy Planning
Ali
Ghanbarzadeh
PhD Candidate, Department of Medical Radiation Engineering, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran.
author
Majid
Pouladian
Department of Biomedical Engineering, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran.
author
Ali
Shabestani Monfared
Professor, Cancer Research Center, Medical Physics Department, Babol University of Medical Sciences, Babol, Iran. (monfared_ali@yahoo.com)
author
Seied Rabi
Mahdavi
Associated Professor, Radiobiology Research Center, Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran. (srmahdavi@hotmail.com)
author
text
article
2018
eng
Introduction:
Beam-angle optimization (BAO) is a computationally intensive problem for a number of reasons. First, the search space of the solutions is huge, requiring enumeration of all possible beam orientation combinations. For example, when choosing 4 angles out of 36 candidate beam angles, C36 = 58905 possible combinations exist. Second, any change in a beam
4
configuration requires re-calculation and re-optimization of intensity maps, itself a time-
consuming process. Third, many local minima (maxima) will appear in the objective function. This paper introduces a new framework to beam-angle selection in intensity modulated radiation therapy (IMRT).
Materials and Methods: In the proposed algorithm for beam angle selection, the problem is solved in two iterative steps: (1) For all beam that given in search space, the fluence map optimization is done to minimize an objective function that is based on clinical requirement and then used to scoring each beam direction. (2) the proposed algorithm is eliminated an insignificant beam angle (with the lowest score in step one) from search poll in each iteration until the beam selection algorithm is received to the predefined number of angles to be used for the treatment.
To accelerate each iteration of dose calculation, dose matrix was precalculated in which the dose deposited in voxel i by an IMRT beam is given by Di = ∑ Kimxm where xm is the weight for the mth beamlet. the efficiency of the algorithm was examined in two clinical cases (TG- 119 phantom and prostate case) in terms of DVH and dose distribution. In all cases, the judgment of the algorithm’s efficiency was based on the comparison between plans with equi-spaced beams and plans with beams obtained using the algorithm.
Results: the beam selecting framework has been tested for both a simulated and clinical case(prostate), and the results show the target coverage and dose uniformity remains essentially unchanged, the mean and maximum dose of OARs is significantly decrease as a result of beam selection. For example, in prostate case, the mean dose of rectum and bladder reduced 10.2% and 7.6% respectively. Moreover, D95 of bladder decreased from 10.13 Gy in equiAngular beam selection to 20.3 Gy by the automatic beam angle selection.
Conclusion:This study demonstrates that the algorithm can be effectively applied to IMRT scenarios to get case specific beam angle configurations.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
203
203
https://ijmp.mums.ac.ir/article_12820_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12820
Consider potential of gold nanoparticles with proton therapy compared with KV and MEV X-ray therapy.
Hasan
Norouzi
Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences.
author
Kambiz
Varmira
Research Center of Oils and Fats (RCOF), Food and Drug Administration (FDA), Kermanshah University of Medical Sciences.
author
Karim
Khoshgard
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences.
author
Abbas
Haghparast
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences.
author
text
article
2018
eng
Introduction:
Many study shown the effectiveness dose enhancement with gold nanoparticles (GNPs), especially with low-energy x-rays. Recently, proton beam radiation therapy (PBRT) has attention as a treatment for tumors. The advantage in PBRT, which releases high dose at the controllable Bragg peak position that localized for Au target and the released dose increased in depth. In this paper we consider potential of GNPs with PBRT in compared conventional radiotherapy.
Materials and Methods:
This paper prepared by searching the latest relate paper with keywords such as gold nanoparticles and proton therapy in PubMed and Scopus databases.
Results:
Several research considerate GNPs dose enhancement in in vitro and in vivo for PBRT and showed increasing tumor cell kill. Many study reported that GNPs internalization into tumor cells, the effect of dose enhancement increases. Some study compared the dose deposited by secondary electrons generated from GNPs interacting with clinical spread out Bragg peak proton, kV and MV photon beams that secondary electrons produced by kV photons have a longest range up to 20 times and dose enhancement using protons can be up to 14 times that is independent of proton energy, while the dose enhancement is highly dependent on the photon energy used. Some studies report that the mechanism which GNPs can lead to dose enhancements in radiation therapy differs when comparing photon and proton radiation.
Conclusion:
Although radio-sensitization enhancement factor is highest for KV photon due to the highest probability of interaction with GNPs, but proton therapy with GNPs showed many potentials. Since protons are loading less cumulative dose compared to photons, especially when combined with the GNPs, it can be considered as the preferred method for treating tumors in children. The results will enable us to project the radio-sensitizing effect in clinical applications of proton therapy with GNPs. Direct distribution of proton’s energy is the major advantage of proton treatment over conventional radiation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
204
204
https://ijmp.mums.ac.ir/article_12821_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12821
The influence of neutron contamination on pacemaker in photon beam radiotherapy by LINAC using the Monte Carlo method
Maryam
Dehghanpour
Islamic Azad University, Science and Research Branch, Tehran University of Medical Sciences, Tehran, Iran. . E- mail:Mdehghan72@ymail.com. Tel: +98 9166692961
author
Asghar
Hadadi
Islamic Azad University, Science and Research Branch, Tehran University of Medical Sciences, Tehran, Iran. .
author
Somayeh
Gholami
Department of Radiotherapy, Cancer Institute, Tehran University of Medical Sciences
author
Reza
Molazadeh
Department of Cardiology, Imam Khomeini Hospital, Tehran University of Medical Sciences
author
text
article
2018
eng
Introduction: In radiation therapy with high-energy photon beams (E > 7 MeV) neutrons are generated mainly in LINACs head thorough (γ, n) interactions. These neutrons affect the shielding requirements in radiation therapy rooms. According to the protocol TG-34, photon absorbed dose of 10Gy can cause permanent damage to the pacemaker and the dose of 2Gy can make minor changes in the functioning of the pacemaker. So, in the radiotherapy of patients with pacemakers, the system should be designed to limit the dose of the pacemaker to 2Gy. In the current study, the Varian Clinac 2100C linear accelerator head and the pacemaker were fully simulated, the neutron and photon flux were evaluated by the FLUKA code.
Materials and Methods: The linear accelerator Varian 2100c is simulated in 18 MeV energy using FLUKA code. A 70 × 40 × 20 cm3 water phantom simulated upper body of patient, at a distance of 100 cm from the source (SSD). According to the MIRD Phantom, the prostate is simulated at a depth of 4.5 cm from the phantom surface at a distance of 50 cm from the pacemaker. All components of the heart pacemaker, including battery and circuit parts, leads and connector were simulated according to real case. The results of the simulation were compared with measurements to verify the simulated model.
Results: According to the distribution results of neutron flux around the head, the jaws despite of guide and control of photon beam toward the phantom, these components are not an effective barrier to neutron contamination, but also because of the heavy elements used in them, exacerbate the production of neutrons. The highest level of contamination is in target, due to photoneutron production in tungsten. Moreover, the distribution of neutron flux in the water phantom and the pacemaker shows a relative increase in neutron flux at a depth of 2 cm in the water phantom caused by the effect of build-up and neutron accumulation that is due to the neutron scattering within the phantom.
Conclusion: For the treatment of prostate cancer where the pacemaker is located more than 40 cm from the treatment field, the neutron flux is observed in a wide range of thermal neutrons to fast. Therefore, in addition to the target tissue that receives the highest unwanted neutron dose during treatment, close organs and, subsequently, other organs receive a considerable dose of neutrons. The highest amount of flux on the surface of the titanium body of the pacemaker is for 100 keV photons and the most of the neutron flux is in the thermal region. The results of photon and neutron flux in the battery layers show that the maximum flux is in steel layer and then for lithium.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
205
205
https://ijmp.mums.ac.ir/article_12822_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12822
Image-guided prostate radiotherapy: analysis of inter- fractional setup errors
Hamed
Ghaffari
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Mohammad
Haghparast
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
Department of Radiology, School of Paramedicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
author
Seyed Rabi
Mahdavi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Mahdieh
Afkhami
Department of Radiology, School of Paramedicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
author
Hajareh
Ghaderzadeh
Department of Radiation Oncology, Roshana Radiation Oncology Center, Tehran, Iran
author
text
article
2018
eng
Introduction:
The accuracy of the patient setup and tumor location are major factors that determine the efficacy of radiotherapy treatment planning. In the prostate radiotherapy, reproducibility of the prostate location for each treatment fraction is problematic owing to varying filling of the rectum and bladder. According to this, the aim of this study was to measure the inter- fractional setup errors using gold markers implanted into the prostate and electronic portal imaging device (EPID). The results were used to determine optimal CTV-PTV (clinical target volume-planning target volume) margin.
Materials and Methods:
Image-guided three-dimensional conformal radiotherapy (3DCRT) was performed by daily online verification of implanted fiducial prostate markers using a megavoltage EPID. In this retrospective study, a total of 359 image-guided treatment fractions from 15 prostate cancer patients were analyzed. PTV was defined as an isotropic margin of 5 mm around of CTV. Daily electronic portal images (EPIs) compared to reference digitally reconstructed radiographs (DRRs), the setup errors were determined and online corrections applied. Mean displacements, population systematic and random errors were calculated. CTV-PTV margin was determined using van Herk’s formula.
Results:
The mean shifts in the vertical, longitudinal and lateral directions were 0.31 mm, 0.22 mm and – 0.41 mm, respectively. The population systematic and random errors in the three mentioned translational directions were 0.70 mm, 0.80 mm and 1.00 mm and 2.11 mm, 2.24 mm and 2.20 mm, correspondingly. CTV-PTV margin of 3.23 mm, 3.60 mm and 4.04 mm in the vertical, longitudinal and lateral directions were calculated.
Conclusion:
The calculated PTV margin was less than 5 mm, therefore PTV margin applied in this study provides a sufficient PTV coverage. Daily EPIs combined with gold markers implanted into the prostate provide an effective tool for verifying of the prostate position immediately prior to treatment delivery.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
206
206
https://ijmp.mums.ac.ir/article_12823_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12823
Radio-protective effects of Hesperidin against gamma radio-radio-protective effects of Hesperidin against gamma radiation induced histopathological changes in the liver of Sprague Dawely rats
Zhila
Ghorbani
MSC of Radiobiology & Radiation Protection, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran. E-mail address . Tel: +98 9104593624
author
Reza
Fardid
Assistant Professor of Medical Physics, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
author
Gholam Hasan
Hadadi
Associate Professor of Medical Physics, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
author
Amin
Derakhshanfar
Professor of Pathology, Diagnostic Laboratory Sciences and Technology Research Center, Basic Sciences in Infection Diseases Research Center, Center of Comparative & Experimental Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
author
text
article
2018
eng
Introduction: Despite the extensive use of ionizing radiation in diagnosis and therapeutic procedures, development of radio-protector agents is important in modulating normal tissue damages. Hesperidin(HES) is a Flavanone glycoside, belonging to the Flavonoid family in human diet abundantly and noted for its many beneficial effects. The aim of present study was investigated to the radio-protective effects of Hesperidin on radiation-induced hepatotoxicity in male Sprague Dawely rat.
Materials and Methods: 40 male Sprague Dawley rats were selected randomly and divided into 8groups: control, Hesperidin (100 mg/kg body weight, orally, 7 days), whole body gamma radiation with 2 Gy and 8 Gy, pre-administrated with 50 and 100 mg/kg body weight of Hesperidin for 7 days before irradiation with 2Gy and 8 Gy, respectively. Histopathological evaluation was done 24 h after radiation.
Results: Administration of Hesperidin (50 and 100 mg/kg b.w, orally, 7 days) before 2 Gy of gamma radiation led to remove inflammatory mononuclear cells in the portal space but there was still dilation of central veins while hesperidin at a dose of 100 mg/kg before 2 Gy gamma radiation was observed normal liver structure. Microscopic findings in the groups in the groups receiving two doses of Hesperidin (50 and 100 mg/kg b.w , orally, 7 days) before 8 Gy of gamma radiation was similar , in this way that extreme dilation of central veins to be seen but there was no capillarization.
Conclusion: Based on the finding in this study, it shows that Hesperidin would ameliorate the radiation-induced damage. Therefore, HES may be offered as suitable radio-protector in radiotherapy patients, radiation workers and public.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
207
207
https://ijmp.mums.ac.ir/article_12824_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12824
In vivo dosimetry of intraoral stent using TLD during external photon beam radiotherapy of oral cavity
Mina
Hassani
Islamic Azad University, Science and Research Branch, Tehran
author
Seied Rabi Mehdi
Mahdavi
Radiation Biology Research Center, Department of Medical Physics, Iran University of Medical Sciences
author
Ahmad
Ameri
Department of Radiation Oncology, Shahid Beheshti University of Medical Sciences
author
Soosan
Mirmohammadrezaei
Tehran University of Medical Sciences Faculty of Dentistry
author
Alireza
Shirazi
Department of Medical Physics, Tehran University of Medical sciences
author
Alireza
Nikoofar
Department of radiation oncology, Iran University of Medical Sciences
author
text
article
2018
eng
Introduction: Individual oral stent is a mouth-opening device that used in head and neck cancer radiotherapy with the intention of decreasing radiation dose to health tissues. The
aim of this study was to check the dose delivered to both the hard palate and tongue when patient uses the stent during radiotherapy of tongue carcinoma.
Methods and materials: The intraoral stents were made for 10 patients and TLD-100 dosimeters were placed at superior and inferior parts of stent at the level of hard palate and
tongue, respectively. Then patients treated with 3DCRT technique using 6MV photons, the
data from the TLDs and treatment planning system calculations were analyzed.
Results: The results showed that the mean (±standard deviation) relative difference between
measured and calculated doses for tongue and hard palate was -4.41± 6.34, 0.57± 9.6
respectively.
Conclusion: This study demonstrated the value of thermoluminescent dosimetry as a
treatment verification method and its usefulness departmental quality assurance program.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
208
208
https://ijmp.mums.ac.ir/article_12825_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12825
Comparison of three different techniques in parotid gland tumors using three dimensional conformal radiation therapy
Farideh
Farokhi Moghadam
Medical Physics Department, Faculty of Medicine & engineering, Shahid beheshti University of Medical Sciences, Tehran, Iran. Tel: +989120570453, Email: f.farokhi93@gmail.com
author
text
article
2018
eng
Introduction:
Background: Radiotherapy of parotid tumors is achieved by different radiotherapy techniques. So they deliver the dose to organs at risk such as contralateral parotid, temporal lobe & spinal cord. The consequences of high dose to OARs are xerostomia, Temporal lobe necrosis and loss of hearing.
Purpose: The aim of this study was to compare different treatment techniques for parotid gland tumors using three different techniques to find the optimal technique which demonstrates sufficient target coverage and preserving of surrounding normal tissue at 3DCRT treatment of parotid cancer
Materials and Methods:
The CT-scans of ten parotid patients were used. The target volume and OARs were contoured and after 3D dose distribution and using of dose-volume histogram (DVH), three different plans were done and were compared: A. Ipsilateral oblique wedge photon 6MV pair with bolus
B. Photons, 3-fields AP(wedge), PA(wedge), lateral(open), C. Mixed beam: 6MV photon ipsilateral oblique wedge pair & 14Mev electron with bolus (1:4)
Results:
Target coverage was suitable for techniques B and C. Technique c showed the best homogeneity and conformity index at target volume. The dose to OARs was lower than other techniques. On other hand, technique A demonstrated ineligible homogeneity within PTV & the higher dose to OARs than other techniques.
Conclusion:
mixed beam: 6MV photon ipsilateral oblique wedge pair & 14Mev electron with bolus is an optimal treatment plan for treatment of parotid cancer patients in such way than other techniques.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
209
209
https://ijmp.mums.ac.ir/article_12826_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12826
On Presentation of Optimal Treatment Plan in Radiotherapy of Parotid Cancer: A Comparison of Nine Techniques in Three Dimensional Conformal Radiation Therapy
Farideh
Farokhi Moghadam
Medical Physics Department, Faculty of Medicine & engineering, Shahid beheshti University of Medical Sciences, Tehran, Iran. Email: F.FAROKHI93@GMAIL.COM, Tel: +98 9120570453
author
text
article
2018
eng
Introduction:
Today, radiotherapy combined with surgery in the treatment of parotid tumors widely are used specially for high grade parotid tumors. One of concern and challenge issue of radiotherapy is that the treatment of these tumors with irregular surface due to the presence of external ear and region of different physical electron density (air cavities, dense bone, soft tissue). Therefore, offering an optimal treatment plan to the desired results in terms of dose distribution factors to adequate target coverage and protect critical structures surrounding OARs is so important.
This study aimed to achieve an optimal treatment plan using low-energy electrons, as well as different modes of electrons and photons will be considered. Also the effect of bolus to achieve the optimal treatment plan is performed.
Materials and Methods:
CT of parotid patients during 2012 to 2014 is used. Twelve patients were evaluated by TPS Core plan, 3D dose distribution and using of dose-volume histogram (DVH), nine techniques were evaluated: a.6MV photons, 3-fields AP(wedge), PA(wedge), lateral(open), b. unilateral 10 Mev electrons, c. unilateral 14 Mev electrons, d. Mixed beam technique using 6MV photon and 10 Mev electron(1:4 weighting), e. Mixed beam technique using 6MV photon and 14 Mev electron(1:4 weighting), f. unilateral 10 Mev electrons with bolus (0.5 cm bolus is used), g. unilateral 14 Mev electrons with bolus (0.5 cm bolus is used), h. Mixed beam technique using 6MV photon and 10 Mev electron (1:4 weighting) with Bolus (0.5 cm bolus is used), i. Mixed beam technique using 6MV photon and 14Mev electron (1:4 weighting) with Bolus (0.5 cm bolus is used)
Results:
Using of DVH to appraise, the dose to OARs are 0 for techniques 6MV photons, (3-fields), unilateral 10 Mev electrons with and without Bolus, unilateral 14 Mev electrons with & without Bolus
Conclusion:
The highest conformal and homogeneity index and near to 1 were for 6MV photons, 3-fields, unilateral 14 Mev electrons with and without Bolus, mixed beam technique using 6MV photon and 14 Mev electron with and without Bolus.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
210
210
https://ijmp.mums.ac.ir/article_12827_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12827
Investigating The Role of Helium Bag On Electron Contamination Removal Using Beam NRC
Nahid
Chegeni
PhD in Medical Physics, Ahwaz Medical Physics Department , Ahvaz, Iran .09163534022, chegenin@gmail.com
author
Khadijeh
Hosseini
Master of Medical Physics, Ahwaz Medical Physics Department, Ahvaz, Iran. 09168565092, kh.hosseinee@gmail.com
author
text
article
2018
eng
Introduction: Several studies have discussed to the electron contamination caused by the air column between the head of linac and patient for photon beams. Since it is not possible to measure the electron contamination with practical dosimetry, the Monte Carlo technique is an appropriate and accurate choice to calculate particle flounce in radiation therapy. The purpose of this study was evaluated the effect of removing air between linac head and patient with Helium bag on electron contamination using BEAMnrc method.
Materials and Methods: The 6-MV photon beam of Varian Clinic 2100C/D was simulated using BEAMnrc code. To evaluate the role of helium bag on electron contamination removal, the photon and electron spectra were scored for 10×10 field at a source to surface distance (SSD) of 100, 120, 140, and 160 cm in the presence of the air column or helium bag. The percentage depth dose and profile calculated at depth of 10cm using DOSXYZ code.
Results: This study showed that as SSD increases, the amount of electron contamination decreases. Consequently, an increase in the height of the air column acts like a filter which it probably scatters the low-energy electrons. Replacing the helium bag in the radiation pathway led to a decrease of about 10% of electron contamination for all SSDs.
Conclusion:
The results of the study showed that in 6 MV energy, the air column has a significant contribution to produce the electron contaminant. By replacing helium bag, the skin dose of the patient may reduce over 10%.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
211
211
https://ijmp.mums.ac.ir/article_12828_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12828
Clinical Medical Physicist Training Program at Reza Radiotherapy and Oncology Centre (RROC)
Mohammad
Mohammadi
ِِDepartment of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA
School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran.
author
Hossein
Akbari Lalimi
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran.
author
Sedigheh
Khoshkharam
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran.
author
Fatemeh
Varshoee
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran.
author
text
article
2018
eng
Introduction: It has been shown that there is a strong correlation between training and improving the Radiation Oncology Medical Physicist (ROMP) and an Oncology Department Quality Management plans. The Reza Radiotherapy and Oncology Centre (RROC) beside of its development plan, has recently implemented a comprehensive in-site training plan based on ROMPs abilities and the Department requirement. This study is a comparison of the domestic plan with others developed by AAPM, CAMPEB, ACPSEM etc.
Materials and Methods: Evaluating all potential and appropriate residency Continuous Performance Development plans designed for ROMPs, a combination of all available plans were elected. At the first step, several competencies for all areas were designed. The overall time for the program is designed for two years.
Results & Conclusion: Due to the lack of a comprehensive clinical training program, RROC plan can be nominated as one of the potential plans for residency program in Iran based on the requirement and developments.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
212
212
https://ijmp.mums.ac.ir/article_12829_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12829
Evaluation of a systemic change of Superficial X-ray tube characteristics
Mohammad
Mohammadi
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
author
Kavitha
Srinivasan
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
author
Manuel
Carrillo Serrano
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
author
text
article
2018
eng
Introduction: Very low, Low and Medium X-ray machines are used extensively for Superficial Radiation Therapy mostly used for Basal Cell, Squamous Cell Carcinoma, and Melanoma skin cancers. In most of cases, Superficial X-ray Therapy (SXRT) is preferred to Electron beams generated using a linear accelerator. SXRT tube characteristics may vary with the use of the machine for a long time. This study investigates the variation of machine output characteristics acquired during machine commissioning and applied for treatment planning system.
Materials and Methods: A Gulmay D3150 Superficial Unit was used for all data collected. At the first stage, beam quality index, half Value Layer (HVL), radiation beam profiles in different depths for a range of applicator for all available applicators were collected. At the end, machine output was also compared with baseline established during the machine commissioning.
Results: Result shows that there is a systemic variation of the beam quality index up to 4.3%. Although results are found to be within tolerance, but a systemic variation of the data acquired shows that machine characteristics are modified.
Conclusion: As a systemic change of machine output is observed, based on data achieved, more detailed QA checks, annual QA program and re-commissioning of the machine for more accurate treatment is recommended.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
213
213
https://ijmp.mums.ac.ir/article_12830_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12830
Monte Carlo calculation of shielding parameters for fast neutrons in newly developed heavy concretes
Asghar
Mesbahi
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. Tel+989141193747; Fax: +98 413 3364660; Email: mesbahiiran@yahoo.com, amesbahi2010@gmail.com
author
Rezvan
Khaldari
MSc Medical Physics, Radiotherapy center, Shafa Hospital, Kerman, Iran. Tel+989132415671; Email: r.khaldari@yahoo.com
author
text
article
2018
eng
Introduction: The role of radiotherapy as a part of cancer management increases every year around the world. Thus, Radiation protection in the design of radiotherapy rooms are of great importance.
Materials and Methods: In present study using Monte Carlo method, MCNPX code, fourteen types of developed high density concretes with densities ranging from 2.45 to 5.11 g were
cm3
simulated and the neutron shielding properties of these heavy concretes with different
thickness investigated. The dosimetry parameters were calculated. The neutron shielding performance of the developed heavy concrete samples are tested by using neutron spectra of Am-Be and 18 MeV photon beam of the Varian linac. Some results of simulation were compared with available published results.
Results: The results relate to neutron shielding indicated that chemical compositions, composing elements (heavy elements such as Pb, Fe and light elements including hydrogen) and amount of these elements in concrete have important role in attenuation, capture of neutron and neutron protection.
Conclusion: It was concluded that the elemental composition and hydrogen content contribute an important rule for neutrons attenuation. Therefore when concrete is used for neutrons shielding, the water content as crystallization water in mixing ores must be taken in consideration.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
214
214
https://ijmp.mums.ac.ir/article_12831_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12831
A study on needed or unneeded ReDosimetry and Recomissioning of a linac with Add on MLC by Comparing Dosimetric Data
Navid
nateghi
MSC student in medical rediation engineering shahrood azad islamic university
author
Mohsen
layegh
senior medical physicist Omid university hospital Mashhad university of medical sciences
author
text
article
2018
eng
Introduction:
Today different uses of multileaf collimators(MLC) in different techniques of radiotherapy are common. Due to the use of this facility it is possible to have maximum radiation dose to target volumes and minimum radiation dose to critical tissues surronding treatment volumes. But there are numerouse Linear accelerators in IRAN without MLC. Because of high price of these new accelerators with MLC, maybe we have to use from Add on MLCs for our machines. The question is that do we need to redosimetry,recommissioning the linear accelerator and then revalidating our 3D Treatment Planning Software or not?
Materials and Methods:
For this purpose, first we add an Add on MLC on an Elekta Compact machine with 6 MV photon energy. Then we start dosimetry the machine by measuring dosimetry parameters like PDD in depth scan and profiles in crossline and inline scans. Also we measured scattering factors (Sc, Sp). All in reference radiotherapy fields and some most common fields.
Results:
Comparing between reference dosimetry parameters and new parameters from add on MLC in reference radiotherapy fields shows no significant deference. (pvalue<0.05)
Conclusion:
Due to these results need for redosimetry, recommissioning and consequences revalidating 3D treatment planning software will not be important for 6 MV photon energy in Elekta compact linear accelerator with Add on MLCs and will be optional.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
215
215
https://ijmp.mums.ac.ir/article_12832_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12832
Comparison the treatment time of cobalt and iridium sources in HDR brachytherapy
Mohammad Hosein
Sadeghi
MSc, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
author
Sedigheh
Sina
PhD, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
PhD, Radiation Research Center, Shiraz University, Shiraz, Iran
author
Amir
Mehdizadeh
MSc, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
author
Ali
Soleimani Meigooni
PhD, Comprehensive Cancer Centers of Nevada, Las Vegas, NV, USA
author
Reza
Faghihi
PhD, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
PhD, Radiation Research Center, Shiraz University, Shiraz, Iran
author
text
article
2018
eng
Introduction: The use of long-half-life Cobalt source instead of iridium source will be very helpful in HDR brachytherapy for treatment of cervical cancer. The aim of this study was compared the treatment time with cobalt and iridium source in brachytherapy for treatment of cervical cancer using Tandem-ovoid applicator.
Materials and Methods: In this study, 192Ir source model mHDR-v2r, and BEBIG 60Co source model Co0.A86 was used. The TG-43 formalism was used to calculate the treatment time required for both radionuclides. The reference absorbed doses to points A and B were determined from treatment data of an adult patient treated in a cancer center using Tandem- ovoid applicator, and 192Ir source. The treatment data provide us with the exact dwell positions, and times of the source, and positions of the dosimetry points. The absorbed dose to points A and B were calculated with TG-43 formalism using treatment data for iridium source, then the calculated absorbed doses were compared with absorbed doses in treatment data to determine the accuracy of using TG-43 formalism. The treatment time for iridium source is calculated by using absorbed dose in treatment data and the TG43 formalism. Then, the calculations were performed for 60Co. Considering the absorbed dose in reference points, and using the TG-43 formalism, the treatment time for cobalt source is calculated. Finally, the treatment time obtained for the two sources are compared with each other.
Results: The results of this study indicate that the treatment time for cobalt source with a specific activity of 2.131 Ci is almost the same as the treatment time for iridium source with the specific activity of 5.690 Ci. For a treatment duration of 16 minutes, the effective time window for 192Ir is about 1 to 160 days, while for 60Co this time window becomes 2000 days.
Conclusion: According to the results obtained in this study, using16 minutes treatment time60Co instead of 192Ir will be beneficial in treatment of cervical cancer patients.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
216
216
https://ijmp.mums.ac.ir/article_12833_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12833
Camera based EPID dosimetric verification of radiation treatments
Vahideh
Nazari
Medical Physics Department, Faculty of Medicine, Hamedan University of Medical Sciences, Hamedan, Iran.
author
Seied Rabi
Mahdavi
Medical Physics Department, Iran University of Medical Sciences, Tehran, Iran
author
Ahmad
Mostaar
Medical Physics and Biomedical Engineering Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Hassan
Nedaei
Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
author
Mohammad Amin
Mosleh Shirazi
Medical Physics Department, Shiraz University of Medical Sciences, Shiraz, Iran
author
Golbarg
esmailie
Medical Physics Department, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Tumor control and treatment quality depend on accuracy of delivered dose. Various methods have been studied for treatment dosimetry verification. Among these methods, the use of electronic portal imaging device (EPID) is highly considered. Many efforts are underway to improve the results of this context.
Materials and Methods:
In this study, a new method for pretreatment dose verification is reported using the transmitted signal of a camera based EPID. Lateral scatter within imager has been considered as field size dependent additive operation. Lateral scatter description within the imager were obtained from measurements with a 2D array ionization chambers for a set of different field sizes. The water-equivalent thickness of phantom material was defined for dose reconstruction, by means of the treatment planning system, according to the patient's data in CT scans along the beam central axis.
Results:
The method was tested for pretreatment verification of 3D conformal prostate cancer treatment plans. There are no significant differences between the EPID and ionization chamber responses (P value = 0.37).
Conclusion:
This study proposes a practical method with easier and less calculations in comparison to the deconvolution approaches that can be applied for overall dosimetric assessments of treatments in every fraction.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
217
217
https://ijmp.mums.ac.ir/article_12840_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12840
Comparison of ScintSim1 and Geant4 Monte Carlo simulation codes for optical photon transport in thick segmented scintillator arrays
Sahar
Ranjbar
Department of Medical Physics and Engineering, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad Amin
Mosleh-Shirazi
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Physics Unit, Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Somayeh
Gholami
Radiotherapy Oncology and Radiobiology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
Sareh
Karbasi
Physics Unit, Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Zinat
Zarrini-Monfared
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Arrays of segmented scintillation crystals are useful in megavoltage x-ray imaging detectors for image-guided radiotherapy. Most previous theoretical studies on these detectors have modelled only ionizing-radiation transport. Scintillation light also affects detector performance. ScintSim1, our previously reported optical Monte Carlo code for such detectors, includes the main optical processes of interest. Here, we benchmarked ScintSim1 against the more complex and extensive Geant4 optical Monte Carlo toolkit. We aimed to assess the importance of some simplifications made in ScintSim1 and gain further insight into the more relevant optical processes
Materials and Methods:
We used Geant4 (version 9.6. p02) in this study. As the aim of this study was to compare the simulation of optical photons in the two codes, dependence of the simulation results on x- ray and electron interactions had to be excluded. To compare the two models correctly, they had to have the same inputs. So, in both models, an equal number of light photons were generated at identical points, obtained from previously computed depth-dose distributions resulting from X-ray and electron interactions. We first performed various tests to check proper implementation of the Geant4 code then various optical results (such as numbers and distributions of incidences, absorption and reflection) were compared. In the second part of the study, Geant4 was used for coupled simulation of ionizing radiation (x-rays and electrons) and optical photon transport in the scintillator with a slit to obtain the ionizing- radiation-only line spread function (LSF) of the energy deposited in the elements and the number of optical photons incident on an underlying screen (‘full simulation’ including ionizing radiation and optical photons) for each case. A composite LSF was then calculated and compared with the corresponding optical results obtained by using ScinSim1
Results:
The differences between the optical outputs of the two codes ranged between 0.1% and 1.7%. The full-width-at-half-maximum values of the LSF for energy deposited and total (ionizing + light) normalized LSFs from the two codes differed by only 0.01 mm and 0.1 mm, respectively. Using the same computer, the run time required to launch and simulate 108 optical photon histories (without any prior ionizing radiation transport) was 16 minutes in ScintSim1 and 421 minutes in Geant4.
Conclusion:
These results show a close agreement between the outputs of the two models for the studied conditions and suggest that the optical processes not modelled in ScintSim1 have little effect on the results required for detector optimization in megavoltage imaging using an array of segmented scintillation crystals. The model simplifications in ScintSim1 offer substantial run-time reductions if computational time-reduction methods are not used. Nonetheless, the developed Geant4 model is a powerful tool for further detector design parameter optimization.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
218
218
https://ijmp.mums.ac.ir/article_12841_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12841
Exploring the Possibility of Estimating Degree of Glioma Tumors by Measuring Apparent Diffusion Coefficient
Farideh
Momeni
Medical Physics and Medical Engineering Department, School of Medicine, Shiraz University of Medical Sciences; Shiraz, Iran
author
Zahra
Farshidfar
Radiology Technology Department, School of Para Medicine, Shiraz University of Medical Sciences; Shiraz, Iran
author
Nastaran
Taleinezhad
Radiology Technology Department, Chamran Hospital, Shiraz University of Medical Sciences; Shiraz, Iran
author
Leila
Ansari
Medical Physics and Medical Engineering Department, School of Medicine, Shiraz University of Medical Sciences; Shiraz, Iran
author
Ali
RazmKon
Neurosurgery Department, Shiraz University of Medical Sciences; Shiraz, Iran
author
Ali Reza
Mehdizadeh
Medical Physics and Medical Engineering Department, School of Medicine, Shiraz University of Medical Sciences; Shiraz, Iran
author
text
article
2018
eng
Introduction: Most common glioma tumors are tumors of the central nervous system (CNS) which are the cause of about 40 to 50 percent of brain tumors. This type of cancer includes 2 to 3 percent of cancers in the world. Conventional MRI is powerless in the detection and differentiation of benign and malignant tumors. In this case, diffusion weighted imaging (DWI) can create contrast between normal and abnormal tissues and in terms of the emissions, benign and malignant tumors being detected. The apparent diffusion coefficient (ADC) only depends on the extent (mass), temperature and viscosity of the tissue molecules. In this study, we measured apparent diffusion coefficient of the tumors and quantified the ammount of the ADC values and recognized benign or malignant tumors without biopsy.
Materials and Methods: We used diffusion weighted images and pathologic findings of 56 patients with glioma tumors, 28 patients with benign and 28 cases with malignant tumors. DicomWorks software was used to calculate apparent diffusion coefficient of tumor and also by use of ROC curve, we introduced an optimized cut off for this type of tumor.
Results: In this study we have measured the amount of ADC of four regions. Diagnostic threshold for ADC of tumor center (ADC1) was found to be equal to 1.12 × 10-3 mm2/s, for which the sensitivity and specificity were equal to 1 and 0.96, respectively. The resulting diagnostic threshold for tumor edema areas (ADC2), is 1.15 × 10-3 mm²/s. The diagnostic thresholds of sensitivity and specificity are equal to 0.75 and 0.64, respectively. The diagnostic threshold for ADC3 (Areas between the Tumor and Normal Tissue) values was also gained. Numerical threshold was equal to 0.84 × 10-3 mm²/s; both sensitivity and specificity are equal to 0.5.
Conclusion: According to the different characteristics of the release of water molecules in different tissues, DWI and ADC values can help to diagnose and determine the severity of the tumor. By determining cut off for apparent diffusion coefficient of the tumor prior to surgery, we can diognose that is benign tumor or malignant one; so that tumors with ADC values of higher than 1.12*10-3 mm2/s are benign and tumors with ADC values lower than this ammount are malignant.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
219
219
https://ijmp.mums.ac.ir/article_12842_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12842
Automatic Classification of Benign And Malignant Liver Tumors In Ultrasound Images
Milad
Zeinali Kermani
MSc, Shafa Hospital, Kerman, Iran;
author
Akbar
Gharbali
Department of Medical Physics, Faculty of Medicine, UUMS, Urmia, Iran
author
Afshin
Mohammadi
Dept. of Radiology, Faculty of Medicine, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, Iran
author
text
article
2018
eng
Introduction: Differentiation of benign and malignant liver tumors is very important for finding appropriate treatment procedure. Human eyes sometime are not able to diagnose the type of liver tumor. Texture analysis is considered as a suitable method to increase the diagnostic power of medical images. In this study texture analysis is employed in order to classification of benign and malignant liver tumors in ultrasound images.
Materials and Methods: Our study was performed on 38 patients (25 malignant and 13benign). After selection of proper ROI, about 270 parameters were extracted from each ROI. Fisher algorithm was employed for selection of the best discriminating features. Three analysis methods (PCA, LDA and NDA) were performed at the last stage. Statistical analysis of data was performed by Receiver Operating Characteristic (ROC).
Results: The result of our study was very plausive. The best discrimination result was belong to NDA with sensitivity and specificity of 100%. PCA and LDA also had good results (sensitivity of 97% and 98% respectively).
Conclusion: This study show that texture analysis is able to classify benign and malignant liver tumors in US images with the high performance quality. Therefore, texture analysis may be a useful method for classification of benign and malignant liver tumors.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
220
220
https://ijmp.mums.ac.ir/article_12843_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12843
Usefulness of nanoparticles to making shield and protection of sensitive organs in chest CT scan test
Mohammad
Yousefi Sooteh
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Student research committee, Tabriz University of Medical Sciences, Tabriz, East Azerbaijan, Iran
author
Parinaz
Mehnati
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Reza
Malekzadeh
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
text
article
2018
eng
Introduction: Recently, the use of nanoparticles has increased for many purpose in medicine. One of these is using the nano particles in shields structure to protect sensitive organs such as breast which placed inside the field of chest CT scan and receives high dose. The aim of this study was the use of nano Bi2O3 to making shield for protection breast in chest CT examination and evaluating their image quality.
Method and Materials: The nano Bi2O3 powder was used for create shield at 1mm thickness. The 6-slice CT scan system and PMMA phantom were used for dose measurement. Dose measured once in present of the shield and once in absent of the shield. Also the image quality was measured.
Results: Reference average dose was 8.6 mGy in chest CT scan test which changed to 7.4 mGy when Bi2O3 shield was placed on the phantom. Also CT number and noise were raised from 121 HU and 24 to 126 HU and 28.
Conclusion: On the base of results, the Bi2O3 nano particles have enough potential for radiation protection and using as a shield for reducing of breast dose in CT scans with acceptable image.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
221
221
https://ijmp.mums.ac.ir/article_12845_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12845
Evaluation of deformable image registration in HDR gynecological brachytherapy
Reza
Mohammadi
Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran
Medical Image and Signal Processing Research Core, Iran University of Medical Sciences, Tehran, Iran
author
Ramin
Jaberi
Department of Radiotherapy, Cancer Institute, Tehran University of Medical Science, Tehran, Iran
author
Reza
Reiazi
Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran
Medical Image and Signal Processing Research Core, Iran University of Medical Sciences, Tehran, Iran
author
Seyed Rabee
Mahdavi
Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: In brachytherapy, as in external radiotherapy, image-guidance plays an important role. For GYN treatments it is standard to acquire at least CT images and preferably MR images prior to each treatment and to calculate the dose of the day on each set of images. Then, the dose to the target and to the organs at risk (OAR) is calculated with worst case scenario from ICRU recommendation that propose add maximum doses to the volume of 2cc of every organ (D2cc) from every session. Especially for the OAR, it makes the safe conservative assumption that the same part of the OAR always receives the highest dose. The dose calculated this way often limits the prescription dose or the target coverage. In this work, we propose to investigate an alternative method to assess the cumulative dose for an HDR GYN treatment course; the use of image deformation software to track the deformations of the OAR from one fraction to the next.
Materials and Methods: Thirty patients with locally advanced cervical cancer who had been treated by external beam radiotherapy (EBRT) and three to four fractions of HDR brachytherapy (HDR-BT) were introduced to this study. Intensity-based free form deformation algorithm has been used as the primary DIR techniques using MIM software. In the dose accumulationn stage, total doses of rectum and bladder from all brachytherapy fractions have been integrated by deformable image registration techniques.
Results: The DICE, jaccard, MDA and HD indexes of deformable registration for bladder and rectum were (0.94±0.03), (0.89±0.06), (0.83±0.3), (9.85±3.8) and (0.86±0.05), (0.78±0.07),
(1.46±0.7), (14.4±0.1) respectively compared to rigid registration for bladder and rectum that were (0.74±0.07), (0.61±0.07), (4.2±2.3), (18.73±8.6) and (0.59±0.13), (0.43±0.11),
(5.01±1.7), (23.4±1.1) respectively. Dose accumulation of D2cc values were (5.1±2,3)% and (2.7±1.1)% lower for the bladder and rectum respectively compared to adding D2cc of each fractions.
Conclusion: Using deformable image registration, based on image intensity, allows to accumulate the dose from different brachytherapy fractions. The results from our study indicate that it is feasible to utilize deformable image registration for dose accumulation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
222
222
https://ijmp.mums.ac.ir/article_12846_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12846
Evaluation of the gray level in CBCT systems and its relationship with HU in CT Scanners
Ahdiyeh
Aghaz
Nuclear Science and Technology Research Institute, Tehran, Iran, mkardan@aeoi.org.ir.
author
Mohammad Reza
Kardan
Nuclear Science and Technology Research Institute, Tehran, Iran,
author
Mohammad Reza
Deevband
Department of Medical Physics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Bahador
Bahadorzadeh
Nuclear Engineering Department, Shiraz University, Shiraz, Iran.
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
author
Yaser
Kasesaz
Nuclear Science and Technology Research Institute, Tehran, Iran,
author
Hossein
Ghadiri
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction:
Cone-beam CT (CBCT) is an imaging system which offers three-dimensional (3D), multiplanar images and has many advantages over computed tomography (CT) including shorter acquisition times for the resolution desired in dentistry, lower radiation dose to the patient, reasonable price and higher spatial resolution but CBCT scanners are unable to display actual Hounsfield units (HU) similar to medical CT. In CT scan, to show the image that represents the density of the tissue Hounsfield Unit is proportional to the degree of x-ray attenuation and it is allocated to each pixel. In CBCT systems displayed gray levels are arbitrary and so variable, so the derived density provided less than meaningful data and the ability to assess the density or quality of bone is limited. The purpose of the present study was to present a clinical study demonstrating a method to derive Hounsfield units from gray levels in cone beam CT (CBCT).
Materials and Methods:
For the evaluation of CBCT gray values, a new versatile quality control tool of dental Cone- Beam CT, Pro-Dent CT mk II phantom, which consists of a main PMMA cylinder that houses modules with different test objects was used. Four CBCT devices were used for the scanning of the phantom: CS8100, CS9300(Carestream Health, New York, NY), New Tom GIANO (Quantitative Radiology, Verona, Italy), Vatech Pax-i3D (Hwaseong-si, Gyeonggi-do, Korea). The reconstructed data were exported as Digital Imaging and Communications in Medicine (DICOM) and analyzed with On Demand 3DH by Cybermed, Seoul, Korea and ImageJ as an image processing toolkit. The relationship between gray levels and linear attenuation coefficients in various kV and mA was investigated.
Results:
The results indicated a strong linear relationship between the gray scales in CBCT and HU in CT using the standard definition HU = (µmaterial – µwater)/(µwater) × 1000. This made it possible to calculate Hounsfield units from the measured gray levels. Uncertainty in determining effective energies for each of CBCT systems resulted in unrealistic effective energies and significant variability of calculated CT numbers. Linear regression (0.802<R2<0.981) from gray levels directly to Hounsfield units at specified energies resulted in greater consistency. Conclusion:
Considering the fact that CBCT gray levels are inaccurate to rely upon for decisions on implant placement. HU can be derived from the gray levels in dental CBCT scanners using linear attenuation coefficients as an intermediate step. This study presented a method to convert gray levels in CBCT imaging into meaningful HU. Establishment of meaningful HU for CBCT will open new possibilities for clinicians in implant planning, diagnosis, surgical interventions, treatment planning, 2D and 3D reconstruction of images.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
223
223
https://ijmp.mums.ac.ir/article_12847_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12847
Comparison of two different methods for CTDIw calculation in CBCT systems
Ahdiyeh
Aghaz
Nuclear Science and Technology Research Institute, Tehran, Iran.
author
Mohammad Reza
Kardan
Nuclear Science and Technology Research Institute, Tehran, Iran.
author
Mohammad Reza
Deevband
Department of Medical Physics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran, mdeevband@sbmu.ac.ir.
author
Bahador
Bahadorzadeh
Nuclear Engineering Department, Shiraz University, Shiraz, Iran.
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Dental Cone beam CT (CBCT) is an imaging modality which has emerged as a 3D imaging modality of choice for osseous structures in the maxillofacial region. With increased usage of CBCT imaging for diagnosis and treatment planning, it is imperative that stringent dose assessments must be performed for dose estimation to safeguard both the patients and operating staff. In CT scanners, CT dose index (CTDI) measurements are part of standardized quality assurance protocols that uses a 10-cm pencil ionization chamber to approximate dose
output for a single axial scan. The weighted CTDI (CTDIw = 1 CTDIc + 2 CTDIp) is used for
3 3
CTDI calculations. The SEDENTEXCT project introduces a type of dose index calculation method
for dental CBCT systems, that is calculating the dose measurements from the central and the peripheral positions to represent a dose index (Sedentex-DI2). In this study we utilize the same method to calculate CTDIw that is used in CT scanners and compare with the Sedentex-DI2 method as shown in: D =Dc+Dp to provide insights for developing a robust dose
periphery 2
assessment in dental CBCT systems.
Materials and Methods:
The CTDI head phantom of PMMA with a diameter of 16 cm and 15 cm long and 10-cm cylindrical pencil-shaped air ionization chamber for CTDI measurements were used in this study. Two different CBCT machines scanned the phantom: CS9300 (Carestream Health, New York, NY), ProMax 3D mid (Planmeca Oy, Helsinki, Finland) and three FOVs was used in both of them. Scans in both of the systems were repeated another two times at the same exposure parameters to check the reproducibility of the measured dose. All dose measurements at off- axis FOVs were performed.
Results:
The CTDIw from SEDENTEXCT (DI2) method was 3.1245 mGy, 3.2296 mGy and 1.5447 mGy for (ø8×5, ø20×10 and of ø4×5 cm2 FOVs, respectively) in ProMax 3D mid system. In CS9300 system these measurements were 3.104 mGy, 3.942 mGy and 6.648 Gy for FOVs of (ø5×5, ø10×5 and ø10×10 cm2, respectively). But calculated CTDIw by standard CTDI method was 2.923 mGy, 3.308 mGy and 1.763 mGy for (ø8×5, ø20×10 and ø4×5 cm2 FOVs, respectively) in ProMax 3D mid system and in CS9300 system these measurements were 2.969 mGy, 3.794 mGy and 6.502 Gy for FOVs of (ø5×5, ø10×5 and ø10×10 cm2, respectively). Conclusion: The results show that the calculated CTDIw values were very close to each other in both the standard and Sedentex-DI2 methods and did not differ significantly. So, it seems that both methods can be used to measure the dose index in CBCT systems. However, it should be noted that the dose values in the peripheral holes indicate that there is no symmetric distribution for the dose in these systems, and therefore CTDI measurement methods cannot be applied to all different FOVs at different central and off-axis positions. We should introduce a valid dose index based on the dose distribution in each mode of the FOV for each system.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
224
224
https://ijmp.mums.ac.ir/article_12848_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12848
The effect of Rectal Retractor, a rectal protector on rectal dose in radical prostate radiotherapy
Hamed
Ghaffari
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Bahram
Mofid
Department of Radiation Oncology, Shohada-e-Tajrish Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Seyed Rabi
Mahdavi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Aram
Rostami
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: The close proximity of the rectum tissue to the prostate gland results in rectal toxicity during prostate radiotherapy. Rectal Retractor (RR) is a rectal displacement technique that inserts into the rectum, as a result, the lateral and dorsal part of the rectal wall push away from high dose areas. The aim of this study was to investigate the dosimetric consequences and rectal tissue sparing effect of RR during prostate three-dimensional radiotherapy (3DCRT).
Materials and Methods: In 15 patients with localized prostate cancer, two planning CT- scans were carried out: without and with RR. The prostate and seminal vesicles plus 5 mm margin were considered as planning target volume (PTV). All patients were treated using 3DCRT with prescription dose of 80 Gy. The inter-fraction setup errors were corrected by electronic portal imaging device (EPID) and fiducial gold markers. Dose volume histograms of the rectum were compared in plan without and with RR.
Results: All patients well tolerated RR during first 20-25 fractions. Using RR, mean dose to the rectum was 39 cGy (P <0.001) lower per fraction. Comparison between plan without and with RR indicated that RR resulted in a mean reduction of 57.3%, 63.8%, 71.9% and 72.8% in rectal V50Gy, V60Gy, V70Gy and V75Gy, respectively (P <0.001).
Conclusion: The retraction of the rectum is associated with a significant lower dose to the rectum. This may lead to reduction of the rectal toxicity during prostate radiotherapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
225
225
https://ijmp.mums.ac.ir/article_12855_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12855
Treatment couch positioning uncertainties using an EPID-based method
Azam
Afzalifar
Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran.
author
Ali Asghar
Mowlavi
Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran.
ICTP, Associate federation Scheme, Medical Physics Field, Trieste, Italy.
author
Mohammad
Mohammadi
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
Sara
Abdollahi
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran.
author
text
article
2018
eng
Introduction: The accuracy of patient positioning plays an important role for radiotherapy tasks. Short and automated Quality Assurance (QA) programs are becoming one of the challenging tasks in Radiotherapy. The current study, investigates the accuracy of treatment couch positioning with four degrees of freedom (4DoF) using a fast and accurate method based on an image acquired using an electronic portal imaging device (EPID).
Materials and Methods: A Siemens medical linear accelerator equipped with an a-Si EPID was used to capture portal images. An accurate EPID QA phantom (PTW EPID QC Phantom®) and a proper in-house algorithm were used. The phantom has different sections to assess EPID image quality. Preliminary tests including Mechanical performance of the EPID positioning, EPID sensitivity and the code response from image processing point of view were investigated through several deviations deliberately created to evaluate translational and rotational displacements of treatment couch. Loading effect on treatment couch was also investigated.
Results: The results of EPID preliminary tests and in-house code reliability were within tolerances expected. The mean deviations of tests for (4DoF) treatment couch were 0.25°±0.10˚, 0.428±0.112 mm, 0.428±0.112 mm and 0.286±0.112 mm for rotational, longitudinal, lateral and vertical shifts, respectively. The results of incline caused by a 130kg loading on the couch showed that the proposed method is a reliable and fast to find the uncertainties occurred for treatment couch positioning.
Conclusion: As a part of linac QA program, treatment couch tests including translational and rotational motions under unloaded/loaded conditions were performed. The corresponding errors for table positioning including minimum detectable rotational and translational displacements, and couch sagging effect under loaded conditions were evaluated using an EPID. Creating one major test for the whole assessments for couch checks, fast and accurate and no labour intensive procedure, and electronic portal image instead of film and other
imagers can be addressed as advantages of the method proposed.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
226
226
https://ijmp.mums.ac.ir/article_12856_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12856
Analytical investigation of the practical range and deflection of megavoltage electron beam in the water phantom with the presence of magnetic field
Mohammad Javad
Tahmasebi Birgani
Ph. D, Radiation Therapy and Medical Physics Department, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences
author
Nahid
Chegeni
Ph. D, Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
Marziyeh
Tahmasbi
Ph. D, Department of Radiology Technology, Paramedicine Faculty, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
Mansour
Zabih Zade
Ph. D, Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
text
article
2018
eng
Introduction: Integrated radiation therapy - MRI systems are capable of delivering high doses to the target tissues near sensitive organs and achieve better therapeutic results; however, the Applied magnetic fields for imaging, can influence the charged path, change the penetration depth and deflect the particles, laterally, leading to dose distribution variations. Therefore, investigating the effects of magnetic field on charged particles is important in treatment planning. Therefore, this study aimed to calculate the effects of magnetic field on the range and lateral deflection electrons to determine analytic relations for treatment planning of electron therapy integrated with MRI-systems. Also, these relations will be used to active condensing of charged particle dose in target volume.
Materials and methods: An analytical survey based on electron practical range and energy, was done. The penetration depth and lateral deflection of electrons with therapeutic energy ranges in the presence of uniform magnetic field were calculated, analytically. Calculations were done with Mathematica software version 7.0 and MATLAB 7.0 was applied to plot curves and curve fittings.
Results: A cubic polynomial with linear coefficients and a power model with constant power model were applied to illustrate lateral deflection and practical range of electrons as a function of initial energy and magnetic field intensity. Electrons go to spiral path with increasing magnetic field intensity about 1.25 Tesla.
Conclusion: The proposed analytical approach can calculate the lateral deflection and penetration depth of electrons in the water phantom in the presence of magnetic field of any intensities fast and accurately. This method can be used to calculate dose variations in integrated radiation therapy- MRI imaging systems for treatment planning and research proposes. Due to fast calculations of the presented analytical method in comparison with Monte Carlo based approaches, the calculations time in treatment systems will be decreased.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
227
227
https://ijmp.mums.ac.ir/article_12857_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12857
A New Theranostic System Based on Gd2O3 NPs coated Polycyclodextrin Functionalized Glucose for Molecular Magnetic Resonance Imaging (MMRI).
Tohid
Mortezazadeh
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
Nader
Riahi Alam
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
Mehdi
Khoobi
Pharmaceutical Sciences Research Center, The institute of Pharmaceutical Sciences,
Department of Pharmaceutical Biomaterials, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
author
Elham
Gholibegloo
Pharmaceutical Sciences Research Center, The institute of Pharmaceutical Sciences, Tehran University of Medical Sciences, Tehran 1417614411, Iran
author
Sadegh
Dehghani
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
Soheila
Haghgoo
Pharmaceutical Department, Food and Drug Laboratory Research Center, Food and Drug Organization (FDO), Ministry of Health, Imam St., Valiasr Cross, 1113615911 Tehran, Iran
author
text
article
2018
eng
Introduction: Recent advances in nanoscience and biomedicine have attracted tremendous attention over the past decade to design and construct multifunctional nanoparticles that combine targeting, therapeutic, and diagnostic functions with a single platform to overcome the problems of conventional techniques for diagnosis and therapy with minimal toxicity.
Materials and Methods: In this essay, we examine the potential advantages of gadolinium oxide nanoparticles (Gd2O3 NPs) as a positive contrast agent in MRI coated with β- cyclodextrin (CD)-based polyester and targeted by Glucose (Glu) as platform nanocomplex for theranostics. Doxorubicin (DOX) was loaded into this nanocarrire (Gd2O3@PCD-Glu) and their properties including loading efficiency and capacity were investigated. The toxicity was evaluated by MTT and hemolysis assay was employed to evaluate the cytotoxicity of the nanocomplexe against normal and cancerous cells and human red blood cells (HRBCs)
Results: A prolonged release of DOX from nanocomplexe was observed. The DOX release revealed a pH-sensitive mechanism. This drug delivery system showed more toxicity against cancer cells in compare to normal ones. The results of in vitro magnetic resonance imaging (MRI) showed that this nanocarrier could be used as a positive contrast agent in MRI. The relaxivity of Gd2O3@PCD-Glu was more than Gd2O3, and Dotarem in the presence of MDA- MB-231 as glucose receptor-positive cells under T1-weighted imaging mode showing the great effect targeted delivery. The in vivo analysis indicated that the contrast to noise ratio (CNR) of tumor in mice increased after injection of Gd2O3@PCD-Glucose up to 6.98±0.97 under T1-weighted imaging mode and gradually reduced to 6.46±1.3 after 1h respectively. While, CNR increased up to 5.81±1.3 after injection of Dotarem and reduced sharply down to 2.3±1.11 within 1h.
Conclusion: The results indicate the potential of Gd2O3@PCD-Glu to serve as a novel nano-targeted theranostics contrast agent in Molecular Magnetic Resonance Imaging (MMRI).
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
228
228
https://ijmp.mums.ac.ir/article_12858_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12858
Does short-term exposure to Wi-Fi waves affect the cognitive functions of the mind?
Mohammad Amin
Hosseini
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
author
Atefeh
Hosseini
Department of Occupational Health, School of Health and Nutrition, Shiraz University of Medical Science, Shiraz, Iran
author
Samaneh
Jarideh
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
author
Hossein
Argasi
Research Center Consultation (RCC), Shiraz University of Medical Sciences, Shiraz, Iran
author
Fatemeh
Shekoohi-Shooli
Institute for Advanced Biomedical Technologies, Chieti, Italy
author
Shaharm
Taeb
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
author
Masoud
Haghani
Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction: In recent years, we have seen a tremendous growth in communications devices, such as mobiles and tablets. Also, the appeal to connect to the Internet through wireless systems has increased significantly. Given these changes in everyday life, the approach to cognitive works and problem-solving and decision-making in a complex system that has become increasingly important. Hence, the aim of this study was to investigate the effect of short-term exposure to Wi-Fi waves on cognitive functions of the mind.
Materials and Methods: After obtaining permission from the local ethic committee of Shiraz University of Medical Sciences (IR.SUMS.REC.1394.72), 45 male and female students volunteered to participate in this study. The present study was a quasi-experimental research in which pre-test and post-test was used without a control group. To this end, participants were exposed to irradiation in two seasons: Sham (without the presence of waves) and exposure (with irradiation). During each season, participants were exposed to radiation in a direction perpendicular to their head and at a distance of 1.5 meters away from the antenna of the Wi-Fi router (D- Link, China). Upon completion, a couple of tests, such as short-term memory, reaction time, and reasoning were performed at the end of each session. Also, the electric field strength and power density of the waves were calculated at the mentioned distance.
Results: The statistical analysis of the data showed that there was no statistically significant difference in the mean scores for the participants’ short-term memory, reaction time, and reasoning between the sham and exposure group. On the other hand, the calculated values of the electric field strength and power density of the waves were within the range permitted by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
Conclusion: With the development of communication devices, concerns about their effects on human health including cognitive function of the mind are increasing. Our findings suggested that short-term exposure to Wi-Fi waves has no significant effect on the cognitive function of the mind, and this can reduce concerns in this regard.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
229
229
https://ijmp.mums.ac.ir/article_12859_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12859
Mathematical model creation for Reducing damages in basketball players
Aida
Valizadeh
Medical student of Shahid Beheshti University of Medical science, Tehran, Iran, +989144943345, aydavlz@gmail.com
author
Narmin
Ghanizadeh Hesar
Phd assistant professor of physiology and corrective exercise department, sport science faculty, Urmia University, Urmia, Iran,+98914 341 2193, n_hesar@yahoo.com
author
Zahra
Sadehdel Fadafan
MA sport injury & corrective exercise of urmia University, Urmia, Iran,+989353592193,z.sadehdel@gmail.com
author
text
article
2018
eng
Introduction: Hand and wrist stability are critical for optimal upper extremity function. Instability occurs when injury or a pathological condition alters balance, typically in the
basketball players and handball players. Injury also can occur whenever the ligaments are subjected to tensile forces that exceed their physiological capacities. For example, thumb is stable in extension when ulnar collateral ligament sprain or tear and gamekeepers thumb injury happen but it appears to be unstable inflexion. The goal was to decrease this injury to a region.
Materials and Methods:
Precise hand positioning on 5 Basketball is drawn for guides to teach proper shooting technique by using Morley theorem proof results (figure1). Lemma: if points ź. y. z. ý follow conditions: zý = zy = yź. ŷzý = ẑ́yz = π − 2α > π then will be located on a
circle. Circleaýzyź is as a Basketball and points are as Head of distal phalanges. If angle size between finger number 1 and finger number 2 and finger number 5 equals3α , this size between finger number 2 and finger number 3 and between finger number 3 and finger number 4 equals2α , It is same for between finger number 4 and finger number 5; as a result, force that comes from the Basketball brings the least damage in the fingers and thumb.
Results: The alpha angle size is different in Athletes; but according to the theorem, it must be less thanπ. Our Studies have found alpha angle normal size (about15°) and relation between alpha angle size and Distance between fingers in basketball players follow: sin (π − α) +3 1
sin(π−α)3. When the alpha equals 15, the equation is 2.12 cm, by considering this result shooting range increase and damages is in lowest point.
Conclusion Results also can be used in evaluations. ligament laxity maybe reduced by using Mathematical model.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
230
230
https://ijmp.mums.ac.ir/article_12860_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12860
Assessment of a cluster of gold nanoparticles effect on cell absorbed dose using the Geant4 toolkit
Arezoo
Kazemzadeh
MSc of medical physics, Department of Medical Physics, Faculty of Paramedicine, Kashan University of Medical Sciences, Kashan, Iran, Email: kazemzadeh-a @kaums.ac.ir
author
Habiballah
Moradi
Assistant professor, Department of Medical Physics, Faculty of Paramedicine, Kashan University of Medical Sciences, Kashan, Iran
author
text
article
2018
eng
Introduction: Radiotherapy plays a vital role in cancer treatment. To establish a new potency in radiosensitize tumor cells, delivery of High-Z materials is offered. To date, several simulation geometries have been applied to define simulation sets. The clustering of nanoparticles (NPs) within the cells is a prominent parameter usually ignored in simulation studies. Materials and Methods: The simplified geometry of the cell was simulated. The modeled nucleus was a cube of 13 ×10×5 µm3 corresponding to the box of the nucleus in WholeNuclearDNA which was filled with liquid water. Nanoparticles were arranged in an orderly manner next to the box of modeled nucleus. To define the impacts of different energies and sources on dose enhancement ratio (DER) in the target, mono-energetic photon and electron beams within keV to MeV range spread spatially from a source point. Also, this proposed model was to assess the optimum features of GNPs structure parameters, like the size. Results: The largest volumes of DER of photons were about 40 and 108 fold in the nucleus and cytoplasm when GNPs were consumed, and the same was 2.4 and 1.12 for electron beams in cellular regions, respectively. It was demonstrated that the linear correlation between DER and GNPs size was for 40 keV photons, while there was no striking change for 900 keV electron beam when GNPs size changes. Conclusion: It is concluded that GNPs in combination with the electron beams are less efficient compared to the low energy photons. Larger GNPs do not show any preference when irradiated through electron beams as much as they do with photons.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
231
231
https://ijmp.mums.ac.ir/article_12861_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12861
Proof of Symmetric Dose Distribution in Mammosite Applicator in Breast Brachytherapy with MCNP Simulation
Fatemeh
Mahdavi
M.Sc. of Medical Radiation Engineering, of Science and Research University of Tehran
author
Alireza
Shirazi Hosseini Dokht
Professor of Physics and Medical Engineering Department of University of Tehran
author
Mahdi
Sadeghi
Professor of Medical Physics Department of Medical University of Iran
author
text
article
2018
eng
Introduction: In brachytherapy treatments, high-dose sources are used in interstitial placement. In this paper, the modeling of a common breast cancer treatment applicator called MammoSite is done by the Monte Carlo simulation code. Then, to study and calculate the amount of doses in the breast and the dose rate of the organs at risk of radiation, including: lungs, ribs and skin, Then the absorbed dose ratio is calculated in the target volume to the treated chest.
Materials and Methods: The MCNPX code: is the based on the Monte Carlo method. The code, with input file information and the use of the cross-section library, solves the problem and produces results in an output file.
MIRD phantom: To calculate the dose, a model of the human body is required as a phantom. All organs of the human body are characterized by a detailed description for the calculation of the absorbed dose in this phantom.
Mammosite applicator: This device has a catheter that can be attached to the high dose rate after loading machine that connect to the source. The end of catheter is surrounded by a balloon. The most common size of this balloon is 4-5 cm and 5-6 cm, which has a volume between 34-113 cm cubic meters.
Results: As expected, the absorbed dose in the target volume and the treated breast was the highest and after that the lung received the same significant dose. That is, the highest doses of the target or tumor volume and the lower doses of the surrounding organs are reached. Healthy organs have received around high dose ratios. When the right breast was treated, the right lungs, ribs, and skin had the highest dose ratios relative to the dose received by the tumor and when the left breast was treated, the left lung, ribs and skin had the highest dose ratios relative to the dose received by the tumor.
Conclusion: Given that in Iran, not only the mammosite applicator but also the treatment planning system for brachytherapy is not available. The inability of the MammoSite applicator in the asymmetric dose distribution cannot be shown. However, due to the absorption dose ratio of breast tissue to absorbed dose by the target volume in the right breast, which is numerically equal to 1.035, And the absorbed dose rate of the left breast tissue to the absorbed dose by the target volume, which is a number equal to 1.033, both of which are approximately equal, It can be concluded that the same dose that reached the tumor tissue is about the same size as the healthy tissue of the treated breast. This represents a symmetric dose and proves that the MammoSite applicator is incapable of asymmetric dispensing.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
232
232
https://ijmp.mums.ac.ir/article_12862_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12862
Gold nanoparticle-induced sonosensitization enhances the antitumor activity of ultrasound in colon tumor-bearing mice
Jaber
Beik
Master of Sciences, Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
Ali
Shakeri-Zadeh
PhD, Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
text
article
2018
eng
Introduction:
Light-driven cancer therapy strategies (e.g. photodynamic therapy and photothermal therapy) have undergone remarkable progress in recent years, but they still suffer from a serious drawback of limited penetration depth of light in tissue. As a non-invasive and non- ionizing radiation, ultrasound can be focused remotely, transferring acoustic energy deep in the body, thereby addressing the penetration depth barrier of light. In cancer therapy, the effectiveness of ultrasound can be enhanced by utilizing nanomaterials that exhibit sonosensitizing properties called as nanosonosensitizers. The gold nanoparticle (AuNP) has been recently presented as a potent nanosonosensitizer with the potential to simultaneously enhance both the thermal and mechanical interactions of ultrasound with the tissue of the human body. Accordingly, this paper attempts to evaluate the in vivo antitumor efficiency of ultrasound in combination with AuNP.
Materials and Methods:
BALB/c mice bearing CT26 colorectal tumor model were intraperitoneally injected with AuNPs and then subjected to ultrasound irradiation (1 MHz; 2 W/cm2; 10 min) for three sessions.
Results:
The tumors were thoroughly eradicated and the mice appeared healthy over 21 days of study span without the evidence of relapse. Furthermore, [18F] FDG (2-deoxy-2-[18F] fluoro-D- glucose)-positron emission tomography (PET) imaging was performed and the radiomic features from different feature categorizes were extracted to quantify the tumors' phenotype. The animals treated with AuNP+ultrasound exhibited an obvious decline in tumor metabolic parameters such as standard uptake value (SUV), total lesion glycolysis (TLG), and metabolic tumor volume (MTV) compared to other treatment groups.
Conclusion:
These findings strictly propose AuNP as a potent sonosensitizing agent with the potential to use the thermal and mechanical effects of ultrasound so as to cause damage to the focused tumor site, resulting in a strong antitumor efficacy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
233
233
https://ijmp.mums.ac.ir/article_12863_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12863
Absorbed dose to peripheral organs during different methods of dental radiology using radiation estimation models
Zahra
Farzanegan
Medical Physics Student (MSc), Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mansour
Zabihzadeh
Assistant Professor (PhD), Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction:
Dental radiography as one of the most frequent type of radiological examinations is accepted for medical investigations due to their significant benefits nevertheless using ionizing radiation. It has lower radiation dose compared to another radiological examination but because of its high application for children, radiation dose needs attention. Based on affecting many parts of body without any diagnostic information by the radiation and large number of examinations in younger age groups, radiation protection is critical in dental radiography techniques. This study aimed to investigate absorbed dose to peripheral organs during different methods of dental radiology, radiation estimation models and also radiation protection techniques and instruments.
Materials and Methods:
A systematic search of the literature published from 1990 to 2017 in the PubMed, scopus and web of science databases was performed. The following key words combined in different ways: dental radiography, dose and radiation protection.
Results:
CBCT has been discussed as a modality with the greatest radiation dose. Many studies indicated lower patient exposure despite the insignificant impact on the subject image quality, more sensitivity to radiation, which allows lower radiation dose using digital dental radiography. Monte Carlo computations have the ability of dose measurement at any point in the material when the presence of any physical detector is not required. Using high KVP, limited field of view, limitation of radiation field to the necessary anatomy, application of lead foil behind the dental film pockets, filtration, reducing exposure time and correct shield positioning for radiosensitive organs are recommended for radiation protection in dental radiography.
Conclusion:
dental radiography modalities leads to irradiating organs that are adjacent to the examined part that can be decreased using different protection techniques and instruments.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
234
234
https://ijmp.mums.ac.ir/article_12864_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12864
Radiation Oncology Medical Physics Workload calculation: A Change in Current Workload
Mohammad
Mohammadi
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
Fatemeh
Varshoee Tabrizi
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
Sara
Abdollahi
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
Leila
Sobh-Khiz Sabet
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
Fatemeh
Akbari
Department of Medical Physics, Reza Radiotherapy and Oncology Center, Mashhad, Iran
author
text
article
2018
eng
Introduction: It is an essential activity to quantify the Radiation Oncology Medical Physics (ROMP) workload for a safe, secure and progressive department. Due to the most recent development at Reza radiotherapy and Oncology Centre (RROC), a workload calculator tool is provided.
Materials and Methods: The Project was performed in different sections including acquiring information and system abilities and failures, data processing and analysis, recommending the results to the executive section and, receiving and analyzing the feedback from Radiation Oncology Medical Physicists (ROMPs) employed at RROC.
Results: Based on interview with ROMPs, who are engaged with professional tasks at planning, dosimetry, Brachytherapy, health Physics, commissioning a machine or radiotherapy technique, as well as amount of patients referred to RROC for radiotherapy, a workload for ROMPs was estimated. It has been found that for average of 225 new patients per month, 8.55 Full Time Equivalent (FTE) is required. For a commissioning and running advanced techniques, such as Intensity Modulated Radiotherapy (IMRT), the total FTE for ROMP contribution including, planning and Patient Specific Quality Assurance (PSQA) tasks was also found to be 1.74 FTE for every 10 new cases. The FTE for Brachytherapy tasks with average 78.5 cases per month including cylinder, tandem, tandem & ovoid, and esophagus cases, and linear accelerator maintenance the average FTE were found to be 2.49 and 2.34, respectively. The study shows relying the computer based managerial affairs is able to reduce the ROMP administrative tasks significantly.
Conclusion: A professional administrative study for ROMP section will be able to determine the real, secure and safe workload for the section. The workload of ROMPs strongly depends on the level of the treatment quality and it should be taken into account as a dedicated plan for each department.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
235
235
https://ijmp.mums.ac.ir/article_12865_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12865
Rabbit internal dosimetry for iodine-131 using GATE Monte Carlo simulation code: a preclinical trial
Shima
Yavari
Department of Nuclear Medicine, Vali-asr Hospital Tehran University of Medical Sciences, Tehran, Iran
author
Parham
Geramifar
Department of Nuclear Medicine, Shariati Hospital Tehran University of Medical Sciences, Tehran, Iran
author
Maryam
Fallahpoor
Department of Nuclear Medicine, Vali-asr Hospital Tehran University of Medical Sciences, Tehran, Iran
author
Mehrshad
Abbasi
Department of Nuclear Medicine, Vali-asr Hospital Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
One of the main concerns in administration of radiotracers, especially in therapeutic arm, is the amount of delivered dose to the different organs.
Individual variations of anatomy, physiology and underlying pathology in the patients lead to alteration of administered activity.
In the current study we preclinically applied internal dosimetry using an animal model
Materials and Methods:
The SPECT/CT imaging of a rabbit 24 hours after administration of 288μci Iodine-131 was done. Biodistribution of radiotracer was obtained from SPECT, and the CT was used to define attenuation map and the target volume of interest (VOIs).
Dosimetry calculations were performed with GATE Monte Carlo code and S-values for beta and gamma radiation of different organs were calculated.
Results:
The S-values of thyroid as target organ are 1.09×10-4(mGy/MBq/sec) for beta and 1.05×10- 5 for gamma radiation. And S-values of kidneys, lungs, spine, and heart as critical organs are 1.10×10-5, 1.58×10-5, 7.62×10-6, 6.75×10-6 for beta, respectively and 3.9×10-6, 2.69×10-6,
2.63×10-6, 3.27×10-6 for gamma, respectively
Conclusion:
The internal dosimetry is applicable clinically. The response to therapy would be increased and the side effect would be minimized if the prescription using patient specific dosimetry is optimized.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
236
236
https://ijmp.mums.ac.ir/article_12866_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12866
Evaluating the efficacy of various therapeutic modalities in advanced esophageal cancer
Masoumeh
Farsizaban
Department of medicine, zahedan university of medical sciences, zahedan, IR Iran. NO: 09151405378 e-mail address: Ma_farsizaban@yahoo.com
author
Mahsa
Poorjangi
Medical students research commitee , Zahedan University of Medical Sciences , Zahedan, I.R.Iran .NO:09156094283 e-mail address: Mahsapoorjangi@yahoo.com
author
text
article
2018
eng
Introduction:
Esophageal cancer is an invasive and fatal malignancy, with the highest global incidence in southern and eastern Africa and eastern Asia. Patients with advanced localized disease and poor prognosis face a five-year survival rate of 15% to 34%. The research is aimed at evaluating Different strategies have been done to treat esophageal cancer by meta-analysis. Materials and Methods:
This study was a systematic review based on valid medical databases including pubmed and medline and Google Scholar.The search was carried out with the key words of esophageal cancer and survival rate and palliative radiotherapy and chemotherapy and Neoadjuvant chemotherapy. Then all the papers that haveThe criteria for entering the study were reviewed in the last 10 years. Our search for articles in English is limited. Finally, 38 articles were reviewed. The data were analyzed using the meta-analysis method (crash effects model) and software STATA (Ver-11.1).
Results:
Effects of drugs such as Taxane and Irinotecan in combination with platinum and fluoropyrimidines combined with radiotherapy treatment. Which has had a moderate effect. Radiotherapy alone is used to relieve the condition normally for patients with a severe condition. Chemotherapy Together with radiotherapy in general, it has a better effect than radiotherapy alone. Brachytherapy for the insertion in comparison with metal stent to resolve the disorder Swallowing can have a better effect, longer lasting effect on the patient's esophagus. The neoadjuvant 's role in treating it is still unknown.
Conclusion:
2 modalities of radiotherapy and chemotherapy have a therapeutic effect better than eachother alone. To investigate the effect of neoadjuvant chemotherapy and drugs, such as Taxon and Irinotecan, are not enough and there is a need for research in this subject.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
237
237
https://ijmp.mums.ac.ir/article_12867_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12867
Measurement and comparison of head scatter factor for 9MV photon beam using the build-up cap and a columnar mini-phantom
Daryoush
Khoramian
Ramezanzadeh radiation therapy center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Soroush
Sistani
Ramezanzadeh radiation therapy center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
text
article
2018
eng
Introduction: The Sc is an important parameter to monitor unit (MU) calculation in radiation therapy procedure. The aim of this study is to measurement and comparison of head scatter factor (Sc) for 9MV photon beam using the build-up cap and a columnar mini-phantom.
Materials and Methods: The measurements performed using a calibrated ion chamber (Scanditronix / Wellhofer Farmer Type Chamber FC65-G), and electrometer (Scanditronix / Wellhofer, Dose 1 Reference class electrometer). Sc’s values were measured on Neptun linear accelerator. The Sc measured in the source to surface distance (SSD) of 100cm in different square field sizes (5×5 to 38×38 cm) using two available devices: the PMMA build- up cap and dmax dose water equivalent columnar mini-phantom.
Results: Sc’s values for 5×5, 10×10, 15×15, 20×20, 25×25, 30×30, 35×35 and 38×38 cm2 field
sized with columnar mini-phantom were 0.97, 1, 1.02, 1.04, 1.06, 1.07, 1.08, and 1.09, respectively.
Sc’s values for 5×5, 10×10, 15×15, 20×20, 25×25, 30×30, 35×35 and 38×38 cm2 field sized
with build-up cap were 0.96, 1, 1.03, 1.06, 1.08, 1.09, 1.10, and 1.11, respectively. Conclusion: Though measured Sc value using build-up cap in 5×5 cm2 field size was smaller than of those Sc measured using columnar mini-phantom, higher values result in larger field sizes than 10×10 cm2.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
238
238
https://ijmp.mums.ac.ir/article_12868_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12868
Evaluation of Occupational Radiation Dose in One Year for Operators Working in CT Scan Centers
Mohsen
Shoja
Depatment of Radiology, Faculty of Paramedicine, Semnan University of Medical Sciences, Semnan, Iran
author
Shoka
Shahryari
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
author
text
article
2018
eng
Introduction: Becuase of the most radiation dose receiving by human is related to medical radiation exposures, and also Computed Tomography (CT) is a special type of radiography that is one of the main method of radiation exposure today, and it's growing increasingly. Therefore, radio technologists working in CT scan imaging centers, are at risk of radiation. Due to the high amount of radiation factors (like kilo-voltage) in CT scans, we evaluated the annual radiation dose of operators working in CT scan imaging centers in this study.
Materials and Methods: In this study, the radiation dose of 30 operators has been calculated by using tow Thermoluminescence Dosimeter (TLD) for each one. All of operators were working in CT scan imaging centers or hospitas in Tehran. They used TLDs on their medical cover for 3 months. This protocol was repeated 2 times to ensure repeatability. Also the type and number of CT scans that each person has done was recorded.
Results: The recieved dose by TLD was estimated to range from 0.06 to 0.13 mGy (milliGray) in two 3-month periods. Accordingly, the annual dose was estimated to be between 0.12 and
0.26 mGy with mathematical calculations.
Conclusion: The occupational radiation dose for operators working in CT scan centers is as low as background radiation in one year. Also It is much lower than the annual limited dose approved by radiation protection organization. So the result of this study showed a proper protection of radio-technologists in CT scan centers.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
239
239
https://ijmp.mums.ac.ir/article_12869_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12869
Artifact reduction techniques in Cone Beam Computed Tomography (CBCT) imaging modality
Zahra
Farzanegan
Medical Physics Student (MSc), Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mansour
Zabihzadeh
Assistant Professor (PhD), Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction: Cone beam computed tomography (CBCT) was introduced and became more common based on its low cost, fast image procedure rate and low radiation dose compared to CT. This imaging modality improved diagnostic and treatment-planning procedures by providing three-dimensional information with greatly reduced level of radiation dose compared to 2D dental imaging modalities for investigation of maxillofacial skeleton, dentition and the relationship of anatomical structures. However, CBCT is associated with multiple artifacts like. Extinction artifacts, beam hardening artifacts, partial volume effect, aliasing artifacts, ring artifacts and motion artifacts (misalignment artifacts), Noise and scatter. All of them leads to image quality reduction and have capability of Mistakenly considering as a pathological lesion. This study aimed to investigate Cone Beam Computed Tomography artifacts and their reduction procedures.
Materials and Methods: A systematic search of the literature published from 2000 to 2017 in the PubMed, scopus and web of science databases was performed. The following key words combined in different ways: cone beam computed tomography, CBCT Artifacts and artifact reduction.
Results: Artifact is caused by several factors containing reconstruction parameters like small field of views (FOVs), presence of metal objects, patient movement, etc. Artifact reduction methods can have divided into two categorize preprocessing in the projection domain and post processing in the image domain. Limitation of field of view, modification of patient head position or separating dental arches for scatter reduction, Application of high KVP in order to beam hardening reduction, iterative method and projection modification method for metal artifacts are recommended. In addition, Filtration, interpolation, iterative reconstruction and filtering algorithms, application of the smaller voxel size and respiratory gating are other suggested items for artifact reduction in CBCT.
Conclusion: Multiple artifacts accompany CBCT imaging procedures. There for With the aim of improving the quality of the CBCT images; reducing the artifact caused scatter photons , various software-based and hardware-based correction methods are recommended .
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
240
240
https://ijmp.mums.ac.ir/article_12870_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12870
Comparison between artificial neural network and radiobiological modeling for prediction of thyroid gland complications of after radiotherapy
Sevda
Shahbazi
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Aysan
Namdar
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Asghar
Mesbahi
Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
text
article
2018
eng
Introduction:
Hypothyroidism is one of the frequent side effects of radiotherapy of head and neck cancers, breast cancer, and Hodgkin's lymphoma. It is recommended to estimate the normal tissue complication probability of thyroid gland using radiobiological modeling during treatment planning. Moreover, the use of artificial neural network is also proposed as a new method for this aim. The purpose of this study is to compare the results of the radiobiological modeling with the artificial neural network.
Materials and Methods:
Thyroid dose-volume histograms from a dataset of 44 consecutive patients treated with 3D- CRT for head-and-neck cancers and breast cancer were extracted. Dose-volumetric and radiobiological parameters of thyroid gland including the minimum dose, the maximum dose, the mean dose, TD50, EUD, m, n, and NTCP values calculated by LKB model were used as the input variables of the artificial neural network (ANN) method. The results of each method were then compared with each other. Evaluation of the two methods was estimated using the root- mean-square error (RMSE) and the coefficient of determination (R2).
Results:
The values for simulation results were RMSE = 0.008 and R2 = 0.99. Using error estimation criteria, results obtained by the ANN method showed the potential prediction of this method for complications of thyroid gland as same as the radiobiological modeling method.
Conclusion:
Artificial neural network (ANN) can be used in modeling and patients could hopefully benefit from its individualized estimation of normal tissue complications in the clinic.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
241
241
https://ijmp.mums.ac.ir/article_12871_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12871
Kinetics of cell death triggered photothermally using folate-conjugated gold nanoparticles and various laser irradiation conditions in cancer cells
Elham
Zeinizade
Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran;
author
Mousa
Tabei
Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran;
author
Ali
Shakeri-Zadeh
Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran;
author
Habib
Ghaznavi
Cellular and Molecular Research Center, Zahedan University of Medical Sciences (ZaUMS), Zahedan, Iran;
author
Neda
Attaran
Applied Biophotonics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran;
author
Ali
Komeili
Applied Biophotonics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran;
author
Behafarid
Ghalandari
Applied Biophotonics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran;
author
Shayan
Maleki
ENT and Head & Neck Research Center and Department, Iran University of Medical Sciences (IUMS), Tehran, Iran;
author
S.
Kamran Kamrava
Applied Biophotonics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran;
author
text
article
2018
eng
Introduction:
In this study, we explore in detail cell-specific targeting efficacy of nano-photo-thermal therapy (NPTT) method and the resulting responses that are induced by variable laser intensities and exposure times in cancer cells to induce selective apoptosis. We delineate the synthesis of a high-yielding synthetic F-AuNPs by tailoring the surface of gold nanoparticles with folic acid to enhance cell selectivity and specificity.
Materials and Methods:
For this purpose, synthesized F-AuNPs treated cells were irradiated with various laser intensities and exposure duration. Both KB cancer cells, as a folate receptor over-expressing cell line, and L929 normal cells, with low level of folate receptors were used. Following various regimes of NPTT, Cytotoxicity was assessed by MTT assay and comparison of induced apoptosis and necrosis in population of cells were depicted by Annexin/PI staining.
Results:
We report no significant cytotoxicity difference between KB and L929 cell lines at concentrations up to 40 μM of F-AuNPs. Moreover, no significant cell lethality occurred for various laser irradiation conditions. However, in photothermal therapy, the viability of KB and L929 cells was 57% and 83%, respectively. Flow cytometry clearly revealed the kinetics of cell death. The majority of cancer cell death was related to apoptosis (41% apoptosis of 43% overall cell death).
Conclusion:
Together, these findings confirm that F-AuNPs based NPTT can either induces cell death via apoptosis or necrosis. The main factor determining whether a cell will die due to apoptosis or necrosis on-demand with PTT depends on laser heating level. Our main target must be to only trigger apoptosis during PTT by using suitable irradiation conditions. As a result, folate targeting ability of the F-AuNPs and laser energy threshold to induce selective apoptosis in cancer cells were shown.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
242
242
https://ijmp.mums.ac.ir/article_12872_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12872
Tumour radiobiology beyond fractionation
Hossein
Mozdarani
Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
text
article
2018
eng
Historically it has been shown repeatedly that single high doses of radiation do not allow a therapeutic differential between tumor and critical normal tissues but dose fractionation does. The purpose of conventional dose fractionation is to increase dose to the tumor while preserving normal tissue function. Tumors are generally irradiated with 2Gy dose per fraction delivered daily to a more or less homogeneous field over a 6-week time period to a specified total dose. In this treatment protocol, biological effect is based on a linear term and a quadratic term based on Lea and Catchside 1942; Radiation-induced chromosome
aberrations as proposed by Kellerer and Rossi 1972 and theory of dual radiation action
based on microdosimetry. Over 90% of radiation oncologists use the linear quadratic model.
There are radiobiological mechanisms that impact the response to a fractionated course of
radiation therapy. The classical 4R mechanisms act on every solid tumor following
irradiation. Repair of sublethal damage spares late responding normal tissue preferentially.
Redistribution of cells in the cell cycle increases acute and tumor damage but has no effect
on late responding normal tissue. Repopulation spares acute responding normal tissue, no
effect on late effects and Reoxygenation that increases tumor damage without any effect in
normal tissues. However, Radiobiological parameters derived from clinical altered
fractionation protocols such as hyperfractionation, accelerated fractionation and
hypofractionation schedules may not follow these mechanisms. Moreover, other biological
processes such as intrinsic radiosensitivity, radioadaptation and bystander effect, might
alter radiation effects on tumor and normal tissue leading to an altered therapeutic gain
factor. Some affected patients with various types of cancers show higher intrinsic
radiosensitivity. Among these is breast cancer patients who show distinct radiosensitivity
compared to normal individuals. This effect which is manifested as higher chromosomal
aberrations and DNA repair impairment is now known as a good biomarker for breast cancer
screening and prediction of prognosis. The other major concern in fractionation is the
phenomenon of radioadaptation or radiation hormesis following first time irradiation of
cells. Furthermore, radiation-induced bystander effect leads to perturbations to tissue social
control and induction of genomic instability and delayed or immediate mutations in areas
not receiving a direct deposition of energy. All these biological phenomena acting in low dose
radiation response of tumor and normal tissues may lead to altered therapeutic gain in
fractionation regimens will be discussed.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
243
243
https://ijmp.mums.ac.ir/article_12873_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12873
Modulating effects of melatonin, vitamin C and saffron alone or in combination on radiation induced cell lethality; an in vitro study with Hela cells
Hossein
Mozdarani
Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Sara
Ghorbanian
Department of Genetics, University of Sistan and Baluchestan, Zahedan, Iran.
author
Sohail
Mozdarani
Cytogenome Medical Genetic laboratory, Ale-Ahmad Highway, Parvaneh Street, Chamran Medical Building, Tehran, Iran.
author
Hassan
Nosrati
Cancer Research Center, Cancer Institute of Iran, Tehran, Iran.
author
Sahar
Mozdarani
Cytogenome Medical Genetic laboratory, Ale-Ahmad Highway, Parvaneh Street, Chamran Medical Building, Tehran, Iran.
author
text
article
2018
eng
Introduction:
Radiation countermeasures are defined as use of an agent to minimize the deleterious effects of radiation therapy by administering the compound after the radiation exposure has occurred, regardless of toxicity. In spite of extensive study in this field, yet there is no suitable radioprotector introduced. In this study two naturally occurring antioxidants were studied on radiation induced cell lethality.
Materials and Methods:
Various doses of melatonin, saffron and vitamin C were examined for their antioxidant capacity by using DPPH test. Hela cells were treated with optimum doses of melatonin, saffron and vitamin C; 2 hours prior to gamma irradiation alone or in combination. Treated cells were irradiated with various doses of gamma rays (2, 4, 8 Gy), then cells were plated in 96 well plates for MTT assay. Cells were fixed at 48 and 72 hours after plating and reading was done ELISA reader.
Results:
Results showed cell viability reduced slightly after 48 h irradiation. Pretreatment of cells with melatonin and vitamin C increased cell lethality considerably for dopses of 2 and 4 Gy, but surprisingly presence of melatonine and vitamin C led to an increase in cell viability when combined with 8 Gy gamma rays. Combination of these agents with saffron showed similar effects. Similar results were observed for 72 h sampling time. However, protective effect of these agents was more pronounced when using 8 Gy radiation dose.
Conclusion:
Results indicate that despite the antioxidant potential of melatonin, saffron and vitamin C, when combined with low and moderate doses of gamma rays (2 and 4 Gy) led to increased cytotoxic effects of ionizing radiation. However, at high dose of gamma rays (8 Gy) radioprotective effect was seen. The dual action of these agents with low and high doses of ionizing radiation is not known.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
244
244
https://ijmp.mums.ac.ir/article_12874_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12874
Machine learning based Visual Evoked Potential (VEP) Signals Recognition
Sara
Hashemi
Ph.D. Student, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran.
author
and Mohammad Saber
Hashemi
M.Sc. Student, School of Mechanical Engineering, College 2 of Engineering Schools, University of Tehran. Tehran, Iran.
author
text
article
2018
eng
Introduction:
Visual evoked potentials contain certain diagnostic information which have proved to be of importance in the visual systems functional integrity. Due to substantial decrease of amplitude in extra macular stimulation in commonly used pattern VEPs, differentiating normal and abnormal signals can prove to be quite an obstacle. Due to developments of use of machine learning techniques in interdisciplinary fields, deployment of machine learning in the brain electrical activity fields results in use of less expensive databases and prevention of duplication and forgery of activities.
Materials and Methods:
In this study 54 normal Visual evoked potentials and 16 abnormal VEPs have been used. Signals have been classified via two main supervised learning methods, neural network and support vector machine.
Results:
The results of these supervised learning techniques have been compared with similar models post feature extraction carried out by Daubechies wavelet feature extraction. Results indicate best error rate of %1.45 in SVM and %7.25 in neural network prior to feature selection via wavelet. After applying wavelet transform, SVM accuracy increased to %100 accuracy and %94.22.
Conclusion:
The choice of a suitable feature selection method besides SVM and neural network can prove to be highly compatible in the field of brain electrical activity fields.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
246
246
https://ijmp.mums.ac.ir/article_12876_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12876
Comparison of dosimetric radiotherapy of whole left- breast cancer using conventional tangential wedge-based techniques (CTT) and three intensity modulation techniques (IMRT)
Amir
Jafari
Medical Physics Department, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Ahmad
Shanei
Medical Physics Department, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Iraj
Abedi
Medical Physics Department, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Alireza
Amoheidari
Radiation Oncology Department, Isfahan Milad General Hospital, Isfahan, Iran.
author
text
article
2018
eng
Introduction:
Whole breast radiotherapy after breast-conserving surgery decrease the risk of local recurrence. this study investigates the dosimetric aspects of intensity modulated radiotherapy (IMRT) compared to conventional tangential wedge-based beams techniques (CTT) of the whole breast in early stages breast cancer patients.
Materials and Methods:
Computed tomography images of 35 patients with left sided breast cancer used for whole breast radiotherapy planning were examined. They were planned using four different radiotherapy technique, 1) conventional tangential wedge-based beams techniques (CTT);
2) six beams intensity modulated radiotherapy (IMRT-6F); 3) seven beams intensity modulated radiotherapy (IMRT-7F); and 4) nine beams intensity modulated radiotherapy (IMRT-9F). The PTV dose prescribed was 50 Gy in 25 fractions and V47.5 ≥ 95%. Dose distribution of PTV and OARs, the homogeneity index (HI), and conformity index (CI) were measured and compared to each other.
Results:
All of the IMRT plans improved CI (CTT: 0.93 ± 0.019; IMRT-6F: 0.95 ± 0.016; IMRT-7F: 0.96 ± 0.014;
IMRT-9F: 0.97 ± 0.010), HI (CTT: 0.21 ± 0.021; IMRT-6F: 0.17 ± 0.013; IMRT-7F: 0.16 ± 0.014; IMRT-9F: 0.15 ± 0.018), mean dose PTV (CTT: 50.88 ± 0.48Gy; IMRT-6F: 51.93 ± 0.37Gy; IMRT-7F: 51.99 ± 0.38Gy;
IMRT-9F: 52.14 ± 0.33Gy) and significantly increase volume of ipsilateral lung receiving more than 5Gy and 20Gy (V5Gy - V20Gy) (CTT: 20.05 – 12.69; IMRT-6F:41.69 -16.59; IMRT-7F: 42.13 – 16.74; IMRT-
9F: 48.284 - 17.26) too increase mean dose of Heart (CTT: 6.61 ± 1.47Gy; IMRT-6F: 6.33 ± 1.55Gy; IMRT- 7F: 7.35 ± 2.83Gy; IMRT-9F: 8.35 ± 3.64Gy) compared to CTT. Mean dose of contralateral Breast and contralateral Lung too increase than CTT.
Conclusion:
From the dosimetric point of view, the IMRT plans were not significantly advantageous over the 3DCRT plans. IMRT produces better the homogeneity and conformity index of the PTV, but increase low doses to OARs.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
247
247
https://ijmp.mums.ac.ir/article_12883_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12883
Estimation of spinal loads using a detailed finite element model of the L4-L5 lumbar segment derived by medical imaging kinematics; a feasibility study
Mohammad Saber
Hashemi
M.Sc. Student, School of Mechanical Engineering, College 2 of Engineering Schools, University of Tehran. Tehran, Iran.
author
Navid
Arjmand
Ph.D., School of Mechanical Engineering, Sharif University of Technology, Tehran, Iran.
author
text
article
2018
eng
Introduction:
Low back pain is the most prevalent orthopedic disorder and the first main cause of poor working functionality in developed as wells as many developing countries. In Absence of noninvasive in vivo measurement approaches, biomechanical models are used to estimate mechanical loads on human joints during physical activities. To estimate joint loads via musculoskeletal models, the calculation of muscle forces is of importance. It is however difficult to estimate muscle forces as the number of muscles, i.e. unknown parameters, is far more than the existing degrees of freedom; the system is highly redundant.
Materials and Methods:
In this study, instead of muscle forces estimation, their effects (i.e., rotations and displacements) is measured by medical imaging techniques and prescribed to a detailed finite element model of the L4-L5 spine segment to determine intervertebral disc pressure as a representative of compressive forces acting on the joint. A previously validated geometrically-detailed passive finite element model of the L4-L5 segment was used. Disc, facet joints, vertebrae, and ligaments were simulated with appropriate elements/material properties. Rotations and displacements of the L4 and L5 vertebrae from supine to upright and from upright to trunk flexion of 10 degrees were measured via x-ray imaging.
Results:
The kinematics were prescribed to the L4 and L5 centroids. Maximal intradiscal pressure of
~0.45 MPa was predicted for the simulated tasks that was in agreement with in vivo data in the literature.
Conclusion:
Preliminary results indicate feasibility of this kinematics-based approach to predict in vivo spine loads.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
248
248
https://ijmp.mums.ac.ir/article_12884_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12884
Investigation of the dose enhancement effect due to gold nanoparticles at 18 MV radiotherapy using MAGIC-f and Monte Carlo methods Thoraco-Lumbar spinal cord fMRI in 3T Magnetic field
Hossein
khosravi
Department of Radiology, Faculty of Paramedical, Hamadan University of Medical Sciences, Hamadan, Iran.
author
Bijan
Hashemi
Department of Medical Physics, Tarbiat Modares University, Tehran, Iran.
author
Seyed Rabi
Mahdavi
Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction:
Normoxic MAGIC-f polymer gels are established dosimeters used for three dimensional dos uantifications in radiotherapy. The high atomic number nanoparticles such as gold are nov adiosensitizers used to enhance doses delivered to tumors. The aim of this study was t vestigate the effect of gold nanoparticles (GNPs) in enhancing percentage depth doses (PDD ithin the MAGIC-f gel exposed to linac high energy photon beams (18MV).
Materials and methods:
The MAGIC-f gel was fabricated based on its standard composition with some modifications an oured into falcon tubes. The PDDs in the tubes containing the gel were calculated using a commo onte Carlo code (MCNPX) followed by experimental verifications. Then, the GNPs with a verage diameter of 15 nm and a concentration of 0.1 mM were embedded in the gel, poured int milar falcon tubes and irradiated to 18 MV beams of a Varian 2100 linac. Finally, simila xperimental and Monte Carlo (MC) calculations were conducted to determine the effect of usin e GNPs on some dosimetric parameters of interest.
Results:
The results of experimental measurements and simulated MC calculations showed a dos nhancement factor (DEF) of 1.12±0.07 and 1.13±0.06 respectively due to the use of the GNP hen exposed to 18 MV linac energies.
Conclusion:
The results indicated that the fabricated MAGIC-f gel could be recommended as a suitable tool fo ree dimensional dosimetric investigations at high energy radiotherapy procedures wherein th NPs are used.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
249
249
https://ijmp.mums.ac.ir/article_12885_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12885
Graphene Quantum Dots-Coated Bismuth Nanoparticles for X-ray CT Imaging-Guided Photothermal therapy of Cancer Cells
Samireh
Badrigilan
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Department of medical physics, Faculty of Medical, Tabriz University of Medical Sciences, Tabriz, Iran
author
Behrouz
Shaabani
Department of Inorganic Chemistry, Faculty of Chemistry, Tabriz University, Tabriz, Iran
author
Nahideh
Ghareh aghaji
Department of Radiology, Faculty of Paramedical, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Asghar
Mesbahi
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Department of medical physics, Faculty of Medical, Tabriz University of Medical Sciences, Tabriz, Iran
author
text
article
2018
eng
Introduction: Theranostic nanoparticles, which integrate both diagnostic and therapeutic capabilities into one nanoagent, has great promise to ablate more effective tumoral tissue by optimizing and real-time monitoring treatment interventions, as well as monitoring therapeutic response to corresponding effect. Multifunctional theranostic nanoagent based on graphene quantum dots (GQDs)-coated Bi nanohybrids (GQDs-Bi NPs) was developed and investigate their multimodal imaging and PTT performance.
Materials and Methods: The GQDs-Bi NPs were fabricated by utilizing simple two-step synthesis: GQDs as shell and Bi NPs as core in presence of GQDs. By hemolysis and MTT test, blood compatibility and cellular toxicity of GQDs-Bi NPs were examined. For phantom CT imaging, the GQDs-Bi NPs aqueous solutions at various concentrations of Bi element scanned by a clinical CT scanner (GE HiSpeed) (160 mA, 80,120 and140 kV). The corresponding CT values (HU) were measured by imageJ software. To evaluate the photothermal effect, the GQDs-Bi NPs dispersions at different concentrations of active Bi metal were irradiated with an 808 nm-NIR-laser (1.7 W·cm-2) for 10 min and a thermocouple probe was used to record the temperature of suspensions.
Results: The GQDs-Bi NPs showed satisfactory cytotoxicity and hemolysis behavior. The heavy metal Bi component (Z=83) in the GQDs-Bi NPs produced much higher Hounsfield units (173 HU) than the contrast agents based on small molecules iodine (134 HU), corresponding, 1 mg Bi/ml provided an equivalent X-ray attenuation as dotarem contain of
1.5 mg/mL Iodine. A strong and steady absorbance was found for GQDs-Bi NPs in the whole NIR range, as well as high photo-to-thermal conversion capability and photostability, encouraging a high antitumor PTT efficiency. The GQDs-Bi NPs could successfully kill in vitro MCF-7 and HeLa cancer cells under NIR irradiation with killing effect dependent on dose compared to those received laser only (3.0%).
Conclusion: GQDs-Bi nanotheranostic may become an effective tool for CT imaging-guided therapy for personalized cancer treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
250
250
https://ijmp.mums.ac.ir/article_12886_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12886
Effects of low electromagnetic waves on thymus size, testis and body weight and therapeutic role of vitamin C in mice
Setareh
Davachi
MSc, Department of Biochemistry and Biophysics, Mashhad Branch, Islamic Azad University, Iran.
author
Ghorban
Safaeian layen
Assistant Professor, Department of Radiology Technology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
author
Ali
Neamati
Associate Professor, Department of Biochemistry and Biophysics, Mashhad Branch, Islamic Azad University, Iran.
author
Mina
Nouri
MSc medical physics, Department of Radiology Technology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
Introduction: Results of several studies on different effects of electromagnetic waves reveal that change of field intensity, even milli tesla has various biological effects, therefore investigation on electromagnetic effects can be done in very wide range. In this research, amount of these effects on biomass, thymus, testis and therapeutic role of vitamin C in improvement of changes caused by electromagnetic field, have been studied.
Materials and Methods: In this experimental study, 24 adult male mice (Balb/C) were divided into 3 groups. The control group consist of 8 mice were kept in normal conditions. The group exposure to Electromagnetic field consist of 8 mice, which were exposed to ELF (50Hz, 4Mt) for 15 days (4 hours per day), and the group that exposure to Electromagnetic field supplemented with vitamin C, contains 8 mice that were exposed to ELF (50Hz, 4Mt) for 15 days (4 hours per day) and 0.5 cc vitamin C were injected intraperitoneally 7 times. This injection was done 3 times a week. After 15 days, mice were anesthetized by chloroform, following careful dissection, organs were splitted over then this samples were dissected and measured. Data was analyzed using one way ANOVA test.
Results: The results show electromagnetic waves lead a significant reduction in body weight and receive appropriate dose of vitamin C may have therapeutic role which reduce damages caused by 50 Hz/4 mT on Balb/C male adult mice.
Conclusion: According to this research exposure to electromagnetic waves reduces thymus and testis weight significantly which may root in reduced cell division and inhibition of apoptosis, so simultaneous deliver if vitamin C didn’t show significant effect on thymus and testis.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
251
251
https://ijmp.mums.ac.ir/article_12887_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12887
Design and Fabrication of a Four-Dimensional Respiratory Phantom for Studying Tumor Movement in Radiotherapy with Magnetic Resonance Imaging
Zahra
Akmali
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
Student Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Daryoush
Shahbazi-Gahrouei
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Mohammad Amin
Mosleh-Shirazi
Medical Imaging Research Center & Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Milad
Baradaran-Ghahfarokhi
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Nader
Fallahian
Department of Orthotics and Prosthetics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
author
Sadegh
Sherkat
Department of Mechanical Construction, Islamic Azad University, Najafabad Branch, Isfahan, Iran
author
text
article
2018
eng
Introduction: In radiation therapy, determining the location of the tumor accurately during irradiation is one of the most important requirements. However, lung tumors are not fixed in a single location and move during irradiation due to respiratory motion. Due to limitations in assessing such movements, using a lung phantom can be useful and operational for their fast, easy and inexpensive assessment. Moreover, Magnetic Resonance Imaging (MRI)- guided radiation therapy is an emerging modality and research is needed increasingly in this field. An advanced aspect of MRI-guidance is its use in respiratory-correlated radiation therapy. To facilitate research on this topic, the aim of this study was to design and build a four-dimensional (4D) respiratory phantom for studying tumor movements in lung radiation therapy.
Materials and Methods: By molding a normal human lung, an artificial lung made of silicon was constructed. The chest was made of plexiglas and a double-walled container. The wall was filled with water to increase the MR signal strength. A 1.5-liter thin bag of silicon was made as a synthetic diaphragm and was placed into the chest. Seven tumors were embedded in different parts of the lung. A piston pump was used to simulate the breathing and an engine and gearbox were used to create the reciprocating motion.
Results: The phantom is MRI compatible, unlike many of the previously designed 4D lung phantoms. Inspecting the MRI, CT and fluoroscopy x-ray scans taken of the phantom, useful information could be derived from the images which could be applied to simulating and examining the motion and the types of movement of lung tumors.
Conclusion: The constructed lung phantom can be a useful tool for research into respiratory- correlated radiation therapy and its new techniques, as well as quality assurance of a variety of 4D imaging devices and protocols.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
252
252
https://ijmp.mums.ac.ir/article_12888_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12888
The Role of radiobiological parameters on Tumor control probability (TCP) in prostate cancer
Asghar
Mesbahi
Department of medical physics, Tabriz University of Medical Sciences, Tabriz, Iran
author
Amir
Khorasani
Department of medical physics, Isfahan University of Medical Sciences, Isfahan, Iran
author
Farshid
Mahmoudi
Department of medical physics, Isfahan University of Medical Sciences, Isfahan, Iran
author
Fahimeh
Aminolroayaei
Department of medical physics, Kashan University of Medical Sciences, Kashan, Iran
author
Naser
Rasouli
Department of medical physics, Isfahan University of Medical Sciences, Isfahan, Iran
author
text
article
2018
eng
Introduction: The aim of this study was to evaluation radiobiological modeling parameters on tumor control probability (TCP) for prostate cancer in three different models. These parameters included α⁄β ratios and cell surviving fraction at 2 Gy (SF2).
Materials and Methods: The Poisson, equivalent uniform dose (EUD) and linear quadratic (LQ) models was used as the radiobiological models. TCP was calculated in 10 prostate cancer patients as a function of α⁄β ratios (1.5-20) for all radiobiological models and SF2
(0.3-0.7) for LQ model. For each patient, 3D-CRT and IMRT plans were designed to deliver, on average 76 Gy and 82 Gy to planning target volume, respectively.
Results: The TCPs calculated by Poisson model were dependent on α/β, results demonstrated that dose escalation from 76 Gy in 3D-CRT to 82 Gy for IMRT caused 5% improvement in TCP for prostate cancer considering the α/β of 10 and higher TCP for IMRT relative to 3D-CRT was seen for α/β higher than 5. According to our results for EUD model the TCPs were independent on α/β. In the LQ model with increase in α/β in specific SF2, TCP will not change remarkable. but with the change of SF2 from 0.7 to 0.3, TCP values change from 0 to 100 % at the prescribed doses in both treatment planning’s.
Conclusion: Different mathematical models provided different quantitative outcome for TCP of prostate cancer plans. The IMRT plans were significantly advantageous over the 3DCRT plans with some small variations in each patient. more studies are needed for the optimization of radiobiological models for the prediction of the treatment outcomes in radiation therapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
253
253
https://ijmp.mums.ac.ir/article_12889_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12889
Effects of Arbutin on Radiation-Induced Micronuclei in Mice Bone Marrow Cells and Its Definite Dose Reduction Factor
Saba
Nadi
Department of Radiobiology and Radiation Protection, Babol University of Medical Sciences, Babol, Iran
author
Ali
Shabestani Monfared
Cellular & Molecular Biology Research Center, Department of Medical physics, Babol University of Medical Sciences, Babol, Iran
author
Hossein
Mozdarani
Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Aziz
Mahmodzade
Laboratory of Cytogenetic, Novin Medical Radiation Institute, Tehran, Iran
author
Mahdi
Pouramir
Department of Biochemistry, Cellular and Molecular Biology Research Center, Babol University of Medical Sciences, Babol, Iran
author
text
article
2018
eng
Introduction:
Interactions of free radicals from ionizing radiation with DNA can induce DNA damage and lead to mutagenesis and carsinogenesis. With respect to radiation damage to human, it is important to protect humans from side effects induced by ionizing radiation. In the present study,the effects of arbutin were investigated by using the micronucleus test for anti- clastogenic activity, to calculate the ratio of polychromatic erythrocyte to polychromatic erythrocyte plus normochromatic erythrocyte (PCE/PCE+NCE) in order to show cell proliferation activity.
Materials and Methods:
Arbutin (50, 100, and 200 mg/kg) was intraperitoneally (ip)administered to NMRI mice two hours before gamma radiation at 2 and 4 gray (Gy). The frequency of micronuclei in 1000 PCEs (MnPCEs) and the ratio of PCE/PCE+NCE were calculated for each sample. Data were statistically evaluated using one-way ANOVA,Tukey HSD test, and t-test.
Results:
The findings indicated that gamma radiation at 2 and 4 Gy extremely increased the frequencies of MnPCE (P<0.001) while reducing PCE/PCE+NCE (P<0.001) compared to the control group. All three doses of arbutin before irradiation significantly reduced the frequencies of MnPCEs and increased the ratio of PCE/PCE+NCE in mice bone marrow compared to the non-drug-treated irradiated control (P<0.001). All three doses of arbutin had no toxicity effect on bone marrow cells. The calculated dose reduction factor (DRF) showed DRF=1.93 for 2Gy and DRF=2.22 for 4 Gy.
Conclusion:
Our results demonstrated that arbutin gives significant protection to rat bone against the clastogenic and cytotoxic effects of gamma irradiation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
254
254
https://ijmp.mums.ac.ir/article_12890_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12890
Evaluation of the effect of dental filling material on IMRT treatment planning in patient with nasopharyngeal cancer
Pegah
saadatmand
Medical Physics Department, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Ahmad
Shanei
Medical Physics Department, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Iraj
Abedi
Medical Physics Department, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Alireza
Amoheidari
Radiation Oncology Department, Isfahan Milad General Hospital, Isfahan, Iran.
author
text
article
2018
eng
Introduction:
Presence of dental filling material (DFM) such as amalgam in treatment patient with nasopharyngeal cancer (NPC) is common. Streaking artifact Arising from this high density material in computed tomography (scan), may lead to perturbation in dose calculation and dose delivery. Widespread performance of intensity-modulated radiotherapy (IMRT) for NPC using anterior beams that pass through the part severely affected by artefacts prior to reaching the target volume, raise concern about the effect of dental amalgam. This study quantifies the effect of dental amalgam on dose distribution target volume and organ at risk, normal tissue complication probability (NTCP) and tumor control probability (TCP).
Materials and Methods:
IMRT optimization two groups of 15 early-stage NPC patients with or without dental amalgam by prescribe 70 Gy to planning target volume performed by using the prowess panther treatment planning system. We used one plan nine field arrangement (F9E) and three plan of seven field (F7, F7E, F7P) arrangement with different angle. The dose volume histograms (DVHs), monitor units (MUs), Homogeneity index (HI), conformity index (CI) and TCP of PTVs, NTCP spinal cord, brain stem and parotid gland were analyzed.
Results:
Mean dose PTV in F7, FVE, F7P and F9E plan were 71.25±1.55, 72.06±0.96, 71.65 ±1.28 and 71.82±0.53 respectively in patients with DFM and 71.52±1.02, 71.51 ± 0.61, 71.30 ±
0.61 and 71.95 ± 0.80 in patient without DFM, Showing slight increase in mean dose of target volume. V95 of PTV shows insignificant different in two group. Mean TCP in F7, FVE, F7P and F9E plan were 95.06±0.45%, 95.18±0.54%, 94.93 ±0.68% and 95.05±0.42% in patient with DFM and 94.86±0.62%, 94.74 ± 0.43%, 94.80 ± 0.58% and 95.50 ± 0.40% in patient without DFM that shows insignificant different in two group. Mean HI of PTV-70 in four plans in presence of DFM shows a slight decrease compared than the other. Mean and maximum dose Spinal cord, brain stem and parotid and their NTCP in presence of DFM show a slight decrease.
Conclusion:
According to the results, dental amalgam led to slight increase in TCP, mean dose target volume and slight decrease in mean dose some OARs and their NTCP. Average dose target volume and some organ at risk that consider for this study demonstrates no meaningful
difference exist in DVH and biological parameter in two group of patient.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
255
255
https://ijmp.mums.ac.ir/article_12891_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12891
Application of Magnetic Resonance Imaging (MRI) as a safe & Application of Magnetic Resonance Imaging (MRI) as a safe & non-destructive method for monitoring of fruit & vegetable in postharvest period
Hamideh
Fatemi
PhD student of Olericulture, Mohaghegh ardabili University, Ardabil, Iran
author
Ghorban
Safaeian layen
Department of Technology of Radiology, school of paramedical science, Mashhad University of Medical Science, Mashhad, Iran
author
Majid
Azizi
Full Professor, Department of Gardening Faculty of Agriculture, Ferdowsi University of Mashhad, Iran
author
Ali
Feyzi laein
Diagnostic Radiologic Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
To investigate and control quality, one must be able to measure quality-related attributes. Quality of produce encompasses sensory attributes, nutritive values, chemical constituents, mechanical properties, functional properties and defects.
MRI has great potential for evaluating the quality of fruits and vegetables. The equipment now available is not feasible for routine quality testing. The image and resolution produced by MRI is quite detailed and can detect tiny changes of structures within the body. For some procedures, contrast agents, such as gadolinium, are used to increase the accuracy of the images. MRI additionally quality, can even examine the histology, histochemistry and structural characteristics of samples. He also mentioned that MRI is used as an on-line sensor in postharvest sorting and processing situations. The equipment now available is not feasible for routine quality testing; however, costs and capabilities are rapidly improving. Each sensor method is based on the measurement of a given constituent or property; therefore, its ability to measure overall quality is only as good as the relationship of that constituent or property to quality as defined for a particular purpose. Improved statistical methods for combining the inputs from several measurements into classification algorithms
are being developed
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
256
256
https://ijmp.mums.ac.ir/article_12892_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12892
New electrical device for field coincidence quality control test in linear accelerators
M.H.
Bahreyni Toosi
Medical Physics Research Center, Medical Physics Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Ghorban
Safaeian layen
Department of Technology of Radiology, school of paramedical science, Mashhad University of Medical Science, Mashhad, Iran
author
Ali
Feyzi
Department of Technology of Radiology, school of paramedical science, Mashhad University of Medical Science, Mashhad, Iran
author
Mahdi
Heravian Shandiz
Department of Technology of Radiology, school of paramedical science, Mashhad University of Medical Science, Mashhad, Iran
author
Amir Hossein
Ziaei
Department of Technology of Radiology, school of paramedical science, Mashhad University of Medical Science, Mashhad, Iran
author
Zahra
emamverdian
Department of Biomedical Engineering, Islamic Azad University of Mashhad Branch, Mashhad, Iran
author
text
article
2018
eng
Testing of the coincidence of a linear accelerators X-ray field and the light field as a quality control test is often done in a subjective method, involving the manual marking of pieces of film and the visual inspection of the film after irradiation. The purpose of this study was to develop an objective method for performing this test, while also increasing the accuracy, precision and the speed of the test. The new method uses a portable, lightweight an inexpensive device containing optically-shielded and nonoptically-shielded photo diodes to detect the location and dimensions of the light and x-ray fields. The measurement results are analyzed and drawn using purpose-written user friendly software. This system is able to reliably measure the coincidence of the two fields with 0.5 mm accuracy and a standard deviation of 0.02 mm, which is well within the tolerance recommended by AAPM Task Group 42. This proposed method allows accurate and precise measurements to be obtained, through a largely automated process, resulting in measurements that have substantially reduced sensitivity to subjectivity
or human error, compared with the standard film-based technique.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
257
257
https://ijmp.mums.ac.ir/article_12893_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12893
Evaluation of glandular dose in mammography in the presence of breast cyst using Monte Carlo simulation
Zeinab
Kave
Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences,
author
Mohamad reza
Deevband
Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences,
author
Mahdi
Ghorbanee
Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences,
author
text
article
2018
eng
Introduction:
Average glandular dose (AGD), entrance skin air kerma (ESAK) and normalized glandular dose (DgN) are the main dosimetric quantities in mammography. In this study, DgN is evaluated in the presence of breast cyst, which is a common disease among women and the influence of size, number and location of the cysts on the DgN is investigated.
Materials and Methods:
Payamed mammography unit was simulated by MCNPX Monte Carlo code and the validation of the simulation was performed by comparing the photon spectrum and percentage depth dose from the simulations by the other studies and measurement. DgN was assessed in the presence of breast cysts. This was performed by simulation of a homogeneous breast phantom which contained spherical cysts. These cysts were in different sizes, numbers and positions. DgN values were compared for the cystic phantom by those related to a normal homogenous phantom without cyst.
Results:
The results of the simulation in this study are in agreement with the other studies and the validation of the simulation results is confirmed. In the cystic phantom the DgN values have differences ranging from -7% to +14% compared with the normal breast phantom. The results show that the DgN in presence of cysts in the breast phantom depends on the size, number and positon of cysts, but it is independent of breast thickness, glandular fraction and tube voltage.
Conclusion:
Even though the breast cyst is a high prevalent disease in women over 35 years, this effect has a little impact on dose calculation in mammography. Howevere, in the case of large sizes and various number of cysts the influence of presence of cysts in the breast is considerable. It is recommended that, if it is possible, the effect of the presence of breast cysts on normalized glandular dose calculation be taken into account in dosimetry in mammography.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
258
258
https://ijmp.mums.ac.ir/article_12894_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12894
Statistical Analysis of Instantaneous Effect of Polarized He-Ne Laser Radiation on the Elastic Modulus of Soft Biological Tissue
Farideh
Motaghian
Atomic physics Faculty of Department of Physics, Sharif University of Technology, Tehran, Iran
author
Ahmad
Amjadi
Atomic physics Faculty of Department of Physics, Sharif University of Technology, Tehran, Iran
author
text
article
2018
eng
Introduction: This work is dedicated to investigating the effect of applying polarized He-Ne laser beam (λ= 632 nm, 10 mW, 1 j/cm2) with polarization direction perpendicular to the stress direction on the tensile strength of biological tissue (elasticity index of the Pleura 10*4*0.1 mm).
Method and Material: The optimized characteristics of the laser illumination in the minimum times of radiation is detected here through some series of designed experiments and the results are completely applicable to the new investigations. To achieve the purpose, the experiments are designed in full factorial design model to study the effecting factor of viscoelastic modules of the pleura. The employed factor is time duration of the exposure. different irradiation timing is 5 s, 10 s, 15 s and 20 s.
Result: Through the variance analysis it is found that time duration of radiation plays very important role on its viscoelastic characteristics. Additionally, it is revealed that a special condition, the time of exposure =10 sec, leads to the highest value of relative elastic modulus, i.e., the most increase in the tensile strength of the Pleura because of dehydration of cells is happened in longer time irradiation than 10s and no effect in less duration than 10s.
Conclusion: This conclusion can be useful in dealing with wound scars, reforming the shape of the cornea, cartilage reshaping and et.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
259
259
https://ijmp.mums.ac.ir/article_12895_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12895
Proton Therapy of eye using MCNPX code
S.
Safaiean
Islamic Azad University, Tehran Center Branch
author
M.
Salehi Barough
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
S.P.
Shirmardi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
text
article
2018
eng
Introduction: Proton radiotherapy is the one of advanced teletherapy methods. The protons deposit their maximum energy in a position called Bragg peak. Therefore, for treatment of cancer, the tumor should be placed at the Bragg peak or SOBP. The scattered photons and neutrons is a challenge in proton radiotherapy. The aim of this study is calculation of absorbed dose from scattered photon and neutron in eye proton therapy.
Materials and Methods: In this study, the simulations were done using MCNPX simulation code. For this, a spherical tumor with 0.6 cm diameter was considered in the eye phantom. The eye phantom has been irradiated with proton beam of 50MeV. Tally F6 was used for dosimetry of scattered neutron and photons.
Results: The results show that the absorbed dose per proton due to scattered neutron and photons in eye tissue are 8.817e-14 Gy and 1.653e-13 Gy respectively.
Conclusion: In proton therapy of eye, the tumor can be treated accurately and the minimum absorbed dose and damage reaches the surrounding tissues. The results show that less than 1% of the total dose of protons is absorbed in the adjacent tissues.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
260
260
https://ijmp.mums.ac.ir/article_12896_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12896
Compare the organs at risk in breast-conserving three- dimensional conformal radiotherapy (3D-CRT) based on patient\\\'s breast size
Yazdani
Sohaila
MSc of Medical Physics, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Yarahmdi
Mehran
Assistant Professor, Department of Medical physics, Kurdistan University of Medical Sciences, Sanandaj, Iran, (Corresponding Author), Tel:+98-87-33611045, yarahmadi.mp@gmail.com
author
text
article
2018
eng
Introduction:
Breast cancer is the most common cancer among women. Radiotherapy plays an important role in the treatment of breast cancer and essential part of the standard treatment after breast-conserving surgery, routinely done to eliminate the microscopic residual cancer. The heart and lungs are one of the most important organs at risk of breast cancer radiotherapy that their exposure are unavoidable. Pneumonia and Pericardia are the most common complications of lung and heart radiation exposure, respectively.
Materials and Methods:
In this study, 20 patients undergoing radiotherapy after breast-conserving surgery were studied. The mean age of patients was 45 years old in the range of 30-60 years. Patients were treated by 3D-CRT with a single-isocenter tri-field technique including two apposite tangent fields and a supraclave field. To optimize the dose distribution, the wedge with suitable angle was placed in front of the beam for each field. The heart and right and left lung in each slice were contoured based on RTOG by oncologist and physicist, and was reconstructed in three dimensions by treatment planning system (Isogry version 4.1). Dose-volume histogram (DVH) for organs at risk were calculated and extracted. Parameters V5, V10, V20, V30, V40 and also Dmax and Dmean for organs at risk were extracted. Patients were classified into two groups, large and small breasts; then statistical analysis was performed with the SPSS software.
Results:
At all levels of the dose for the large breast group, a greater percentage of the heart was involved, but there was no significant statistical difference between the small breast group (p>0.05). In lungs, at all levels examined, the received dose of large breast group was higher than those of the small breasts, but this difference was not statistically significant (p>0.05). Only the Dmax parameter between the two groups was significant (p=0.01).
Conclusion:
The received dose of organs at risk, better results were obtained in a small breast; but no threshold of exposure risks. Therefore, paying attention to this group of patients is more clinically important. It is recommended that treatment planning for patients with large breast size more carefully done.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
261
261
https://ijmp.mums.ac.ir/article_12897_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12897
Optimization of a SPECT system for imaging of 90Y in liver using Monte Carlo method
Sedigheh
Jafari
Department of nuclear engineering, science and research branch, Islamic Azad University, Tehran, Iran
author
Asghar
Hadadi
Department of nuclear engineering, science and research branch, Islamic Azad University, Tehran, Iran
author
Jalil
Pirayesh Islamian
Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Mohammad
Khoshakhlagh
Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Farshid
babapoor Mofrad
Department of nuclear engineering, science and research branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: Acquiring a high quality image has assigned an important concern for obtaining accurate diagnosis in nuclear medicine. Detector and collimator are critical component of Single Photon Emission Computed Tomography (SPECT) imaging system for giving accurate information from exact pattern of radionuclide distribution in the target organ. The images are strongly affected by the attenuation, scattering, and response of the detector and collimator.
Method and material: The Planar and SPECT scans of a Y90 point source and also an extended Cardiac- Torso(XCAT) computerized phantom with the experiment and simulated systems were prepared. The SIMIND Monte Carlo program was used for simulating Siemen’s dual head variable angle SPECT imaging system with 4 detectors and 10 collimators. After verification and validation of the simulated system, the similar scans of the phantoms were compared from the point of view of image quality for 4 scintillator crystals including: NaI(Tl), BGO, LuAG: Ce, LaBr3 and also 10 collimators: Pb, Pb-Sb, Pb-Sb3, Pb-bi-Sn19, Pb-bi Sn375, Pb-bi-Sn50, Pb-bi-Sn-cd10, Pb-bi-Sn-cd125, Pt and Pt-Co. The parameters of energy and spatial resolution, and sensitivity of the systems were compared. Images were analyzed qualitatively by two nuclear medicine specialists.
RESULTS: FWHM of the mentioned crystals and collimators obtained where: NaI (Pb, 0.3853) and BGO (Pb-Sb, 0.406), (Pb-Bi-Sn375, 0.405), (Pb-Bi-Sn-cd125, 0.375), and LuAG: Ce crystal (Pb-Sb, 0.425), (Pb-
Bi-Sn19, 0.407), (Pb-Bi-Sn375, 0.417) and also LaBr3 (Pb-Bi-Sn375, 0.407), (Pb-Bi-Sn50, 0.430), (Pt-Co,
0.355). Medical diagnosis of the SPECT images of the phantom showed that the system with NaI(Tl)and LaBr3 by Pb-Sn3 collimator potentially provides a better detectability for hot lesions in the liver of XCAT phantom.
CONCLUSIONS: The results showed that crystal NaI(Tl)and LaBr3 by Pb-Sn3 collimator has a high sensitivity and resolution, and also provides a better lesion detectability from the point of view of image quality on XCAT phantom.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
262
262
https://ijmp.mums.ac.ir/article_12898_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12898
An Approach in Radiation Therapy Treatment Planning: A Fast, GPU-Based Monte Carlo Method
Mojtaba
Karbalee
School of Allied Medical Sciences, Zabol University of Medical Sciences, Zabol, Iran
author
Daryoush
Shahbazi Gahrouei
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Mohammad B.
Tavakoli
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
text
article
2018
eng
Introduction:
An accurate and fast radiation dose calculation is essential for successful radiation radiotherapy. The aim of this study was to implement a new graphic processing unit (GPU) based radiation therapy treatment planning for accurate and fast dose calculation in radiotherapy centers.
Materials and Methods:
A program was written for parallel running based on GPU. The code validation was performed by EGSnrc/ DOSXYZnrc. Moreover, a semi-automatic, rotary, asymmetric phantom was designed and produced using a bone, the lung, and the soft tissue equivalent materials. All measurements were performed using a Mapcheck dosimeter. The accuracy of the code was validated using the experimental data, which was obtained from the anthropomorphic phantom as the gold standard.
Results:
The findings showed that, compared with those of DOSXYZnrc in the virtual phantom and for most of the voxels (>95%), <3% dose-difference or 3 mm distance-to-agreement (DTA) was found. Moreover, considering the anthropomorphic phantom, compared to the Mapcheck dose measurements, <5% dosedifference or 5 mm DTA was observed.
Conclusion:
Fast calculation speed and high accuracy of GPU-based Monte Carlo method in dose calculation may be useful in routine radiation therapy centers as the core and main component of a treatment planning verification system.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
263
263
https://ijmp.mums.ac.ir/article_12899_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12899
Carbon Nanotubes as Near Infrared Radiation (NIR) Molecules for Cancer treatment
Mojtaba
Hoseini-Ghahfarokhi
Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Raziye
Fayazi
Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction:
The photo-thermal therapy by nanoparticles has been recently known as an efficient strategy for the cancer treatment. Carbon nanotubes (CNTs) have been extensively studied in biomedical application due to the easy uptake and high permeability in the cells, biocompatibility in biological environments and also their unique electrical, thermal properties. They generate significant amounts of heat through high absorption near- infrared light (NIR, 700-1100nm) which results in the death of cancer cells in non-invasive manner. This study reviews the effects of CNTs on cancer treatment and their toxicity in biological environments.
Materials and Methods:
In order to access related studies advanced search was done in the databases including Science Direct, Scopus, PubMed and google scholar with keywords “Carbon nanotube”, “thermal therapy”, “near-infrared light”. In addition, further studies were obtained by searching the references of each study. Among the articles, more related studies to the subject were selected and analyzed their results.
Results:
Among the papers, some studies have examined the effects of CNTs on cancerous cells In vitro or In vivo while some were performed in both models. Moreover, several studies have utilized active targeting by biological agents like tumor-specific antibodies or aptamers to enhance CNTs uptake. Additionally, the studies have reported the toxicity of the nanotubes depends on the type and surface characteristics of the nanotubes and the amount of injectable doses. However, the biocompatibility and non-toxicity effect of pure CNTs was also proven. Owing to high NIR absorption and converting it to heat, they increased radio- sensitivity and chemo-sensitivity of tumor cells significantly as well caused a decrease in tumor volume.
Conclusion:
CNTs are promising candidates for cancer treatment via thermal therapy. However, it seems more studies should be carried out on animal models in different conditions.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
264
264
https://ijmp.mums.ac.ir/article_12908_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12908
Optimization of tangential fields arrangement in the breast cancer 3D conformal radiation therapy
Mostafa
Robatjazi
Medical Physics and Radiological Sciences Department, Sabzevar University of Medical Sciences, Sabzevar, Iran
Vasei Radiotherapy & Oncology Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
author
Hamid Reza
Baghani
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
author
Pejman
Porohan
Vasei Radiotherapy & Oncology Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
author
Seied Rabi
Mahdavi
Medical Physics Department, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
The incidence of breast cancer increases with the rate of 1-2% at the world. Radiation therapy is one of the available choices for breast cancer treatment. The single isocentre half-beam block technique is considered as a standard technique to avoid hot and cold spots within the PTV. The major advantage of half beam technique is that the both contralateral breast and lung are completely spared. Also, using this technique, we don’t have any field matching problem. But, Lateral and medial movement of isocenter in conjunction of supraclavicular and tangential beams affect the divergence of tangential fields. Therefore, opposite tangential field can be parallel either in posterior border or beam central axis. The aim of this study is to compare the dosimetric parameters of three plans for tangential beams arrangement and select the optimal one.
Materials and Methods:
In this study, we selected 6 patients with breast cancer that underwent breast conserving surgery and considered for radiotherapy. CT simulation of patients were done based on standard protocols and imported to Isogray treatment planning system. Contouring of target volume and organs at risk (OARs) was done by radiotherapist. The tangential fields were considered in three different geometries of parallel in the posterior border with divergence in back jaws, parallel in central axis with divergence in back jaws and Parallel in posterior border without divergence of back jaws (half beam). Dosimetric parameters of each plan for OARs and target volumes extracted from DVHs data and compared statistically using ANOVA one-way repeated measurement test.
Results:
There was no statistical difference between dosimetric parameters (D95, V95, Dmax, and Dmean) of the target volume in three mentioned plans (P-value = 0.93). Although, there was no statistical difference between mean dose of the ipsilateral lung, the difference of V10 and V20 parameters for this organ is significant (P=0.01). Furthermore, there was no statistical difference in dosimetric parameters of OARs such as contralateral breast, lung, heart, and spinal cord.
Conclusion:
This study showed that back jaw divergence and arrangement of parallel opposite field can affect the ipsilateral lung dose. The V20 and V10 of ipsilateral lung are two dose constraints parameters in quantitative treatment planning evaluation of breast treatment. Quantitative variations of these parameters with changing the tangential field’s arrangement was significant which depends on the isocenter position and back jaw divergence. The values of these parameters were the highest when tangential fields were arranged as parallel in posterior border with divergence in the back jaw.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
265
265
https://ijmp.mums.ac.ir/article_12909_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12909
Cabazitaxel antiproliferative mechanism of action in U87MG human glioblastoma cells: a promising cell-cycle phase-specific radiosensitizer
Ali
Neshasteh-Riz
Radiation Biology Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran
Cellular and Molecular Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
Elham
Zeinizade
Radiation Biology Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran
Cellular and Molecular Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
Majid
Safa
Cellular and Molecular Research Center, Iran University of Medical Sciences (IUMS), Tehran, Iran
Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
Kazem
Mousavizadeh
Cellular and Molecular Research Center and Department of Molecular Medicine, Faculty of Advanced Technologies in Medicine, Iran, University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
One mechanism of cell cycle manipulation and mitotic catastrophe is arrest at G2/M phase of cell cycle. Cabazitaxel, a mitotic inhibitor agent, is a second-generation semisynthetic taxane. An expected anti-neoplastic effect of Cabazitaxel is cell cycle perturbation and alteration of microtubule dynamics. In contrast to other taxane compounds, Cabazitaxel is a poor substrate for P-gp efflux transporters, hence, penetrates easily across the blood brain barrier (BBB). In the present study, we investigate its distinct antiproliferative mechanism of action and radiosensitizing potential against U87MG glioblastoma cells.
Materials and Methods:
In order to evaluate the effect of Cabazitaxel, cells were treated with different concentrations of the drug at different time points and then cytotoxicity and cell cycle were assessed using MTT and flow cytometry assays, respectively. Comparison of induced apoptosis and necrosis in population of cells was depicted by Annexin/PI assay. In order to investigate the expression of genes involved in apoptosis real-time polymerase chain reaction (PCR) method was used.
Results:
A consistent G2/M arrest was exerted by Cabazitaxel. The drug resulted in a concentration- and time-dependent toxicity and a shap decline in cell viabiliity. EC50 and IC50 in cells treated with Cabazitaxel for 24 hours exactly approved each other. The cytotoxicity response of U87MG cells increased following Cabazitaxel-IR administration. On the other hand, IC50 of Cabazitaxel-IR in comparison with 24 or 48 hours treated cells showed a significant decrease. Concurrently, these observations were further supported by up regulation of pro- apoptotic genes and down regulation of anti-apoptotic genes.
Conclusion:
To our Knowledge, no straightforward explanation thus far has addressed the effect of Cabazitaxel applied before radiation on U87MG cells. This report provides the first preclinical evidence supporting that Cabazitaxel can render cells more susceptible to the cytotoxicity of radiation and potentiates the effect of RT. In the near future, Cabazitaxel could potentially be administered in combination modalities as a potential therapeutic compound and also promising cell cycle-specific radiosensitizer to stall tumor growth.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
266
266
https://ijmp.mums.ac.ir/article_12910_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12910
Determination of Diagnostic Reference Level in routine Computed radiography examination in north of Iran
Roya
Bordbar
Msc Student of Medical Physics Radiobiology and Radiation Protection Department, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Ali
shabestani Monfared
Professor of Medical Physics, Department of Medical Physics Radiobiology and Radiation Protection, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Mohammad Reza
Deevband
PHD of Medical Physics, Department of Medical Physics and Engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Fatemeh
Niksirat
MSc of Medical Physics Radiobiology and Radiation Protection Department, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Kourosh
Ebrahimnejad Gorji
PHD of Medical Physics, Department of Medical Physics Radiobiology and Radiation Protection, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
text
article
2018
eng
Introduction:
Digital radiography has a major role in nowadays healthcare system so radiation protection (justification and optimization) is important in this field. Many related organizations to protection suggested to establish national and regional diagnostic reference level for medical procedures. Reference levels are typically set at the 75th percentile of the dose distribution from a survey conducted across a broad user base using a special dose measurement protocol and phantom. This study aimed to establish diagnostic reference level for computed radiography examination in north of Iran.
Materials and Methods:
The data were collected from 7 public hospitals for 12 computed radiographies routine examination including: skull (AP-LAT), cervical (AP-LAT), chest (PA –LAT), thoracic (AP- LAT), lumbar(AP-LAT), abdomen(AP) and pelvis (AP). For each projection, 10 patients at least 18 years olds were investigated. The study was performed by filling out the questioner which was contained the following parameters: Center name, machine manufacturer, Type of Examination, Tube Voltage (kVp), Current Time Product (mAs) and Film Focus Distance (FFD). The quantity of entrance skin dose is evaluated by measuring ESD. The third quartile of ESD related to each projection was considered as DRL of that examination.
Results:
Based on the data of this study, we expected that diagnostic reference level of computed radiography examination in north of Iran is in accordance with standard values that were suggested by regulatory organizations such as American College of Radiology (ACR)and European Commission (EC).
Conclusion:
The comparison of the results of this survey with surveys performed in other countries will indicate the protection level of patients in computed radiography examination in north of Iran.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
267
267
https://ijmp.mums.ac.ir/article_12911_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12911
Independent assessment of source transit time for the BEBIG SagiNova® high dose rate brachytherapy afterloader
Abolfazl
Kanani
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
Student research committee, Shiraz University of Medical Sciences, Shiraz, Iran
author
Sareh
Karbasi
Physics Unit, Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad Amin
Mosleh-Shirazi
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
Physics Unit, Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction:
The dwell time and transit time components contribute to the overall delivered dose to patients in high dose rate (HDR) brachytherapy treatments. The transit time results from source entry and exit as well as source movements between dwell positions. It depends on various parameters such as the source speed profile, source indexer distance to dwell position, and step size. Usually brachytherapy treatment planning systems do not apply a correction for transit time and the afterloader unit itself adjusts the final dwell times taking account of the transit time. The independent verification of transit time for each HDR afterloader is recommended before clinical use. Some published reports have used a video camera and/or stopwatch to perform this task. To the best of our knowledge, there is no published report of transit time measurement for the recently released BEBIG SagiNova® HDR afterloader unit. The goal of this study is to independently evaluate the corrected source transit time of this afterloader unit without using a video camera or stopwatch.
Materials and Methods:
The assessed unit was a newly installed SagiNova® 60Co HDR afteroloader (software version 1.2.4; Eckert & Ziegler BEBIG GmbH). A dosimetric method was used. The measurements were performed using a previously commissioned PTW source check4п (type 33005) well- type ionization chamber and UNIDOS E® electrometer. A 30 cm plastic needle and a 100 cm transfer tube were used to accurately place the source at the point of maximum response (‘sweet spot’) of the well chamber. Plans were generated using SagiPlan version 2.0 to irradiate the well chamber for dwell times of 3, 5, 10, 15, 20, 30, 40, 60, and 120 s. All the measurements were repeated three times. The transit time following its correction by the afterloader software were assessed using the ESTRO-recommended approach of obtaining transit time correction factors and another strategy established for teletherapy sources. The results obtained using the two strategies were also compared.
Results:
For the measured setup, the transit time was 0.7 s using both methods. The mean ESTRO transit time correction factor was 0.93 (range 0.88 to 0.99 for dwell times of 3 to 120 s).
Conclusion:
This work demonstrates an accurate dosimetry-based method to measure source transit time during the commissioning step of HDR BT afteroloaders, using a practical approach and available standard equipment. It also shows the consistency of the results between the two dosimetric methods of obtaining source transit time. The results suggest that the afterloader software correction does not completely eliminate this effect, which results in slightly longer
irradiation times.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
268
268
https://ijmp.mums.ac.ir/article_12912_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12912
Conventional Voxel in Tomographic Reconstruction Based upon Plane-Integral Projections – Use It or Lose It?
Hojjat
Mahani
Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
author
Gholamreza
Raisali
Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
author
Alireza
Kamali-Asl
Radiation Medicine Department, Shahid Beheshti University, Tehran, Iran.
author
Mohammad Reza
Ay
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: While the necessity of replacing voxels with blobs in conventional tomographic reconstruction based upon line-integrals is clear, it is not however well-investigated in plane- integral-based reconstruction. The problem is more challenging in convergent-plane projection reconstruction. In this work, we are aiming at utilizing blobs as alternative to voxels.
Materials and Methods: To doing so, a spinning slithole collimated small-animal SPECT scanner was modeled within GATE simulator and SPECT data acquisition was performed for NEMA IQ phantom. The slithole provides convergent-plane-integral projections of the object being imaged. The collimation data were then reconstructed using an ad hoc 3D OSEM algorithm based upon plane-integral projections using cubic voxels. The image reconstruction was repeated for blobs. Various figures of merit were assessed in order to compare voxel and blob reconstructions.
Results: Both voxel and blob reconstruction algorithms were verified using a noisy 3D Shepp- Logan phantom prior to reconstructing the simulation data, with an error of 6% and 9%, respectively. Blob modeling leads to a lower computation burden by a factor of ~2.1 in on- the-fly calculation of the system matrix. A 13% increase in SNR of the hottest rod of the NEMA IQ phantom is obtained when voxels are replaced by blobs. Blob reconstruction shows an advantage over voxel reconstruction by offering a monotonically decreasing NSE across all iterations indicating a more robust statistical noise handling.
Conclusion: Voxels are simple and easy-to-implement, but blobs outperforms them by exhibiting a much more efficient projector/backprojector pair due to their inherent symmetric and smooth shape. Therefore, blobs should be the basis functions of choice in the case of plane-integral-based reconstruction.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
269
269
https://ijmp.mums.ac.ir/article_12913_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12913
Evaluation the function of Sanandaj Tohid radiotherapy center in the treatment of glioma tumors using MRI during 2009-2016
Sohaila
Yazdani
MSc of Medical Physics, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Sohrab
Sakinehpor
BSc of Radiotherapy, Research Committee, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Amir
Nami
Radiation Oncology Specialist, Tohid Hospital, Radiotherapy Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Mehran
Yarahmdi
Assistant Professor, Department of Medical physics, Kurdistan University of Medical Sciences, Sanandaj, Iran, (Corresponding Author), Tel:+98-87-33611045, yarahmadi.mp@gmail.com
author
text
article
2018
eng
Introduction:
Glioma is the most common type of primary brain tumor that originates from glial tissues. These types of tumors have a high degree of malignancy and poor prognosis and low survival rates. The evaluation response to treatment is essential to decide whether present treatment is adequate or need for alternative therapy. The aim of this study was to evaluate the response of glioma tumors to the treatment by using of MRI in patients undergoing radiation therapy. Which leads to an assessment of the function of the radiation therapy center in the treatment of this type of tumor.
Materials and Methods:
The 190 patients with glioma tumor who referred to Tohid Radiotherapy Center of Sanandaj were studied during the years of 2009 to 2016. The response rate to radiation was evaluated by using the MRI images with contrast based on the enhanced Gadolinium. Data were analyzed using SPSS 20 software
Results:
The incidence rate of the men was 1.6 times of the women. The most frequent type of tumor was related to GBM tumors by %51.6. The analysis of MRI images showed that in 161 cases
- approximately 85% - the tumor responded to treatment and the treatment was successful.
Conclusion:
In this group of patients is often due to the sensitivity of the anatomical location of the tumor, there is no possibility of surgery, and they are resistant to chemotherapy because of the blood-brain barrier. Therefore, radiotherapy plays a key role in the treatment of this type of tumor. According to follow-up with MRI- a noninvasive method that can provide information to the anatomical, physiological and molecular- the function of the radiation therapy center acceptable is evaluated for the treatment of these patients.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
270
270
https://ijmp.mums.ac.ir/article_12915_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12915
Effect of Physiological noise on Thoraco-Lumbar spinal cord fMRI in 3T Magnetic field
Hamed
Dehghani
Department of Medical Physics and Biomedical engineering, Tehran University of Medical Sciences, Tehran, Iran,
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Mohammad Ali
Oghabian
Department of Medical Physics and Biomedical engineering, Tehran University of Medical Sciences, Tehran, Iran,
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Amir Hossein
Batouli
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Ali
Khatibi
McConnel Imaging Center, Montreal Neurological Institute, McGill University, Quebec, Canada
author
text
article
2018
eng
Introduction:
Functional MRI methods have been used to study sensorimotor processing in the brain and
the Spinal cord. However, these techniques confront unwanted contributions to the measured signal from physiological fluctuations. For the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as significant sources of noise. Spinal cord in Thoraco-Lumbar is close to lungs and diaphragms that influence cerebrospinal fluid-filled spaces and cause changes in thesusceptibility due to the change in the amount of air in the lung. In this study, we investigatedthe effect of each source of physiological noise and contribution of them to the outcome ofthe analysis of the BOLD signal in human spinal cord during a sensory stimulation of the foot.
Materials and Methods:
Fifteen young healthy male volunteers participated in the study. Sixty pressure pain stimuli
delivered on L5 dermatome between the two malleoli. All of functional data were collected
using a 3T Siemens Prisma scanner with 31 axial slices T2*-weighted ZOOMit (TR = 3000 ms;
TE = 30 ms; FA = 90°; FoV = 160 × 160 mm; matrix size = 64 × 64). Respiratory and cardiac
signals were recorded during the imaging session using the data acquired from theimplemented physiological monitoring unit. The Spinal Cord Toolbox and FSL were used forimage processing and analysis. Generated respiration and cardiac regressors were includedin the GLM for the quantification of the effect of each of them on the task-analyses results. The sum of activated voxels of the clusters in the spinal cord and in all the image was
calculated.
Results:
Comparison of sum of activated voxels. A one-way within subject’s ANOVA was applied toevaluate the effect of physiological functions on spinal cord fMRI in three noise correction inthe GLM. There was a statistically significant effect of physiological noise correctiononnumber of activated voxels in Image, F (3, 42) = 3.00689, p = .040817, η2 =0.17, and thisvalues in spinal cord was F(3, 42) = 21.314, p =.00001, , η2 =0.6. Bonferroni post hoc testsillustrate that cardiac noise correction had an effective role on increase activated voxels
(mean = 23.46±9.46) compared to other noise correction methods.
Conclusion:
The effect of the Heart-beat and Respiration movements has a significant role in thephysiological noise and concurrency between movements with task and correction of thismovements can remove the real effect of stimulation. Cardiac effect and changes in thecorrected results are higher than other physiological noise sources. In spite of previous work,displacement of the spinal cord and effect of this noise in the fMRI results are significant andcannot be ignored.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
271
271
https://ijmp.mums.ac.ir/article_12918_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12918
Optimized co-registration method of Spinal cord MR Neuroimaging data analysis and application for generating multi-parameter maps
Hamed
Dehghani
Department of Medical Physics and Biomedical engineering, Tehran University of Medical Sciences, Tehran, Iran.
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Mohammad Ali
Oghabian
Department of Medical Physics and Biomedical engineering, Tehran University of Medical Sciences, Tehran, Iran.
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Amir Hossein
Batouli
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Ali
Khatibi
McConnel Imaging Center, Montreal Neurological Institute, McGill University, Quebec, Canada
author
text
article
2018
eng
Introduction: The purpose of multimodal and co-registration In MR Neuroimaging is to fuse two or more sets images (T1, T2, fMRI, DTI, pMRI, …) for combining the different information into a composite correlated data set in order to visualization, re-alignment and generating transform to functional Matrix. Multimodal registration and motion correction in spinal cord MR Neuroimaging data, often performed using affine and rigid transformations constrained in the axial or sagittal plane. However, since spinal cord geometry is articulated and respiration is a cause of slice-wise related shifts along the phase-encoding direction, non- rigid registration has been proposed. We tested a number of options for registration of multi- parameter spinal cord data (functional EPI/FSE data and Anatomic T2 SPACE). A result of the registration process is used to fuse information of MRI and fMRI and our technique that based on an efficient non-parametric image registration could be done in a semi-automated fashion, and alignment to the template cord performed using.
Materials and Methods: For a single subject, the functional MRI data set (EPI/T2*, FSE/T2) and diffusion (EPI) have been registered with anatomic images and standard space by multi- modal non-parametric registration algorithm. This algorithm is performed with different cost function (mutual information, normalized correlation, and least-square) and slice regularization along with cord. Registration results are compared two kinds of similarity measures; mutual information (MI) and correlation ratio (CR). To evaluate the performance of non-parametric technique, anatomical regions (Cervical and Lumbar spine) and image qualities, data were acquired in 18 data-set include Axial EPI-fMRI (TE/TR: 125/1250 mS, Matrix: 128×128), Sagittal FSE-fMRI (TE/TR: 76/750 mS, Matrix: 256×256). We used random Gaussian noise for two FSE dataset for exam our technique.
Results: Numerical measurements of the different cost function and slice regularization method for the sagittal FSE-fMRI and Axial GRE-EPI-fMRI data have been shown average MI=796.2, CR=0.73 for non-parametric and MI=864, CR=0.81 for multi-modal registration with normalized correlation + slice regularization. It can be concluded that the MI cost function produces better results when the images have good quality and the normalized correlation measure is more suitable for noisy images.
Conclusion: The optimized co-registration that was used is based on the slice by slice regularization along with the spinal cord in the spatial domain. Two similarity measures; correlation ratio and mutual information were used and results were compared with the results of the different measures of non-parametric registration. It was shown that for human MR Neuroimaging data the multi-modal non-parametric registration with normalized correlation cost function + regularization produces better results in terms of accuracy and time compared to parameters in the co-registration for both similarity measures. Also, it was shown that for noisy Sagittal FSE/fMRI images better registration results are produced when normalized correlation is used as the similarity measure.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
272
272
https://ijmp.mums.ac.ir/article_12920_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12920
Evaluation of Sensory Pathways in Spinal Cord by Comparison of fMRI Methodologies
Hamed
Dehghani
Department of Medical Physics and Biomedical engineering, Tehran University of Medical Sciences, Tehran, Iran
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Mohammad Ali
Oghabian
Department of Medical Physics and Biomedical engineering, Tehran University of Medical Sciences, Tehran, Iran
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Amir Hossein
Batouli
Neuro-Imaging and Analysis Group (NIAG), Tehran University of Medical Sciences, Tehran, Iran.
author
Ali
Khatibi
McConnel Imaging Center, Montreal Neurological Institute, McGill University, Quebec, Canada
author
text
article
2018
eng
Introduction:
Today, clinicians and neuroscientists need to have a comprehensive survey of neurological pathologies and injuries. For the First-time, SEEP contrast and Spin-Echo pulse sequences was used for functional imaging of the Lumbar spinal cord. This method used by several research groups for Spinal cord mapping, but other researchers tried to improve BOLD fMRI to Spinal cord imaging simultaneously. Here, we present a comparison between useful imaging methods and finally use of certain procedure for Spinal cord mapping with sensory stimulation.
Materials and Methods:
We planned two imaging protocols on Siemens 3T magnetom trio scanner: HASTE/SSFP, TE/TR: 76mS/6750mS for 9 sagittal slices with 2 mm thickness, FOV= 280×210mm, and Gradient Echo EPI, TE/TR: 30S/3000mS for 21 axial slices with 5mm thickness, FOV= 64×64mm. These image acquisition procedures performed on All 5 subjects (male, Age: 24.6±2.05), stimulated by 60g von Frey filament. Stimulations were used in the block design, 8 blocks with time 40.5 S for SE protocol and 42 S for GRE protocol and performed on right foot L4 dermatome. We entered each subject’s data sets into an individual first-level statistical analysis. Then we calculated signal changes in the mask that generated in the statistical analysis and amount of temporal Signal to Noise Ratio (tSNR). Other subjects group (5 males, Age 25.3±1.5) was imaged with same protocol as GE-EPI and T2W anatomic images (3D-FSE Isotropic, TR/TE:1500/430 ms, FOV= 256×60 mm, slice-thickness: 1mm). Data sets were processed with GLM and Finally, all first-level analysis results are entered in Higher-level analysis as group analysis and obtained statistical maps for spinal cord functions.
Results:
We observed different tSNR in two separated datasets, 2.619 ± 0.440 for SE-HASTE images and 4.901 ± 0.762 for GRE-EPI. After statistical analysis of images and obtaining signal change in the spinal cord. We comprised them and measured signal change was 1.737 ±
1.252 for SE-EPI and 2.554 ± 1.327 for GE-EPI. Based on these results we decided to use GE- EPI for spinal cord functional imaging. We stimulated L4 dermatome and this localized activation was observed in the T9-T1. The activation maps show ipsilateral synapse and tracks in the dorsal higher than ventral horn.
Conclusion:
At the first step evaluation of imaging methods show GRE-EPI can more efficient for Lumbar functional MRI and detection of BOLD signal change in the spinal cord. This research demonstrates the benefits of spinal cord fMRI for mapping of sensory stimulation. The resulting activity maps show primarily in ipsilateral dorsal regions and in some ventral regions, consistent with the spinal cord anatomy. These data also illustrate details of the sensory organization of the spinal cord, as well as anatomical detail of the spinous processes and positions of nerve roots.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
273
273
https://ijmp.mums.ac.ir/article_12921_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12921
Small field size dose-profile measurements using MAGIC- f polymer gel dosimeter and EBT3 film dosimeter
Saeede
Amiri
Medical Physics and Biomedical Engineering Department, Shahid Beheshti University of Medical sciences, Tehran, Iran
author
Ahmad
Mostaar
Medical Physics and Biomedical Engineering Department, Shahid Beheshti University of Medical sciences, Tehran, Iran
author
Mohammad
Houshyari
Radio-Oncology Department, ShohadaeTajrish hospital, ShahidBeheshti University of Medical sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: In radiotherapy, treatment planning methods are evaluating and transforming every day, so precision in calculation and determination of dose delivery process is performing more important role in radiotherapy than past. In modern radiotherapy treatments, deramatically increase of small fields utilization, causes the polymeric gels has known as the most reliable dosimeter for this kind of fields. Polymer gel dosimeters contain radiation sensitive materials that are irradiated as a function of polymerized absorbed dose, and the spatial information of the radiation dose distribution is extracted by imaging the irradiated gel. In this study, the polymeric system dosimeters performance MAGIC-f gel which obtained from the MRI imaging method, were compared with the EBT3 film dosimeter.
Materials and Methods: A polymer gel type called MAGIC-f was applied in this study is as the same as type of polymer used in Fernandes et al study. After preparing the required gel and pouring it into phantoms and calibration tubes, they were irradiated with 6 MV photon beam, then dose distribution R2 maps were obtained by (3T MRI) taking MR images of them. Dicom images and necessary parameters were extracted by MATLAB and imagej software. The dose-profile was measured for three small field size (5,10,15 mm diameters) by using polymer gel compared with results of the EBT3 film dosimetry.
Results: With Comparing the obtained results of two dosimeters, the maximum difference between the measured profiles was observed in penumbra areas (out of range). In these regions, the penumbra which measured by MAGIC-f was almost 1 mm larger than the measured width of penumbra by EBT3 film dosimeter. The maximum variation was seen in the flat area (isodose 90%) of the 0.5×0.5 cm2 dose profile curve was 4.68%. In the 1×1 and 1.5×1.5 cm2 fields, the greatest difference in the flat area of dose profile curve was 3.04% and 4.48%.
Conclusion: In summarize MAGIC-f gel is more convenient and stable dosimeter than film for small fields studies. Moreover, it has a substantial potential for utilization as a 3D dosimeter in clinical applications of radiation therapy. Differences in the cross-sectional dose profile curves between polymer gel dosimeters (MAGIC-f) and film EBT3 can explain by various factors, such as way of preparing gel, materials quality which used in gel composition, and the quality of the imaging system.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
274
274
https://ijmp.mums.ac.ir/article_12922_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12922
Study of cancer cells response row K562 to Low-Dose- Beta irradiation and determination of absorbed dose using Monte Carlo method
Seyed Mostafa
Mohammadi
Departments of Physics, Faculty of Science, Urmia University, The west azaarbayjan, Iran
author
Zeynab
Alizadeh
Departments of Physics, Faculty of Science, Urmia University, The west azaarbayjan, Iran
author
Rasoul
Khodabakhsh
Departments of Physics, Faculty of Science, Urmia University, The west azaarbayjan, Iran
author
text
article
2018
eng
Introduction: Cancer is, in essence, a genetic disease and is the second leading cause of death globally. Fortunately, many common types of cancer are treatable if detected early and of course there are many medications and treatments available today. Among the new methods to treat cancer, radiotherapy seems to be hopeful in patients with malignancies. This work investigates the strontium beta irradiation (90Sr) dose response on the clonogenicity of Animal blood cancer cell row K562. Scope of this work is the survey of cells survival for three time periods of irradiations and calculating absorbed doses of cancer cells by Monte Carlo simulation.
Materials and Methods: The K562 cells were cultured and irradiated with β-particle emitted from 90Sr, daily 30 minutes, 1 hour and 2 hours for 3 days. Cells survival was evaluated by three methods of MTT assay, cell visual survey and DNA electrophoresis after irradiation. To compare the results of cells survival after irradiation, determination of absorbed dose of cancer cells is necessary. But, the short ranges of the emitted beta particles and the associated large dose gradients make experimental measurements particularly difficult. In this circumstance, we have motivated by using of Monte Carlo simulation techniques. To calculate absorbed doses of cancer cells via Monte Carlo, the problem was simulated with MCNP code. Of course, to verify results of simulation with results experimental, we used a Geiger Muller counter and estimated a Scaling Factor.
Results: cell visual survey presents photomicrographs of blood cancer cells sections indicating the number of the survive cells after irradiations. Survival percent were obtained for three time periods of irradiations in MTT assay. The survival of cells was described as a function of dose and these absorbed doses were determined using MCNPX code. Finally, to recognize that The cells death was been only due to the destruction of the cell membrane, or the irradiation affect DNA and break it, we did DNA electrophoresis assay.
Conclusion: Cell visual survey indicates the positive effectiveness of beta particles on cancer cells. Also, Comparing the survival curves, that hypersensitivity component and dose rate effects are small or absent in high LET, we estimated α component. Eventually, checking the DNA electrophoresis, we understood that in very low-dose- rate up to 2.213±0.0015cGy, cells death Arises from destructing the cell membrane but form 2.213±0.0015 cGy to top, ray begin to effect on DNA.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
275
275
https://ijmp.mums.ac.ir/article_12924_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12924
Calculation of air gaps between bolus and skin on the dose received from the skin
Mohammad Ali
Ostadrahimi
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Ghazaleh
Sadrieh Khajoo
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Ahmad
Mostaar
Medical Physics and Biomedical Engineering Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mahdi
Salehi Barough
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: In the last few decades, a lot of monte carlo codes have been introduced for medical applications. For close - to - surface tumors, the surface of the skin can be used to increase the surface dose so that all or part of the bunch area can fall into bolus, thereby increasing the dose of the skin.
The air gaps between bolus and skin can affect the dose of skin, especially if the skin is only the target of treatment.
For this purpose, the effect of energy, bolus thickness, the amount of air gap, field dimensions and angle of field contact angle will be evaluated.
Materials and Methods: In this study, the MCNPX calculation code is used to simulate the linear accelerator of Siemens to determine the effects of air gaps between bolus and skin.
The studied fields were chosen in this study with dimensions 4×4 and 10×10 cm2. it also simulated a water phantom at SSD=100 cm and bolus thickness 0.5,1 cm in distances 0, 0.5 cm.
Results: For field sizes 4×4 cm2 with 6 photon beam The bolus was as thick as 0.5 cm in the distance of 0 and 0.5 cm from the phantom level with a percent of surface dose to the maximum dose in the absence of the air gaps with %104.615 in the presence of air gaps
%101.866 and the bolus thickness of 1cm in a same distance from the phantom level with a percent of surface dose to the maximum dose in the absence of the air gaps with %106.89 in the presence of air gaps %100.47. Also for field sizes 10×10 cm2, thickness of 0.5 cm in distance of 0 and 0.5 cm, from the phantom level with a percent of surface dose to the maximum dose in the absence of the air gaps with %99.62 in the presence of air gaps %97.74.
Conclusion: For field size 10×10 cm2 Dsurf is largely unaffected by air gaps. However, smaller air gap results in shallower dmax for 6 MV photon beams at all fields sizes. Special consideration should be taken to reduce air gaps between bolus and skin for field sizes smaller than 10×10 cm2 or when surface contour variations are greater or when the bolus covers small area and at the border of the field.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
276
276
https://ijmp.mums.ac.ir/article_12925_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12925
Calculation the phantom scatter factor for the linear accelerators device
Ghazaleh
Sadrieh Khajoo
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Mohammad Ali
Ostadrahimi
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Ahmad
Mostaar
Medical Physics and Biomedical Engineering Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mahdi
Salehi Barough
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: In the last few decades, a lot of monte carlo codes have been introduced for medical applications. this is important because through simulation, we are fully independent of the spectral scattering factor that we are not able measure in real terms. The effect of the radiation energy, the dimension of the radiation field, the sensitive volume of the ion chamber on the scene of the phantom scattering factor.
Materials and Methods: In this study, the MCNPX calculation code was used to simulate the Siemens linear accelerators to determine the measure of phantom scatter factor.
The studied fields were chosen in this study with dimension 3×3, 10×10 and 20×20 cm2.
It was also simulated to examine dosimetry parameters including deep dose curves and dose distribution for 6 and 15 MeV, a water phantom at SSD=100 cm in order to measure the phantom scattering factor and a total scatter factor and a build-up cap in order to measure the collimator scatter factor at SAD=100 cm.
Results: For field sizes 3×3 cm2 with 6 MV photon beams, the phantom scatter factor 0.9398, collimator scatter factor 0.8907 and the total scatter factor 0.8366, and also for the field sizes 20×20 cm2 with 6 MV photon beams, the phantom scatter factor 1.023, collimator scatter factor 1.0259 and the total scatter factor 1.0492 were calculated from monte carlo simulation.
The Experimental values are equal to this 0.9398×0.8907=0.8370 for field sizes 3×3 cm2 and 1.023×1.0259=1.0494 for field sizes 20×20 cm2.
All of the above values are normalized to field sizes 10×10 cm2 in 6 MV photon beams.
Conclusion: Due to the results obtained, the sensitive volume of the ion chamber is affected by the smaller than 10×10 cm2.
It has also obtained phantom scattering factor independently and verified with the S(c,p) = Sc × Sp relation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
277
277
https://ijmp.mums.ac.ir/article_12926_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12926
Detection of Glioblastoma Multiforme Tumor in Magnetic Resonance Spectroscopy Based on Support Vector Machine
Ayuob
Faramarzi
Department of Biomedical Engineering, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Armin
Allahverdy
Radiology Department, Allied Faculty, Mazandaran University of Medical Sciences (MazUMS), Sari, Mazandaran, Iran.
author
Mahmood
Amiri
Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Meysam
Siyah Mansoory
Department of Biomedical Engineering, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: The brain tumor is an abnormal growth of tissue in the brain, which is one of the most important challenges in neurology. Brain tumors have different types. Some brain tumors are benign and some brain tumors are cancerous and malignant. Glioblastoma Multiforme (GBM) is the most common and deadliest malignant brain tumor in adults. The average survival rate for people with this type of brain tumor is about 15 months. Brain tumors are more common in men and are more dangerous. The most important diagnostic modality for tumor detection is magnetic resonance imaging (MRI). MRI is a non-invasive diagnostic method that provides anatomical images of the tumors. In recent decades, advanced MRI techniques have been increasingly developed to better tumor detection. One of these methods is Magnetic Resonance Spectroscopy (MRS) imaging. The MRS technique is used to study human brain metabolites and evaluate the neurochemical profile of the brain tissue. Unlike the MRI, MRS is able to grade the tumor. Depending on the grade and metabolites of the tumor, MRS can complement MRI images in medical diagnoses. The purpose of this study is to use machine learning to discriminate between normal and tumorous voxels in MRS data which can lead to a reduction in human error in the diagnosis of neurologist, radiologist, neuroscientists and etc.
Materials and Method: According to the neurologist's comment, magnetic resonance spectroscopy imaging was performed on 7 patients with GBM at the imaging center of Imam Khomeini Hospital in Tehran. The radiologist labeled all the tumor and normal voxels. Preprocessing step, including baseline correction and water suppression was performed by TARQUIN software. In processing step, signals of each voxel were extracted and the concentration of the metabolites was calculated. For classification of normal and tumorous voxels, Support Vector Machine was done using Statistics and Machine Learning Toolbox by MATLAB software.
Results: For classifying the data, the support vector machine (SVM) was used. The results of classifiers showed 87% accuracy, 82% specificity and 93% sensitivity. For classify these data, the Gaussian kernel was used. Using the linear kernel, the accuracy obtained 63%, specificity obtained 56% and sensitivity obtained 68%.
Conclusion: The results showed that, the accuracy for SVM with Gaussian kernel is significantly higher than SVM with linear kernel. This result shows that; this dataset may have nonlinear distribution. Therefore, the nonlinear classifiers may show better results than linear classifiers.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
278
278
https://ijmp.mums.ac.ir/article_12927_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12927
Validation of treatment planning system using simulation PRIMO code.
Tahereh
yazdpour parizi
M.Sc., Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mahdi
Mommennezhad
PhD, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
author
Shahrokh
Naseri
PhD, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mahdi
Jamali
M.Sc., Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
Introduction: In radiation therapy, in order to double-check the dosimetric results of the main treatment planning system (TPS), a distinct TPS, with few capacitances in terms of contouring and a variety of dose calculation algorithms is used. This system has the capability to double check the planification and the accurate prediction of dose distribution in order to be ensured of the accuracy of the primary TPS results. The purpose of this study was to investigate the performance of Monte Carlo based algorithm, PRIMO, to double check the primary treatment planning software, and resolving the problem of limited budgets of radiotherapy centers in purchasing such systems. The present study evaluate the validation of the PRIMO code, in simulation of conformal treatments, which was performed with an Elekta Precise linear accelerator and an ISOgray treatment planning system.
Materials and Methods: In this study, the PRIMO code version 0.3.1.1626 was used. This code contains the geometry of Eleckta, Varian, Siemens linear accelerators and also CyberKnife system. The CT images of the Alderson Rando phantom, and the slab water phantom, contouring and treatment planning including photon energy, treatment fields and dose prescription point which was taken from ISOgray system in Dicom format were inputs of the PRIMO software. DICOM Editor Tools was used to solve the possible problems in reading these dicom files. To accelerate the simulation, the phase space files of a 6 MV photon beam derived from the International Atomic Energy Agency (IAEA) database.
Results: The gamma criteria of 3%/. 3 was used to compare the calculation results the simulation PRIMO code with ISOgray TPS system.
Conclusion: The results of this study indicate the potential of the PRIMO code for treatment planning in radiation therapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
279
279
https://ijmp.mums.ac.ir/article_12928_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12928
Investigation of dosimetric characteristic of NIPAM polymer gel using x-ray CT
Zeinab
Sattari
Medical Physics and Biomedical Engineering Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Ahmad
Mostaar
Medical Physics and Biomedical Engineering Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mohammad
Houshyari
Radio-Oncology Department, ShohadaeTajrish hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Polymer gel dosimeters contain chemical materials sensitive to the radiation which are polymerized by the radiation as a function of absorbed dose. So information of spatial dose distribution can be extracted by imaging from irradiated gel. Among imaging techniques, computed tomography (CT) poses as an attractive method because of practical advantages such as accessibility, easy and speed of image acquisition and dose-response is stable and relatively insensitive to environmental factors. The most major limitation that prevents this method from clinical application is high noise in images that obtained from this system. In this study, imaging parameters in purpose of noise reduction of CT image and then concentration impact of each component of NIPAM gel on dose-response have been investigated. Finally, imaging appropriate parameter for read-out gel and NIPAM gel composition with maximum dose sensitivity for X-ray CT imaging of gel are introduced which would be an attempt to facilitate the application of this method in clinical applications. Materials and Methods: NIPAM gel was made according to the method described by Chain et al.; after the preparation, they were poured inside the vials and retained in refrigerator at 4° C for 24 hours. After this stage, gel-contained vials were subject to irradiation with a cobalt- 60 machine in dose ranging 0-50 Gy. After this, the irradiated gels were imaged with the CT scan. Ultimately, resultant DICOM images were processed in MATLAB and CT mean value of the vials as well as corresponding standard deviation were taken. Results: In this study, the imaging protocol for the Siemens SOMATOS PLUSE 4 CT scanner was investigated to reduce image noise. Parameters of 140 kV, 206 mAs, 5 mm slice thickness and 10AH kernel-based reconstruction are suitable options to evaluate polymer gel using aforementioned device. A number of 25 images for averaging could reduce the noise to an acceptable level. NIPAM polymer gel with 5% gelatin, 10 mM THPC, 17% NIPAM monomer and 3% BIS indicates the biggest changes in the CT value at 0-50 Gy ranging dose for CT imaging method. Conclusion: high-percentage monomer NIPAM polymer gel shows high sensitivity to CT imaging method and has good reproducibility and linear response range; as well as since appropriately choosing imaging protocols and thus achieved image processing reduce the noise to an acceptable level, standing these factors along with applicable advantages of CT method such as accessibility in radiotherapy centers, ease and speed of the image provision, as well as being low-cost exhibits that NIPAM polymer gel dosimeter with CT imaging method has a good potential to become a three-dimensional dosimeter in radiation therapy clinical applications.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
280
280
https://ijmp.mums.ac.ir/article_12929_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12929
Brain Activity Map Extraction from Multiple Sclerosis Patients Using Resting-State fMRI Data Based on Amplitude of Low Frequency Fluctuations and Regional Homogeneity Analysis
Meysam
Siyah Mansoory
Department of Biomedical Engineering, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Razie
Chehreh
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Karim
Khoshgard
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: Multiple Sclerosis (MS) is the most common non-traumatic neurological diseases of young adults. MS often reported during ages 20-62. MS affects the various anatomical parts of the central nervous system. Up to 65% of multiple sclerosis patients MS patients suffer from various problems, such as fatigue, depression, pain and sleep disorders. Unlike MRI, that only shows anatomical data of the brain, the fMRI technique can reveal functional relationship and brain activity map. Analysis of fMRI data in patients with MS can provide valuable information on post-traumatic neurological changes, so it leads to understanding the pathophysiology of the disease as well as the better choice of treatments methods. Many studies have been done on patient’s whit MS using fMRI data but unfortunately the results of the studies are not compatible. It means that changes in fMRI data which is done based on the disease are not specified completely.
Materials and Method: Based on a neurologist's diagnosis, resting-state fMRI imaging was done on 20 patients with MS and 20 normal persons. . In order to analyze the data, the Amplitude of Low Frequency Fluctuations (ALFF) and Regional Homogeneity (ReHo) methods were used to study the activity of brain regions. To do that, the time series related to each three-dimensional volume voxels were extracted. After selecting the desired clusters in standard space and registering functional images on structural images and then on standard atlas between two groups, the results were analyzed statistically. All steps of this study were done using the Resting- State fMRI Data Analysis Toolkit in MATLAB software.
Results: By comparing the statistical data of the two groups of testing and controlling, the results of collective analysis of low frequency oscillations in resting state indicated increased activity in motor and cerebellar parts and decreased activity in central parts. Also, the results of the statistical analysis of functional relationships show a significant level of negative correlation in low frequency oscillations between some of the motor regions and basal nuclei, which are observed only in MS subjects, and there is only a significant level of positive correlation within the motor regions or the core nucleus in normal subjects.
Conclusion: MS might be related to reduction activity of thalamus and increase activity of lateral ventricular volume of the brain.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
281
281
https://ijmp.mums.ac.ir/article_12930_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12930
Economic evaluation of radiopharmaceutical Mo-99 production in reactor and accelerators in Iran
Amir Hossein
Mahjoob
MSc student of Nuclear Engineering (Radiotherapy) in Shiraz University
author
text
article
2018
eng
Introduction:
Radioisotope 𝑇𝑐-99m is one of the most important in the field for thyroid imaging, intestinal or bladder appendages, blood vessel imaging, detecting blood clots, bone imaging, etc. This necessary radioisotope is the daughter of a nuclear-radioactive molybdenum-99 that is manufacturing in accelerators or research reactors. Our world now needs 12000 Ci. Given the growing trend in nuclear medicine imaging, the economic issue of producing the radioisotopes required for these images is going to be important. In this paper, using the TALYS code and the software SRIM, TRIM and MATLAB, we compared the accelerator gain with the reactor and provided an optimized method for Iran.
Materials and Methods:
Using the TALYS code, we find the dependence of the cross-sectional energy on energy and then, using the SRIM code, we consider the energy dependence of the protons in depth penetration. Using MATLAB, we obtain the mean value of the cross section using the equations from TALYS, and obtain yield for protons we guess demand Iran’s need.
Results:
So if we have two 30 Mev (and 300µA) accelerators in the two three-day sets in week with a one-day rest having irradiate, then Iran needs about 70-80 Ci will be satisfy, and the rest of the demand for Tehran will be from in direct way of Tc-99m production. In this case, for each accelerator per week, we need about 2 grams per week and for direct production of Tc, 40 mg of enriched molybdenum 100 per day is needed, which costs are calculated.
Conclusion:
Even without considering the cost of electricity and waste disposal and separation, and only by comparing the annual uranium cost with the total accelerator cost, we will find that the accelerator method is much more convenient and reasonable. In the accelerator method, regardless of the initial cost of the devices, we annually had the cost of electricity and enriched molybdenum and other costs that are shared with the reactor (employee salaries and separation, etc.). Perhaps these costs are higher in the reactor. In addition, we have a lot of problems with the acquisition of enriched uranium and we buy it at a great price from Argentina or Russia. Or the cost of molybdenum 99 at an annual price of $ 4 million from Russia, which can be produced at a lower cost at home and, in addition to economic optimization, also leads to entrepreneurship.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
282
282
https://ijmp.mums.ac.ir/article_12931_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12931
Brain Activity Map Extraction of Neuromyelitis Optica Patients Using Resting-State fMRI Data Based on Amplitude of Low Frequency Fluctuations and Regional Homogeneity Analysis
Meysam Siyah
Mansoory
Department of Biomedical Engineering, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Hosna Nouri
Tahneh
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Karim
Khoshgard
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: Neuromyelitis Optica (NMO) is a rare inflammatory disease of the central nervous system which generally affecting the spinal cord and optic nerve. Damage to the optic nerve can result in the patient's dim vision or even blindness, while the spinal cord damage may lead to sensory and motor paralysis and the weakness of the lower limbs in the patient. Magnetic Resonance Imaging (MRI) is one of the imaging methods for NMO detection. Recently, the fMRI scans in NMO disease is very common. fMRI is a non-invasive method which uses magnetic technology. fMRI images are related to environmental changes in the blood flow of any brain regions. This imaging method is designed to identify parts of the brain cortex activated for specific tasks, and it is mostly used to carry out neurological studies.
Materials and Method: After the initial diagnosis by the neurologist, rest-fMRI imaging was performed on 25 healthy persons as the control group and 25 persons suffering from NMO as the test group. after the data were obtained, the data pre-processing was carried out which included the slice-timing, motion correction, and spatial normalization steps. In order to eliminate the noise and other artifact effects, a band-pass filter was used. Finally, the data were filtered using a Gaussian kernel for the smoothing purposes. The amplitude of low frequency fluctuations (ALFF) and regional homogeneity (ReHo) methods were used to investigate the activity of brain regions. For this purpose, at first, time series associated with each of the brain 3D volume voxels were extracted. After the selection of the brain regions between the two groups, registering the functional images on structural images and the standard atlas, the statistical analysis of the results was carried out. The present research was performed in MATLAB using the Resting-State fMRI Data Analysis Toolkit.
Results: The statistical comparison of the images of the test and control groups which was obtained from the group analyses of the low frequency fluctuations mappings in the resting state pointed to a decrease in the activity of the left Anterior Cingulate Cortex, right precuneus, left Posterior Cingulate Cortex, medial frontal gyrus, and right middle temporal gyrus regions. On the other hand, there was observed an increase in the activity of right inferior frontal gyrus and left thalamus regions.
Conclusion: The findings in the data associated with fMRI images in NMO patients, showed an abnormal brain activity in the regions associated with cognitive, optic, and motor tasks. This may be because of the consistency of the brain with functional disorder in NMO subjects as well as the compensation of this pathophysiological disorder by the other parts of the brain.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
283
283
https://ijmp.mums.ac.ir/article_12932_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12932
The effect of exposed to radiofrequencry emitted from jammer on the spatial memory
Abass
Shahee
MSc student of immunology, Tehran University of Medical Sciences, Tehran, Iran
author
Fatemeh
Shahnazar
Medical Student of Fasa University of Medical Sciences, Fasa, Iran
author
Manzar Banoo
Shojaeifard
Physiology Department of Fasa University of Medical Sciences, Fasa, Iran
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction: The Widespread range of mobile phone application in life has induced many problems in the societies. This subject has caused jammer router is used in some places. Jammer router blocks signal transfer from base station to the cell phone. In the other hand, the extensive application of electromagnetic field in all aspect of life has increased fears and worries about side effects on the human healthy indexes, including learning and memory. Memory can be defined as the skill of saving the experiences and remembering the learned processes or events. This study was used Morris Water Maze Technique to test working spatial memory in rats after exposed to radiation emitted jammer.
Materials and Methods: In this study, 50male rats (220-250g) randomly divided 5 groups (n=10): control, sham1&2, Experiment1&2. Experimental groups were irradiated through switched –on mobile phone jammer router2h/day once and other group 2h/day for two weeks’ sequence. This procedure repeated for sham groups but with switched-off jammer router. The distance of animal cages from jammer antenna was 30cm. Learning ability and spatial memory were assessed by Morris Water Maze Technique Sham& Experimental groups were trained 4trails/day during 5 days. Then, data and parameters (latency time, path length) analyzed in different groups for founding the exposure radiation effect from jammer routers on the spatial memory in rats.
Results: The analyzed data did show the recorded mean from latency time to reach the hidden platform also the average of path length traveled to reach platform in one- day irradiated groups, as well as, among exposure groups during two weeks were significantly different relative to control. This means radiation emitted of jammer device have reduced learning level in exposure groups compare to control. However, duration exposure radiation 2h/day once or two weeks’ sequence did not show significant difference on the considering parameters. In the other hand, duration exposure radiation 2h/day once or2h daily for two weeks’ sequence did not show significant relationship on the spatial memory and learning performance.
Conclusion: Exposure to jammer radiation was impaired spatial memory and learning abilities in exposure rats, but duration radiation did not show statistical significant effect on the learning performance and spatial memory.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
284
284
https://ijmp.mums.ac.ir/article_12933_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12933
Quality assurance prusedore in high dose rate bracythrapy
Ali
Rajabi
Secondary Standard Dosimetry Laboratory (SSDL), Pars isotope Co., Karaj, Iran.
author
Mohsen
bakhshandeh
Associate Professor, Radiology Technology Department, Allied Medical Faculty, Shahid Beheshti University of Medical Science,Tehran, Iran
author
Ali
Jabbari arfaei
Tajrish Shohada Hospital, Tehran, Iran.
author
text
article
2018
eng
Introduction: Quality assurance is essential for obtaining the best achievable tumor control, avoiding unnecessary side effects, accuracy and safety during performing High Dose Rate (HDR) Brachytherapy (BT). Quality assurance is extremely important because HDR BT procedures are performed quickly, with high doses given in a short time period, with little opportunity for correction. The quality assurance procedure can be divided into the four categories: Treatment unit, Treatment Planning System (TPS), Imaging and Patient treatment procedure. These categories include different tests which should to be done periodically in order to verify the accurate treatment. In this study a number of important quality assurance tests were performed.
Materials and Methods: Physical and Safety parameters of the Sagi Nova (Eckert & Ziegler Bebig GmbH) machine with Co-60 source was investigated. Determination of source position accuracy was done in two methods 1) video-ruler source position and 2) Gafchromic film with posi check phantom (PTW, Germany). Reference Air Kerma Strength (RAKS) of the source was measured according to IAEA TECDOC-1274 using a well-type ionization chamber (PTW, Germany) with suitable holder for insertion of the afterloader's catheter. Another physical parameter like Length of treatment tubes, Transit time, Timer consistency and Timer linearity were measured. Safety parameters like Communication equipment, Applicator attachment, Catheter attachment lock, Door interlock, warning lights, Room monitor, Hand held monitor, Treatment interrupt, and Emergency stop were evaluated.
Results:
All items related to safety parameters investigated and defects have been resolved. Source positioning accuracy in both video-ruler and Gafchromic measurement showed a difference of less than one millimeter. RAKR measured by the well-type ionization chamber in comparison with the input value in the TPS showed a 0.5% difference which is acceptable.
Conclusion: Quality assurance of Sagi Nova HDR BT machine was performed. Physical and Safety parameters were investigated. The measurements showed acceptable results. Because of the high importance of HDR BT treatment, it is recommended each center perform quality assurance tests according to the existing protocols in the regular time interval.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
285
285
https://ijmp.mums.ac.ir/article_12934_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12934
Epileptic seizure detection based on The Limited Penetrable visibility graph algorithm and graph properties
Zeynab
Mohammadpoory
PHD, Department of Biomedical Engineering, Hakim Sabzevari University, Sabzevar, Iran, Telephone: 051-44012609, Fax: 051-44012605, z.mohammadpoory@gmail.com
author
Javad
Haddadnia
PHD, Department of Biomedical Engineering, Hakim Sabzevari University, Sabzevar, Iran, Telephone: 051-44012609, Fax: 051-44012605, Haddadnia@hsu.ac.ir
author
Mona
Azizi
PHD, Department of Physic, Hakim Sabzevari University, Sabzevar, Iran, Telephone: 051-44012609, Fax: 051-44012605, monaazizi68@gmail.com
author
text
article
2018
eng
Introduction:
Epileptic seizure detection is a key step for both researchers and epilepsy specialists for epilepsy assessment due to the non-stationariness and chaos in the electroencephalogram (EEG) signals. Current research is directed toward the development of an efficient method for epilepsy or seizure detection based the limited penetrable visibility graph (LPVG) algorithm.
Materials and Methods:
Single channel EEG signals are mapped into the LPVGs and then 14 features are calculated from these graphs. Then some features are selected using Sequential forward feature selection method and given to error-correcting output codes (ECOC) to classify signals into three groups of healthy, seizure free (interictal) and during a seizure (ictal) groups.
Results:
Experimental results show our method can classify normal, ictal and interictal groups with a high accuracy of 96.31%.
Conclusion:
The proposed method is fast and easy. Comparison the performance of the proposed method with other automatic seizure detection method also shows our method has better performance.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
286
286
https://ijmp.mums.ac.ir/article_12935_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12935
Investigation of Freedom-Degrees impact on Modulation of Radiation
Tahmine
Hoseinkhani
Department of Medical Engineering and Physics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Ahmad
Mostaar
Department of Medical Engineering and Physics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Amin
Asgharzadeh Alvar
Department of Medical Engineering and Physics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Nowadays tendency to apply more degrees of freedom in high-tech radiotherapy systems, and consequent complex process to optimize dose calculation and delivery algorithms, is a challenge of radiation therapy optimization. Faster MLC speed, dose rate, Gantry angle variation, and other degrees, which have been utilized in IMRT, IMAT, VMAT, improved modulation of intensity radiation that resulted in better quality in treatment plans.
In this study, we modeled a pair of multi leaf collimators(MLC) to investigate ideal dynamical features such as speed and acceleration of MLC mathematically. Then we estimate an equation of MLC's motion in dynamical sliding window algorithm to investigate impact of some factors such as initial position of MLC, speeding up MLC, delivery time and variable dose rate on optimizing dose delivery algorithms.
Materials and Methods: Seven intensity maps extracted from a prostate RT plan. MATLAB environment (R2017a version) was selected to define and solve optimization problem. In one dimension a pair of MLC modeled to reach out a row of intensity matrix diagram. Because of nonconcave nature of problem, gradient descent algorithm utilized and many criteria such as different start and end point of movement of MLC, direction of MLC, time delivery and dose rate subjected to optimization process.
Results: Intensity map, velocity, acceleration, and output errors were plotted. However, the increase in the time can lead to a decrease in the error value - from 91% to an optimum of 2%; the error value did not reduce by increasing over optimum time significantly. Also increasing the speed of MLCs results in a significant reduction in relative error, although the assumption of the ability to reach out the infinite velocity does not lead to a reduction in relative error rate, and the optimization process was stopped.
Conclusion: Although unidirectional movement in sliding window algorithm demonstrates as a suboptimal method, in volumetric methods bidirectional movement could have been optimal. Although that seems to get better outcome by speeding up MLC, it’s not as a rule routinely and infinite speed have been result in stopping optimization prematurely. In higher speed, we don’t see the linear relationship mathematically and over speeding up may lead to more anarchy in MLC movements reality. Not only increasing time delivery dose after a certain limit did not cause to significant decrease in optimization error, but also it may lead to other errors, and trade of between time and quality should be recognized. Variable dose rate can save more photons which sacrificed in modulation with tungsten blocks.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
287
287
https://ijmp.mums.ac.ir/article_12936_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12936
Microdosimetry study of a multicellular model with mono-energetic electrons using Geant4-DNA simulation toolkit
Payvand
Taherparvar
Faculty of Science, University of Guilan, Rasht, Iran, Email: p.taherparvar@guilan.ac.ir, Fax and Tel:+981333323132
author
Ramak
Salim
Faculty of Science, University of Guilan, Rasht, Iran, Email: ramaksalim@yahoo.com, Fax and Tel:+981333323132
author
Amir Abbas
Neek
Faculty of Science, University of Guilan, Rasht, Iran Email: amirabbasneek2022@gmail.com, Fax and Tel:+981333323132
author
text
article
2018
eng
Introduction:
The goal of any type of radiation therapy in the treatment of tumors, in addition to destroying cancer cells, is to minimizing radiation to nearby healthy cells and thus reducing side damages. For this purpose, targeted radiation therapy (TRT) is more effective in treating of single cells or small cluster of cells. The main factor in the success of this method is that the range of charged particles used in treatment does not exceed the cellular dimensions; this justifies the use of electron emitters with the energy as low as possible (especially Auger electrons).
Materials and Methods:
In this study, the Monte Carlo simulation toolkit, Geant4-DNA, has been used due to the accurate computational models used to simulate the transport of charged particle at the cellular scale (micrometer and lower). So, with the help of this code, a multicellular model (cell cluster) consisting of five spherical cells (containing the nucleus) of liquid water, has been simulated in the medium of tissue material. One of the cells is considered as the source, and with the uniform random sampling of 100,000 mono-energetic electrons with an initial energy of 1-20 keV within this cell, energy deposition and the S-value (mean absorbed dose in the target per unit cumulated activity in the source) in each cell is calculated using microdosimetry approach and the proposed formulation of MIRD committee.
Results:
A comparison of the values obtained for the source cell with the corresponding MIRD values indicates a good agreement, which implies the high ability of Geant4-DNA in microdosimetry simulations. The evaluation of the results suggests that a large part of the energy emitted within the source cell is deposited in the cell itself, which is lowered by increasing energy so that for the energy of 20 keV, it reaches less than 50%. Also, the cell that is far from the source cell (compared to other cells) has a lower energy deposition and S-value.
Conclusion:
From the assessment of the calculated values and their comparison with each other, it is understood that the less the energy of the primary electron is, the less energy is delivered to the adjacent healthy cells. Due to the very low threshold excitation of liquid water (7.4 eV) which is the main compartment of the cells, this is meant to reduce the risk of damage to adjacent healthy cells. Of course, the electron energy should not be so low that reduces its fatality for cancer cells and thus the efficacy of treatment. Therefore, attention to the mentioned cases, as well as the dimensions of the cell studied and its distance with adjacent cells, is crucial for the selection of an efficient electron-emitter radionuclide.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
288
288
https://ijmp.mums.ac.ir/article_12937_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12937
Evaluation of Organ Specific peripheral dose for Gamma knife 4C based on Monte Carlo
Mahdie
Behjati
Nuclear engineering unit, Department of Energy Engineering, Sharif University of Technology, Tehran, Iran.
author
Seyed
Pezhman Shirmardi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran.
author
text
article
2018
eng
Introduction:
Stereotactic Gamma Knife radiosurgery has been widely used for treating brain tumors. The scattered radiation outside of treatment field (peripheral dose) can induce the secondary cancer to specific organ.
This paper investigated the absorbed dose to eyes, thyroid, heart, lung, breast and colon using a Monte Carlo technique for Mird phantom. We also study the effect of depth of tumor and helmet size on the peripheral dose.
Materials and Methods:
In this work, gamma knife 4C was simulated as 201 surfaces disc source modelling. Based on this model, parallel beams of uniformly distributed method emitted form 201 disk sources that correspond to inner aperture for helmet. The photon beams converged at the isocenter of gamma knife. The coordinates of centers of these discs as planes to be determined using Matlab software.
The 201 disc sources simulated for 4, 8, 14 and 18 mm helmet and also various tumor depth using mcnpx.
Results:
Large differences were observed between the organs close to target volume such as eyes and thyroid respect to organ far from target volume. The eyes received the maximum dose and the left eye dose was more than right one. Significant differences weren’t observed for organ peripheral dose with increase helmet size.
The peripheral organ doses were increased with decrease of isocenter point as result of decrease depth of tumor due to decrease scattered radiation.
Conclusion:
Treatment planning should be considered gamma knife peripheral peripheral doses for organs near to target volume specially in surface tumor.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
289
289
https://ijmp.mums.ac.ir/article_12938_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12938
A quantitative investigation on lung tumor site on its motion tracking in radiotherapy with external surrogates
Ahmad
Esmaili Torshabi
Medical Radiation Division, Faculty of New Sciences and Technologies, Graduate University of Advanced Technology, Haftbagh St. Kerman, Iran
author
Seyyed Amirreza
Dastyar
Medical Radiation Division, Faculty of New Sciences and Technologies, Graduate University of Advanced Technology, Haftbagh St. Kerman, Iran
author
text
article
2018
eng
Introduction: In external beam radiotherapy each effort is done to deliver 3D dose distribution onto the tumor volume uniformly, while minimizing the dose to healthy organs at the same time. Radiation treatment of tumors located at thorax region such as lung and liver has a challenging issue during target localization since these tumors move mainly due to respiration. There are several methods to compensate the effect or tumor motion error, clinically. Recently, stereotactic body radiation therapy strategy has been proposed clinically that can lead to better local control using external surrogates. In this method, the exact information of tumor position in real-time is obtained using consistent correlation models between tumor motion and external surrogates motion. In this work, the influence of motion variability and the site of lung tumor has been taken into account over total treatment time.
Materials and Methods: In this study, motion information of lung tumor of real patients treated with the CyberKnife Synchrony system, have been utilized. Real time tumor motion tracking is performed by developing a fuzzy logic based correlation model to predict tumor position using external surrogate’s motion. In this work the variabilities of lung tumor motion in the Superior-Inferior (SI), Latero-Lateral (LL), and Anterior-Posterior (AP) directions and their geometrical location in lung region have been investigated on the performance accuracy of correlation model, as metric. With divided lung tumors location into four upper, lower, left and right sites.
Results: Targeting errors between of 20 patients with lung tumors located at various sites have been recorded using Root Mean Square Error (RMSE). Intra-fraction variation of lung tumors ranges from 4.0 to 70.5 mm at SI, 1.7 to 75.5 mm at LL, 1.8 to 40.7 mm at AP directions. Total treatment time ranges between 27.0 to 118.8 minutes over total patients. Moreover, the average of RMSEs during tumor tracking by means of correlation model are
15.6 mm, 6.7 mm, 7.8 mm and 9.5 mm for upper, lower, left and right tumors, respectively in one division.
Conclusion:
There are many influencing factors and patterns on lung tumor motion management at external radiotherapy. By understanding these factors and considering to them during real time tumor tracking, the treatment quality may have enhanced significantly at stereotactic body radiation therapy. In this work we assess tumors motion variability and their geometrical sites on the accuracy of our developed fuzzy correlation model, quantitatively.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
290
290
https://ijmp.mums.ac.ir/article_12939_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12939
Commissioning and early experience with a new generation low-energy linear accelerator in zahedan
Masoumeh
Farsizaban
Department of medicine, zahedan university of medical sciences, zahedan, IR Iran. NO: 09151405378 e-mail address: Ma_farsizaban@yahoo.com
author
Vida
Sargazi
Ms medical physic, department of para medicine, Zahedan University of Medical Sciences, Zahedan, I.R. Iran.
author
Mahsa
Poorjangi
Medical students research commitee , Zahedan University of Medical Sciences , Zahedan, I.R.Iran .NO:09156094283 e-mail address: Mahsapoorjangi@yahoo.com
author
text
article
2018
eng
Introduction:
Since commissioning beam data are treated as a reference and ultimately used by treatment planning systems, it is vitally important that the collected data are of the highest quality to avoid dosimetric and patient treatment errors that may subsequently lead to a poor radiation outcome. Beam data commissioning should be performed with appropriate knowledge and proper tools and should be independent of the person collecting the data. low-energy linear accelerator was introduced in the clinical area by ELEKTA Medical Systems.
This machine was first installed in Sistan and Baluchestan state in 2016.
The aim of the present contribution was to report experience about its commissioning and first year results from clinical operation.
Materials and Methods:
In this research, we used water phantom model DoseviewTM 3D version1.2 and A19 and A28 ion chambers. Commissioning data, beam characteristics and the modeling into the treatment planning system were summarized.
. Finally, since the system is capable of delivering Threaetment dose with 6 Mev of energy , a summary of the tests performed for such modality to assess itsperformance in preclinicalsettings and during clinical usage was included.
Results:
The absorbed dose according to the TRS398 protocol in the absolute dosimetry was D = 0.010042Gy / Mu.
In a relative dosimetry, PDD was calculated at different depths and fields, results at 10 cm depth for field 10 × 10 was equal to 0.661 and for the field 30 × 30 at the same depth of 10 cm was equal to 0.690. Also Measurements were made to determine the flatness and symmetry in different fields at a depth of 10cm. For example, the flatness in field 10×10 at depth of 10cm was 3.7 and its Asymmetry value was -0.7%.
Conclusion:
The results of the commissioning tests and of the first period of clinical operation, resulted meeting specifications and having good margins respect to tolerances. Linac was put into operation for all deliverytechniques; in particular, as shown by the pre-treatment quality assurance results, it enabledaccurate and safedelivery of 3D planning.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
291
291
https://ijmp.mums.ac.ir/article_12940_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12940
Study of radio protective effect of Thymus vulgaris essential oil against ionizing radiation on peripheral blood mononuclear cells (PBMCs)
Pegah
Sanati
MSc Student, Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Ali
Shams
Associate Professor, Department of Immunology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
BiBi Fatemeh
Haghirsadat
Assistant Professor, Department of Nanotechnology, Faculty of Paramedicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Masoud
Shabani
Assistant Professor, Department of Radiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Nima
Hamzian
Assistant Professor, Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
text
article
2018
eng
Introduction:
Today ionizing radiation (IR) plays an important role in medicine, both in diagnostic and therapeutic field. Doctors, medical staff and patients are all in danger of side effects of IR so there is a need to protect them against deleterious effects of ionizing radiation. Thymus vulgaris has biological activities like antioxidant and antibacterial activity. Aim of this study is to determine the radio protection effect of essential oil of Thymus vulgaris on peripheral blood mononuclear cells (PBMCs).
Materials and Methods:
At the first step essential oil was obtained from Thymus vulgaris dried powder. Peripheral blood samples were collected from four volunteer donors. PBMCs were treated with non-toxic concentration of Thymus vulgaris essential oil in two groups of 24 hours before and 1 hour after exposure to both doses of 0.25 and 2 Gy of ionizing radiation. After 72 hours viability percentage was determined by MTT assay.
Results:
Non-toxic concentration was obtained in 130 µg/ml. viability percentage in groups non- treated, treated 24 hours before and treated 1 hour after exposer to 0.25 Gy of ionizing radiation was 65%, 85% and 55% respectively. Also, viability percentage for the same groups that were exposed to 2 Gy of ionizing radiation was 75%, 105% and 65% respectively.
Conclusion:
As results demonstrate, it is an obvious radiation protection effect in groups that were treated with Thymus vulgaris 24 hours before exposure to ionizing radiation and also it is more specify in higher dose of radiation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
292
292
https://ijmp.mums.ac.ir/article_12941_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12941
Quality enhancement of Pelvis electronic portal images in order to improve treatment accuracy
Hanie
Ghaempanah
Department of Biomedical Engineering and Medical Physics Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mohammad Reza
Deevband
Department of Biomedical Engineering and Medical Physics Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Amin
Asgharzadeh Alvar
Department of Biomedical Engineering and Medical Physics Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mohsen
Najafi
Shohadaye haftome_tir hospital, Oncology department, Tehran, Iran
author
text
article
2018
eng
Introduction: In order to reduce patient setup error in treatment field, portal images with treatment beam (megavoltage x-ray) are widely used. These images are acquired by electronic portal imaging devices (EPID). However, portal images suffer from insufficient anatomical information, contrast, and spatial resolution, because of the fact that Compton scatter is the main photon interaction in megavoltage range. The aim of this study is to inspect the efficacy of multiresolution processing method on enhancing quality of these images, which improves the accuracy of the setup verification.
Materials and Methods: images of pelvis area were captured which had a low level of quality. Therefore, three major steps are required: contrast enhancement, noise reduction and edge sharpening. A multiresolution processing which can decompose and combine the different scales information are proposed to overcome deficiency of histogram-based enhancement methods. EPID images were decomposed to details and approximation components in order to observe structures in different scales. As a result, the components with highest level of noise and them with bone structure information can be identified. The components can be weighted for reducing the noise and sharpening the edges. Finally modified components are used to reconstruct the enhanced images. Anatomical landmarks in processed images were scored visually by observers in three different levels (physician, physicist and technologist) to qualify the efficacy of the algorithm.
Results: The pelvis anatomical landmarks (sacrum, crest of ilium, symphysis, ischium, pubis, acetabulum, sacroiliac joint) were compared by many experts as a quantitative evaluation in terms of their quality, showing the superiority of the processed images. This improvement was reported by all of the experts in different levels, which was mentioned above.
Conclusion: it was seen that noise and anatomical structures are separable in different components. The results show that the proposed method in this study significantly improved the quality of portal images, which leads to much more accurate organ localization during radiotherapy of pelvis area.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
293
293
https://ijmp.mums.ac.ir/article_12942_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12942
Investigating antimicrobial effect of Zataria extracts produced by ultrasound on salmonella typhimurium
Masoumeh
Farsizaban
Department of medicine, zahedan university of medical sciences, zahedan, IR Iran. NO: 09151405378 e-mail address: Ma_farsizaban@yahoo.com
author
Mahsa
Poorjangi
Medical students research commitee , Zahedan University of Medical Sciences , Zahedan, I.R.Iran .NO:09156094283 e-mail address: Mahsapoorjangi@yahoo.com
author
text
article
2018
eng
Introduction:
Zataria multiflora is a plant of the Lamias family. The most effective antimicrobial composition is its thymol and carvacrol. Salmonella typhimurium is a genus of Salmonella from the Enterobacteriaceae family. This gram-negative basil, optional aerobic or anaerobic, cause diseases such as inflammation of the intestine, systemic infection, and intestinal fever. The purpose of this study is to investigate antimicrobial effect of Zataria extracts produced by ultrasound on salmonella typhimurium bacteria.
Materials and Methods:
Salmonella typhimurium was isolated from fecal specimens of poultry in 1394. The Carla plant is placed in an ethanol solvent after collecting and milling and then exposed to ultrasound for 1 hour. Minimum inhibitory concentration and minimum bactericidal concentration are determined by microdilution method.
Results:
The results of this study showed that the Zataria extract showed the most inhibitory effect in the concentration of 0.62 mg / ml and the highest inhibitory concentration was 1.25 mg / ml. The highest bactericidal concentration was 25 mg / ml. Salmonella typhimurium strains have been resistant to ampicillin antibiotics.
Conclusion:
It would be possible to treat Salmonella typhimurium infection by developing an appropriate herbal medicine with less side effect. However, ultrasound has increased the antimicrobial activity of the extract of the plant in this study.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
294
294
https://ijmp.mums.ac.ir/article_12943_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12943
Dosimetric Parameters Estimation of I-125 Brachytherapy Source in fat phantom using GATE8.0 code
ayvand
Taherparvar
Faculty of Science, University of Guilan, Rasht, Guilan, Email: p.taherparvar@guilan.ac.ir, Tell and Fax numbers: 01333323132
author
Zaynab
Fardi
Faculty of Science, University of Guilan, Rasht, Guilan, Email: foroozan93fardi@gmail.com, Tell and Fax numbers: 01333323132
author
text
article
2018
eng
Introduction:
Brachytherapy is one type of internal radiation therapy where radiation sources, which are usually encapsulated, are placed as close as possible to the tumor site or inside the patient's body. In this technique, it is important to determine dose distribution around the brachytherapy capsule to create optimal treatment plant. In this way, dosimetric parameters are estimated according to TG-43U1 protocol in the water phantom as reference medium while the attenuation coefficient of the sources in the water phantom is different from that of different tissues. The purpose of this study is to investigate the effects of the fat phantom materials on the TG-43U1 dosimetery parameters of the I-125 brachytherapy source using GATE 8.0 Monte Carlo code.
Materials and Methods:
In this work, we used GATE_v8.0 (Geant4 Application for Emission Tomography) to calculate of dosimetric parameters of the I-125 brachytherapy source model 2301. At first, validation of the GATE platform was performed by some criteria such as dose rate constant, radial dose function, 2D anisotropy function inside liquid water according to the AAPM TG-43. Then, the Monte Carlo simulated dosimetric parameters of the 2301 I-125 were calculated in fat phantom. The TG-43 dosimetry parameters of the brachytherapy source were compared with those of the fat phantom.
Results:
Dosimetric parameters of simulated I-125 brachytherapy capsule show good consistency compared with the other study of the Monte Carlo simulation of I-125 source. The maximum deviation was about 9%. The maximum relative deviation of radial dose function of the fat tissue compared with water medium were about 13% at distances below 1cm. These differences increased, when the distance from the source increased. At the distance of 5cm from the source, it approximately reached to 55.67%. The maximum relative deviation of the anisotropy parameter of the fat phantom was observed about 6.7% compared with the water phantom.
Conclusion:
There was a good agreement between the results of this work and other study in calculation of dosimetric parameters of brachytherapy I-125 (model 2301) brachytherapy base on the recommendations of TG-43U1 protocole, using GATE Monte Carlo simulation method. Acquired results show that the obtained data can be used to develop GATE code for treatment plan of brachytherapy I- 125 brachytherapy source. Furthermore, In the clinical application of the I-125 brachytherapy source, which is contracted in the treatment of the adjacent tumors to the fat tissues, the correction factors of the fat tissues must be applied after dosimetric parameters calculation in water phantoms in the treatment planning to estimate accurate results for brachytherapy treatment planning.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
295
295
https://ijmp.mums.ac.ir/article_12944_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12944
A study on the esophageal cancer radiotherapy effects on the patient’s lung health
Maryam
Ghorbanipoor
M.S. student of Medical Physics, Immunology research center, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. E-mail: a.ghorbanipoor@gmail.com
author
Parinaz
Mehnati
Associate Professor of Medical Physics (Ph.D.), Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Asghar
Mesbahi
Professor of Medical Physics (Ph.D.), Medical Radiation Sciences Research Team, Tabriz University of Medical Sciences, Tabriz, Iran
author
Behnam
Nasiri Motlagh
Radiation oncologist (MD), Department of Radiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Mohammad
Mohammadzadeh
Radiation oncologist (MD), Department of Radiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
author
text
article
2018
eng
Introduction:
Radiotherapy with or without surgery plays an important role in the treatment of patients with esophageal cancer. In the treatment planning of esophageal cancer, usually normal lung volume was observed in the treatment fields and probably received high radiation dose. The incidence of radiation pneumonitis (RP) after radiotherapy (RT) for sensitive organ of lung is predictable. In this study some clinical and dose-volume factors were presented to identify patients at risk of radiation pneumonitis.
Materials and Methods:
Patients with esophageal cancer who candidate for radiotherapy were tested for symptoms of lung disease including cough, chest pain, fever before and after radiotherapy by physician. Patient properties and history included age, sex, surgery and smoking history were recorded. Dose-volumetric parameters such as lung volume, mean lung dose (MLD), and lung percent that receiving dose of 5-50Gy (V5-V50) extracted from dose-volume histogram.
Results:
Seventeen women and thirteen men with median age of 63.3 and 69 years studied. The incidence of radiation pneumonitis was 16.7 % in patients who received pre-operative RT with total dose of 50.4 Gy (28 fractions). The results showed that age (<65 or ≥65) and V35 (<14 or ≥14 %) significantly associated with RP incidence in patients treated with pre- operative radiotherapy. Patient properties did not show clear positive or negative correlation with radiation pneumonitis
Conclusion:
Whereas patients with esophageal cancer who received radiotherapy usually did not follow up for radiation pneumonitis, this study suggests that limit the dose-volume parameters to threshold values can be beneficial to reduce the risk of radiation pneumonitis.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
296
296
https://ijmp.mums.ac.ir/article_12945_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12945
cardiac damage in left breast cancer patients
Arass
Rasaei
Young Researchers and Elite club, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Zahra
Mansouri
Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction :Today there is general awareness of the potential damage to the heart in left- sided (more than in rightsided) breast cancer radiotherapy.
Material & Method: Historical changes in tumor and heart doses are presented here along with the impact of different RT techniques and volumes.
Results: Individual and pharmacological risk factors are also examined with respect to radiation damage. The biological mechanisms of harm are only partially understood, such as the radiobiology of heart damage due to the presence of various radiosensitive structures
and their topographic heterogeneity.
Conclusions: individual variability may expose patients to higher or lower risks of late
cardiac damage or death. Damage mechanisms and radiobiological characteristics in heart
irradiation are presented in relation to dosimetric and biological parameters.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
297
297
https://ijmp.mums.ac.ir/article_12946_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12946
Evaluation of Testis functioning during Pelvic Radiotherin the presence of testis lead shield
Marjaneh
Mir-Sadraee
Department of Radiation Oncology, Reza Radiotherapy and Oncology Centre, Mashhad, Iran.
author
Azadeh
Soleimani
Department of Medical Physics, Reza Radiotherapy and Oncology Centre, Mashhad, Iran.
author
Mohammad
Mohammadi
Department of Medical Physics, Reza Radiotherapy and Oncology Centre, Mashhad, Iran.
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, Australia
School of Physical Sciences, The University of Adelaide, Adelaide, Australia
author
Mohammad Taghi
Batiar
Faculty of Nuclear Sciences, Shahid Beheshti University, Tehran, Iran
author
Elyas
Sanaei
Department of Radiation Therapy Technology, Reza Radiotherapy and Oncology Centre, Mashhad, Iran.
author
text
article
2018
eng
Introduction: Rectal and bladder cancer are the most common disease among young man. Although External Radiotherapy (EBRT) is one of the most effective treatment options introduced so far, the testis undesired radiation dose increases the risk of infertility and hormonal malfunctioning. The testicles are usually outside of the radiation field, but they can be exposed either to scattered and or direct radiation pending on the distance of radiation field, patient thickness and radiation beam energy.
To evaluate testis functioning, the LH, FSH and testosterone levels in rectal and bladder carcinoma and effect of testicular shielding in sex hormonal level during external beam radiotherapy were evaluated. In order to control neutron dose received to the region of interest, shield optimization through Geant4 simulation toolkit was also investigated.
Materials and Methods: Thirty patients with bladder and rectal adenocarcinoma received pelvic radiotherapy. All patients received 5040-Gy radiation dose ,1.8Gy/fraction and five days per week. 15 patients were treated without testicular shielding and others received radiotherapy with testicular shielding made of 1.5 centimeter lead. Blood tests were performed before and after radiotherapy for both group. The head of Simens Primus were simulated using Geant4 code. For verification of the simulated linac’s head, the percentage depth doses (PDDs) and Profiles were compared with the corresponding measurements. CT- Structure And Plan Dicom files were then imported to the code and the testicular shield was modelled.
Results:
Based on the Gamma Index results in the first step and evaluation of optimized shielding, testis dose is minimum.
Conclusion:
Although the application of routine shield apparently reduces the radiation dose, the neutron dose should also be taken into account. The modified shield including low atomic number materials reduces the radiation dose and improving hormonal functioning.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
298
298
https://ijmp.mums.ac.ir/article_12947_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12947
The role of relative cerebral blood volume obtained from Perfusion Weighted Imaging-MRI in glioma tumor grading before surgery
Fariba
Allahmoradi
MSc of Medical Physics, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Farhad
Naleini
Assistant Professor, Department of Radiology, Imam Reza Hospital, Kermanshah University of Medical Science, Kermanshah, Iran.
author
Abbas
Haghparast
Associate Professor, Medical Physics Department, Medicine School, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Mehdi
Mohammadi
MSc Student of Medical Physics, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: Glioma is the most common type of brain malignancy among adults. Treatment for this type of tumor involves surgery, radiotherapy, and in higher grades, including chemotherapy. The precise grading of the tumor is critical for treatment planning and prognosis determining. Considering the possibility of problems such as errors in tissue sampling during surgery, as well as errors in histopathological grading of the lesions or the impossibility of surgery and sampling in some patients, the importance of advanced neuroimaging techniques as a non-invasive technique is more pronounced. Perfusion Weighted Imaging (PWI) is one of the advanced MR imaging techniques that can be helpful in tumor grading by evaluating tissue physiology alongside conventional MR images. Relative cerebral blood volume (rCBV) is one of the parameters that is obtained from the analysis of perfusion images. Our purpose in this study is to examine this parameter in tumor grading.
Materials and Methods: 15 primary glioma patients who had confirmed histopathology
entered the study. All patients were initially subjected to conventional MRI and PWI. The
images were reviewed in collaboration with an experienced radiologist and then examined
for determining the threshold values for tumor grading. Results were compared with
histopathologic grade. Statistical analysis was performed using SPSS software.
Results: According to the results of images and statistical analysis, the rCBV threshold value, sensitivity and specificity in the high grade glioma determination were 2.91, 94.6 and 93.7, respectively. There was also a significant difference between high and low grade glioma in rCBV value (P< 0.001).
Conclusion: The advanced PWI-MRI imaging technique increases the accuracy of the glioma tumor marker and also the rCBV value can be recognized as a biomarker for tumor grading.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
299
299
https://ijmp.mums.ac.ir/article_12948_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12948
Evaluation of incidence of intestinal complications during radiation therapy in two supine and prone positions in patients with rectal cancer
Soheila
Yazdani
MSc of Medical Physics, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Mehran
Yarahmdi
Assistant Professor, Department of Medical physics, Kurdistan University of Medical Sciences, Sanandaj, Iran,
author
Manoochehr
Ahmadi
Radiation Oncology Specialist, Tohid Hospital, Radiotherapy Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Behzad
Ghasmi
Radiology Specialist, Tohid Hospital, Radiotherapy Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Zeinab
Salehi
Radiation Oncology Specialist, Tohid Hospital, Radiotherapy Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
text
article
2018
eng
Introduction:
Radiation therapy is one of the main treatments for rectal cancer. In three-dimensional conformal radiotherapy, exposure of healthy tissue around the tumor is unavoidable. The small intestine is the most important organ at risk of rectal cancer radiotherapy. Intestinal complications are a major factor limiting the dose radiotherapy for rectal cancer. The most common complication of exposure to the small intestine is diarrhea which can lead to stopping patient treatment. In radiation therapy for rectal cancer, there is no standard position and the supine and prone positions, according to doctors from both will be used. In this study, we investigated the incidence and severity of diarrhea as the most common complication of small intestinal in rectal cancer radiotherapy in two supine and prone positions.
Materials and Methods:
In this study, 10 patients with rectal cancer with an average age of 57 years (range 50-65 years) in two groups with different positions, were followed weekly during treatment. Grade diarrhea was evaluated by a questionnaire based on CTCAE criteria. statistical analysis was performed with the SPSS software.
Results:
At least until the end of treatment all patients experienced grade 1 diarrhea. In the fourth week of treatment, the incidence and severity of diarrhea in both groups reached the highest levels. The results in this week was as follows: in the prone position, grade I and grade II was 40% and 60% respectively; in the supine position, grade I, grade II and grade III was 40%, 40% and 20% respectively. The mean diarrhea grade that observed at the end of each week in the prone position was lower than in the supine position, but this difference was not significant (p>0.05).
Conclusion:
Overall, there is no significant difference between the two supine and prone positions, but the use of prone position seems to reduce the severity of diarrhea in patients and can lead to improved quality of life for these patients.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
300
300
https://ijmp.mums.ac.ir/article_12949_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12949
Role of Apparent diffusion coefficient value in Diffusion Weighted imaging of MRI to assessment of radiotherapy efficiency in the patient with glioma tumor during treatment
Fariba
Allahmoradi
MSc of Medical Physics, Department of Medial physics, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Abbas
Haghparast
Associate Professor, Medical Physics Department, Medicine School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Seyed Salman
Zakariaee
PhD in Medical Physics, Department of Medical Physics and Biomedical Engineering, faculty of medicine, Kurdistan University of Medical Sciences, sanandaj, Iran.
author
Farhad
Naleini
Assistant Professor, Department of Radiology, Imam Reza Hospital, Kermanshah University of Medical Science, Kermanshah, Iran.
author
text
article
2018
eng
Introduction:
Glioma is the most common primary malignancy of cerebral neoplasms in adults, which in spite of therapeutic significant efforts, has a very poor prognosis. The current standard treatment of these patients generally includes surgery and radiotherapy or concurrent chemoradiotherapy with 6 courses of adjuvant use of temozolomide tabs. During these years, the nervous imaging has been valuable for glioma management, which is used to diagnose and characterize tumors, as well as to design neurosurgery and radiotherapy and to achieve treatment efficacy. Among the MR imaging techniques, Diffusion Weighted Imaging (DWI) can be used to assessment of treatment response in glioma tumors.
Materials and Methods:
In this study, 10 patients were selected with primary glioma tumor histopathology, who had the inclusion criteria. The patients were subjected to DWI imaging in three times during treatment until the end of the treatment, the data were analyzed and the mean ADC ratio Value from DWI Images were extracted.
Results: The Patients were divided into two independent groups including patients undergoing chemotherapy and radiotherapy, and patients undergoing radiotherapy. In both groups, data normality was proved (P<0.05), a significant difference was obtained between each stage of pre- with post-treatment stage. According to the observed results, in addition to observing of significant relationship between each of the parameters post- and pre- treatment, the mean ADC ratio was significantly increased in both treatment groups.
Conclusion: Considering the significant of the mean ADC ratio from the DWI images in post- treatment compared to the pre-treatment, these parameters may be used as biomarkers for the treatment response beside of conventional MRI images.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
301
301
https://ijmp.mums.ac.ir/article_12950_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12950
Respiratory motion effect on tumor and normal tissue doses in patients with lung cancer, treated with Intensity Modulation Radiation Therapy and Three Dimensional Conformal Radiation Therapy.
Saeideh
Sadeghi
Msc Student of Medical Radiation Engineering. Islamic Azad University, Science and Research Branch. Tehran, Iran.
author
Seied rabi
Mahdavi
Associate Professor of Medical physics. Medical physics Dept. Iran University of Medical Sciences. Tehran, Iran.
author
Elham
Saeedzadeh
Assistant Professor of Medical Radiation Engineering. Islamic Azad University, Science and Research Branch. Tehran, Iran.
author
Soraya
Salmanian
Assistant Professor of Radiation Oncology. Radiation Oncology Dept, Faulty of Medicine, Iran University of Medical Sciences. Tehran, Iran.
author
Golbarg
Esmaili
Ph.D. of medical physics. Pars Hospital radiotherapy center. Tehran, Iran.
author
text
article
2018
eng
Introduction:
The aim of this study is to investigate the effect of respiratory motion during radiation therapy in patient with lung cancer and comparison of dosimetric parameters between Intensity modulation radiation therapy and three-dimensional conformal radiotherapy in lung cancer.
Materials and Methods:
Two CT scan was performred for each patient. Once in inspiration and once in Expiration mode and the images fused together. GTV and CTV were contoured in two modes. The CTVs combined and by increasing the 10 millimetres margin, the PTV was made. An IMRT plan and a 3DCRT plan for each patient were performed. The plans comparison was based on dose- volume histogram. Organ at risk sparing, HI, CI were analysed.
Results:
V20 of Lung (P=0.043) were lower in IMRT than the 3DCRT plans. The maximum dose of spinal cord (P=0.043) were lower in 3D-CRT than IMRT plans. HI (P=NS) and CI(P=NS) had no significant difference in 3D-CRT and IMRT plans.
Conclusion:
The IMRT technique, in addition to optimizing the dose distribution, reduces lung doses and prevents the occurrence of radiation pneumonia. Also, the method used in this study can be a substitute for 4DCT in treatment centers that are not equipped with this technique.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
302
302
https://ijmp.mums.ac.ir/article_12951_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12951
Gold nanoparticles as a radio-sensitizer of colon cancer cells at high megavoltage energies: An In-Vitro study
Mansour
Zabihzadeh
Nanotechnology Research Center, Faculty of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Clinical Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Ali
Teimoori
Assistant Professor, Department of Virology, School of Medicine, Hamedan University of Medical Sciences, Hamedan, Iran.
author
Vahid
Bayati
Associate Professor, Department of Anatomical Sciences, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Zahra
Ramezani
Associate Professor, Department of Medicinal Chemistry, Faculty of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mojtaba
Hoseini- Ghahfarokhi
Department of Radiology and Nuclear Medicine, School of Para Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: In the point of physical view, there are no significant differences between tumor and normal tissues during radiation therapy. Radio-sensitizers have a key role to address the issue. Exploiting high atomic number, gold nanoparticles (GNPs) have been introduced as novel radio-sensitizers and have shown promising result in the field. Owing to high mass attenuation coefficient of gold at kV energies compared to soft tissue, many studies have been done at the energy range. But for deep located tumors like colon, it is necessary to utilize high energy photons to spare surrounding normal tissues. Therefore, the aim of this work was to investigate the effect of GNPs on radio-sensitivity of a colon cancer cell line (HT-
29) at 18 MV energy.
Materials and Methods: The GNPs were synthesized by seeding-growth method. To determine the morphology and size distribution of the synthesized GNPs, transmission electron microscopy (TEM) was used. The cytotoxicity of GNPs on HT-29 cells was assessed by MTT method in various concentration of GNPs. Moreover, the uptake extent of the nanoparticles into the cells was measured by graphite furnace atomic absorption spectroscopy (GF-AAS). After treatment of the cell with GNPs, they were irradiated by 18 MV photons and colony formation assay was done to calculate sensitization enhancement ratio (SER).
Results: The mean size of synthesized GNPs was 24.75 nm and standard deviation 3.6 nm. TEM images showed spherical like shape for the GNPs. The cytotoxicity of GNPs on Ht-29 cells showed a time-dependent manner so that it was lower for incubation time 48 h than 24
h. Additionally, by increase in GNPs concentration the viability rate of the cells was reduced. The uptake results also exhibited a time dependent pattern and it reached to the maximum after 12 h of incubation time. The colony survival test revealed that the differences between only irradiated and GNPs + irradiated groups was significant for 4, 6 and 8 Gy doses (P<0.05). For HT-29 cells at 18 MV energy, the SER was calculated as 1.25.
Conclusion: It seems the GNPs have great potential to use as radio-sensitizer for colon cancer cells at high megavoltage energies. However, it is recommended to study the effect on animal models.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
303
303
https://ijmp.mums.ac.ir/article_12958_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12958
Investigation of neutron flux by thermoluminescence dosimeters in the neutron-gamma mixed field
Alireza
Sadremomtaz
Department of physics, University of Guilan, Rasht. Iran. sadremomtaz@yahoo.co.uk
author
Peyvand
Taherparvar
Department of physics, University of Guilan, Rasht. Iran. p.taherparvar@gmail.com
author
Sepideh
Gholami
Faculty of Science, University of Guilan. Iran. Gholamisepideh6@gmail.com
author
text
article
2018
eng
Introduction:
Neutrons have many applications in various fields, such as medicine. The important application of neutron in medical science is in Boron Neutron Capture Therapy (BNCT). Because of this, determination of neutron dose and flux is critical for the health maintaining of workers and patients exposed to this beam. The neutron radioisotope sources produce gamma rays in addition to the neutrons, and the neutron fields around these sources are mixed-field neutron-gamma fields. Since the separation of the dose of each radiation component in the compound field is difficult, the gamma-neutron mixed field dosimetry is a major challenge. International Commission on Radiation and Units (ICRU) recommends the use of a dosimeter pair for mixed-field dosimetry that have different responses to each component of radiation. One of the effective methods of neutron dosimetry is the use of the TLD-600/700 dosimeter pair. TLD-600 is 6Li enriched and TLD-700 is 7Li enriched. These dosimeters have the same sensitivity to gamma radiations but TLD-600 is sensitive to thermal neutrons because of high capture cross-section of 6Li, while in low fluxes, TLD-700 has no sensitivity to thermal neutrons.
Materials and Methods:
In this paper, in order to measure the neutron flux of the Ra-Be source in the core laboratory of the Faculty of Science of the University of Guilan. Six TLD-600/700 dosimeters were used in three intervals of 7, 14 and 20 cm from the source
Results:
After 24 hours of irradiation, the intensity of the thermoluminescence of TLDs was measured by TLD reader. Finally, by calculating the calibration coefficient, the measured flux values by the TLDs were determined and compared with the calculated fluxes
Conclusion:
Results show that the measured and calculated values are in good agreement.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
304
304
https://ijmp.mums.ac.ir/article_12959_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12959
The importance of the optimal volume in the treatment of locally recurrent nasopharyngeal carcinoma; brachytherapy or stereotactic radiotherapy?
Nushin
Amini
Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
text
article
2018
eng
Introduction:
Nasopharyngeal carcinoma (NPC) is commonly known as a radiosensitive tumor with the initial good response to radiation.
Despite the improved outcome in loco regional control by the introduction of combining treatment, modern radiotherapy techniques and enhanced imaging studies, local recurrent after primary treatment with rate ranges from 15-58% in 5 years, still remains one of the major causes of failure for patients with NPC.
Re irradiation with various treatment modalities have been reported as a salvage option of NPC recurrent. Considering Limitation of critical organ tolerance doses because of the initial radiotherapy, brachytherapy (BT) and Stereotactic radiotherapy (SRT) irradiation have been encouraging especially if the recurrent lesion is small. The techniques can deliver a highly precise dose to the tumor while minimizing radiation to the surrounding normal tissue. Incidence of severe acute and late complications in these, depending to dose per fraction, total dose, time interval from previous radiotherapy and CTV is different. We compared optimal volume and toxicity in patients with locally recurrent nasopharyngeal carcinoma treated with BT and SRT.
Materials and Methods:
We retrospectively reviewed treatment plan of 12 patients with locally recurrent NPC were treated with BT between 1394 and 1397. However, the technique is applicable only to a small volume tumor, may produce some severe complications, such as soft palate perforation, sphenoid base fistula. But BT were well tolerated with no severe acute complications in this study. Median Tumor volume was 63 cc. The results of studies conducted with SRT despite the high probability of acute complications, Local control was better.
Results:
Improved local control and reduction of complications in both methods was reported to be significant respect to other ways. But the results of Similar study SRT showed that with more fractionated dese, late complications can be reduced. Tumor volume Range of 10.3–56.2 ml in early stage recurrent had Acceptable response rate to treatment. Common Late toxicities in SRT included cranial nerve injury, massive nasopharyngeal hemorrhage, and temporal lobe necrosis. The results of this study showed that with delivery proper dose of each session and the total time in SRT, can decrease Possible late complications.
Conclusion:
It was concluded that the best outcomes with re irradiation related on limited volume recurrence. According to the results of similar experience, SRT is superior to brachytherapy both in terms of providing sufficient dose for para nasopharyngeal spread and local control. SRT currently not routinely available in Most clinics as yet, but it has great potential in future cases of head and neck cancer.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
305
305
https://ijmp.mums.ac.ir/article_12960_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12960
Prediction of the response to repetitive transcranial magnetic stimulation by spectral powers of prefrontal regions of brain.
Ahmad
shakeri
Ahvaz Jundishapur university of medical sciences, medical physics department, Ahvaz, Iran
author
Ali
Yadollahpour
Ahvaz Jundishapur university of medical sciences, medical physics department, Ahvaz, Iran
author
text
article
2018
eng
Introduction:
Quantitative assessments of the effects induced by repetitive transcranial magnetic stimulation (rTMS) are crucial to develop more efficient and personalized treatments. Objectives: To determine the spectral powers of different subbands of EEG correlated with treatment response to rTMS.
Materials and Methods:
the spectral powers of different subbands of EEG correlated with treatment response to rTMS. Methods: In an open label study 10 patients with intractable major depression received a ten session 20 Hz rTMS over left dorsolateral prefrontal cortex. The EEGs were recorded in all subjects prior and post intervention using a 19-channel EEG system. Hamilton depression rating scale (HAM-D) was also used to determine treatment response. The rTMS protocol consisted of daily one session of 60 trains (2.5 s, inter-train of 17.5 s) at 120% MT for 5 consecutive days per week and 2 weeks. Absolute and relative powers in all electrodes for delta (0-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), sensorimotor rhythm (SMR)(12-15 Hz), beta (15-20 HZ), and high beta (20-28 Hz) were compared prior and post intervention in the responders. Spectral powers of prefrontal and sensorimotor regions of brain predict response to repetitive transcranial magnetic stimulation
Results:
In the responders (n=5), absolute powers of alpha in F3, F4, C3, and C4 electrodes, absolute power of theta and alpha sub-bands in C4 electrode significantly changed (P<0.05). In the SMR band, absolute powers in the Fp1, Fp2, F3, F4, F7, FZ, C3, and C4 significantly changed (P<0.05). In beta subband, relative power in C4 and absolute power in Fp1, Fp2, F4, CZ, and C4 significantly changed (P < 0.05).
Conclusion:
The spectral powers of particular sub-bands in prefrontal cortex and sensorimotor areas can predict response to rTMS treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
306
306
https://ijmp.mums.ac.ir/article_12961_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12961
Gold nanoparticles can induce more apoptosis and double strand breaks on HT-29 cells irradiated by 18 MV photons
Mansour
Zabihzadeh
Nanotechnology Research Center, Faculty of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Clinical Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Ali
Teimoori
Assistant Professor, Department of Virology, School of Medicine, Hamedan University of Medical Sciences, Hamedan, Iran.
author
Vahid
Bayati
Associate Professor, Department of Anatomical Sciences, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Zahra
Ramezani
Associate Professor, Department of Medicinal Chemistry, Faculty of Pharmacy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mojtaba
Hoseini- Ghahfarokhi
Department of Radiology and Nuclear Medicine, School of Para Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
text
article
2018
eng
Introduction: To increase therapeutic ratio, using radio-sensitizers is recommended and nowadays some types of them are utilized clinically. In recent years, Gold nanoparticles (GNPs) were considered as radio-sensitizers in many studies due to high atomic number. Although theoretical works showed that GNPs have an insignificant effect at MV energies, some In-vitro and In-vivo studies have proven promising result for using GNPs at the energy range. The work aims to investigate the effect of GNPs on apoptosis induction and double strand breaks (DSBs) incidence for colon cancer cell line (HT-29) at 18 MV energy.
Materials and Methods: The GNPs were synthesized by seeding-growth method. To determine the morphology and size distribution of the synthesized GNPs, transmission electron microscopy (TEM) was used. The cytotoxicity of GNPs on HT-29 cells was assessed by MTT method in various concentration of GNPs. Moreover, the uptake extent of the nanoparticles into the cells was measured by graphite furnace atomic absorption spectroscopy (GF-AAS). The cells irradiation was done by 18 MV photons after incubation with GNPs. For apoptosis test, 24 h after irradiation, the cells were prepared and read by flowcytometer. As a well-known biomarker of DSBs in cells, γ-H2Ax foci formation were investigated by flowcytometer.
Results: The mean size of synthesized GNPs was 24.75 nm and standard deviation 3.6 nm. TEM images showed spherical like shape for the GNPs. The cytotoxicity of GNPs on Ht-29 cells showed a time-dependent manner so that it was lower for incubation time 48 h than 24
h. Additionally, by increase in GNPs concentration the viability rate of the cells was reduced. The uptake results also exhibited a time dependent pattern and it reached to the maximum after 12 h of incubation time. Apoptosis test showed that the GNPs treated group has significantly more apoptotic cells than other group (P<0.05). Moreover, GNPs caused to forming more γ-H2Ax foci in 18 MV irradiated HT-29 cells.
Conclusion:
Considering result of apoptosis and γ-H2Ax foci formation tests, it seems the GNPs have a great potential to utilize as radio-sensitizer for colon cancer cells at 18 MV energy. However, it needs to study the effect under various conditions as well on animal models.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
307
307
https://ijmp.mums.ac.ir/article_12962_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12962
Evaluation of the effective dose during PBFT for brain cancer: A Monte Carlo Study
Tayebeh
Akbarzadeh
Department of Medical Radiation Engineering, Faculty of engineering, Islamic Azad University, Tehran-Iran
author
Yaser
Kasesaz
Assistant professor, Atomic Energy Organization Of Iran, Nuclear Science and Technology Research Institute (NSTRI)
author
Asghar
haddadi
Assistant professor, Department of Medical Radiation Engineering, Faculty of Engineering, Islamic Azad University, Tehran- Iran
author
text
article
2018
eng
Introduction: Recently, an approach exploiting the proton therapy biological enhancement by using Boron atoms injected inside a tumor, has been proposed. Three alpha particles with an average energy around 4MeV are emitted from the point of reaction between a proton and boron. In addition, the 719 keV prompt gamma emitted by the proton Boron fusion reactions can be used for on-line proton beam imaging purposes. Materials and Methods: We simulated a proton beam passing through the Snyder head phantom with and without a boron uptake region (BUR) in the tumor to investigate the amplification of the proton’s maximum dose level using a Monte Carlo simulation. The proton’s maximum dose level obtained for different proton energies with considering distinction physical conditions (i.e. location and thickness of BUR, boron concentration). The percentage depth dose (PDD) of the proton in the Snyder phantom without the BUR obtained using the F6 tally. However, the counting of additional proton by alpha particle is based on the results by using F4 tally. The absorbed dose due to three alpha particle and proton components acquired for scalp, skull, tumor and brain. Results: The aim of this study is to compare the effectiveness between proton boron fusion therapy (PBFT) and proton therapy and to analyze dose escalation using a Monte Carlo simulation in the brain cancer. When the portion of the proton’s maximum dose (Bragg- peak) is included at tumor region, which is BUR, observed a dramatic therapy effect with less damage to normal tissue. The peak value of maximum dose level when the boron particle was accurately labeled at the region was 185% among the energies. Conclusion: The PDD of the proton beam from the Snyder phantom including the BURs shows more efficient than that of conventional proton therapy on tumor region. The utility of PBFT was verified using the simulation and it has a potential for application in radiotherapy. When the portion of the proton’s maximum dose (Bragg-peak) is included at tumor region, which is BUR, observed a dramatic therapy effect with less damage to normal tissue.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
308
308
https://ijmp.mums.ac.ir/article_12963_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12963
Fabrication of anthropomorphic phantoms for use in total body photon irradiation and total skin electron irradiation studies
Shaghayegh
Fahimi Monzari
Student of Physical Medicine, Physical Medicine department, Tehran University of Medical Science, Tehran, Iran.
author
Ghazale
Geraily
PhD of Physical Medicine, Physical Medicine department, Tehran University of Medical Science, Tehran, Iran.
author
Heydar
Toolee
PhD of Anatomy, Anatomy department, Tehran University of Medical Science, Tehran, Iran.
author
text
article
2018
eng
Introduction: Total Skin Electron Therapy (TSET) and Total Body Irradiation (TBI) are kinds of treatment which use electron and photon beams to treat special types of cancers. The aim of these techniques are to deliver uniform dose to the entire skin while minimizing delivered dose to organs at risk. To check the homogeneity of dose delivery in TBI and TSET, using a humanoid phantom is necessary. Aim of this study is to manufacture an anatomical model of an adult male included lower limb to evaluate the dose distribution in dosimetry measurements of radiotherapy. In addition, we want to offer a method for low-cost fabrication of an anthropomorphic phantom by tissue substitute material compared to similar commercial phantom.
Materials and Methods: To design the phantom, CT scan images of the atomic energy organization RANDO phantom were our reference. Also AutoCAD, Corel and Solid works software were used. This Phantom has five different heterogeneities including air, Plexiglas for Soft tissue substitute, Polytetrafluoroethylene (PTFE) for Bone tissue substitute, Cork for Lung tissue and Polyethylene for designing three organs such as rectum, bladder, and prostate and also has four sections including head and neck, trunk, pelvis and two legs. After construction, the phantom was validated by CT number conformity and relative electron density determination methods (such as from tissue's Linear attenuation coefficients and their CT numbers) compare to standard values. In addition, percentage error of the relative electron density calculated from the linear attenuation coefficient and the CT number were compared.
Results: The constructed anthropomorphic male RANDO Phantom consists of 175 layers with 1 cm thickness, 175 cm height and 72 kg weight. validating the constructed phantom by two methods demonstrate good agreement between tissue substitute materials in phantom structure in compare to standard values that suggested from ICRU44. percentage error difference in the relative electron density calculated from the linear attenuation coefficient and the CT number was in a good range between 0 -5.91. In the other hand there is no significant difference between reD obtained from these two methods and real tissue electron density (P-value < 0/05) so it can be concluded that both methods are reliable for phantom validation process.
Conclusion: Lower limbs can be a good bench mark for evaluation for patients with skin cancers so design of the whole body phantom with two lower limbs is very necessary. The another advantages of this study is use of high stability material that do not destroy over time. Finally, the constructed phantom in this study is recommended for TBI and TSET.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
309
309
https://ijmp.mums.ac.ir/article_12964_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12964
Determination of the flux of a neutron radioisotope source through gold activation method
Alireza
Sadremomtaz
Department of physics, University of Guilan, Rasht, Guilan, Email: Sadremomtaz@yahoo.co.uk
author
Peyvand
Taherparvar
Department of physics, University of Guilan, Rasht, Guilan, Email: p.taherparvar@guilan.ac.ir
author
Sepideh
Gholami
Faculty of Science, University of Guilan, Rasht, Guilan, Email: Gholamisepideh6@gmail.com
author
text
article
2018
eng
Introduction:
In recent years, the use of neutrons has increased in various fields such as medicine and industry. One of the important applications of neutrons is in medical research. Neutrons have greater linear energy transfer than gamma rays and are considered more dangerous radiation. Hence, the detection and determination of neutron dose is a very important and vital issue. For determination of neutron dose, measurement of its intensity or flux is essential. One of the ways of neutron flux determination is using of gold foil activation method. In this method, the activity of the irradiated foil is proportional to the neutron flux. The gold foil is activated by reaction 197Au (n,γ) 198Au because of the thermal neutron capture,. In the decay of activated gold, a gamma radiation of 411.8 keV is released with a probability of more than 95%, that By measuring the area below the peak associated with this energy, by the NaI(Tl) detector, the activity of gold and then the neutron flux is determined.
Materials and Methods:
In this paper, an 18 carat gold foil was used to measure the flux of a neutron radioisotope source Ra-Be in the nuclear laboratory of the Faculty of Science of Guilan University.
Results:
After irradiation, the gold foil was counted by NaI(Tl) detector and its flux was determined
Conclusion:
Finally, by comparing the measured flux and the flux in the Ra-Be neutron source catalogue, it is resulted that the mentioned method has a good accuracy in determination of the flux of the neutron source.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
310
310
https://ijmp.mums.ac.ir/article_12965_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12965
Title Design of light element analysis system in BNCT and every NCT
Jamal
Amiri
Department of Radiotherapy, Faculty of Paramedical Sciences, Kurdistan University of Medical Sciences, Sanandaj, Iran
author
text
article
2018
eng
Introduction:
The Monte Carlo simulation is used to enhance reliability in the experiments related to nuclear instruments. in addition, that is used to calculate the different components of the neutron and gamma ray fluxes in boron neutron capture therapy(BNCT) and neutron capture (NCT)applications. BNCT is one of the methods in radiotherapy, that is used the neutron beam for kill the cancer cells. The neutron activation analysis(NAA) is the method for identify light elements that the neutron is captured with light elements nucleus and emits characteristic gamma rays.
Materials and Methods:
the MCNPX code was used for calculation. Boron and other light elements exist in the liver tissue. The BNCT special set geometry was designed. In this designed, light elements analysis is performed simultaneously with the neutron therapy. The effective parameters such as source location, source type, detector location, detector material, patient couch, energy of source, moderator, collimator type, length and thickness of collimator, distance between sample and source, opening of collimator, geometry and location of detector was designed.
Results:
the best neutron source for BNCT and light element analysis is expanded neutron spectrum produced by the reactor with Paraffin moderator. Neutron Source Generator with every moderator had low efficiency. Collimator made of graphite, graphene and carbon compounds had better neutron output spectrum. Sodium iodide detector is suitable for the detection of light elements gamma rays. The collimator length 20 cm and thickness 6cm. The detectors are placed in a cylindrical arrangement and They should not be exposed to direct neutron radiation.
Conclusion:
the MCNP study is one of the best methods for BNCT and NCT. the NAA and BNCT is possible Performing Simultaneously. The expanded neutron spectrum from reactors is suitable for NAA and BNCT.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
311
311
https://ijmp.mums.ac.ir/article_12966_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12966
Alterations in Hippocampal Functional Connectivity in patients with Mesial Temporal Sclerosis
Fatemeh
Baniasad
MSc, Department of Medical Physics and Biomedical Engineering, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences
author
Fatemeh
Eivazi
PhD, Institute for Cognitive Science Studies, Shahid Beheshti University, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences
author
Roya
Sharifpour
MSc, Department of Medical Physics and Biomedical Engineering, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences
author
Mohammad-Reza
Nazem-Zadeh
Assistant Professor, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences
author
text
article
2018
eng
Introduction:
Medial temporal sclerosis (MTS) is a form of mesial temporal lobe epilepsy (mTLE). It is typically characterized by structural alterations in hippocampus (HC) and related mesial temporal lobe (MTL) network. Resting state functional connectivity (RSFC) is considered an ideal technique in quantifying the dysfunction and maladaptation in MTL network. It is well- demonstrated that the seizure effects go beyond epileptogenic zones and alterations in connectivity are fairly widespread across cortical and subcortical regions. This study aims to assess the alterations in RSFC in hippocampus in patients with MTS.
Materials and Methods:
Resting state Functional magnetic resonance imaging was performed during interictal activity on 18 patients with MTS (7 patients with right and 11 patients with left MTS). Preprocessing included removing the first 10 time points, slice timing, head motion correction, normalization and removing the linear fMRI signal trend. Processing and statistical analysis were conducted using DPARSF and MATLAB, respectively. For all patients, the RSFC for both right and left hippocampi to 116 regions of interest (ROIs) were calculated and statistically analyzed. Connectivity of left and right hippocampi were compared between left and right MTS cohorts using paired t-student test.
Results:
Statistically significant differences between left and right hippocampi were observed in 1 and 15 ROIs for right and left MTS cohorts, respectively. Left paraHippocampus was the only ROI with significant difference in RSFC with right and left hippocampi in right MTS patients. Left Amygdala, Right Rolandic_Ope, Cingulum_posterior, paraHippocampus, Occipital_Inf, Fusiform, Parietal_Inf, Supra Marginal, Angular, Heschl, Temporal_Sup, Temporal_Mid, Temporal_Pole_Mid, Temporal_Inf gyri, and Cerebelum_4_5 showed significant difference between their connectivity with respect to left and right hippocampi in patients with left MTS.
Conclusion:
Left MTS may be associated with more extensive network impairment compared to right MTS. This result is in agreement with previous studies (Pereira et al and Doucet et al). Our findings also show that the behaviour of left paraHippocampus in the alteration in RSFC can be used as an indication for Right MTS.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
312
312
https://ijmp.mums.ac.ir/article_12967_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12967
Assessment of secondary neutron dose due to dental restorations in head and neck radiation therapy
Mona
Azizi
PhD. Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran, Tel: 05144013365, Fax: 05144013365 monaazizi68@gmail.com
author
Mehdi
Ghorbani
PhD. Biomedical Engineering and Medical Physics Department, faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran, Tel: 02122439941, Fax: 02122439941, mhdghorbani@gmail.com
author
Ali Asghar
Mowlavi
Professor. Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran, Tel: 05144013170, Fax: 5144013365, aa_mowlavi@yahoo.com
author
Zeinab
Mohammadpoory
PhD. Biomedical Engineering Department, Hakim Sabzevari University, Sabzevar, Iran, Tel: 05144012605, Fax: 05144012605
author
text
article
2018
eng
Introduction: One of scientific concern is increasing of unwanted neutron dose to the patient, in head and neck radiation therapy due to the presence of some isotopes in dental restorations and head of medical linac. The aim of this study is to measure the equivalent dose of thermal and fast neutron due to head of Siemens Primus Linac and a healthy tooth, Amalgam, Ni-Cr alloy and Ceramco irradiated by 15 MV photon beams.
Materials and Methods: To evaluation of production of secondary neutrons due to the various dental restorations and head of medical linac in in 15 MV photon beam of Siemens Primus linac (Siemens AG, Erlangen, Germany), three commercial dental materials were used. This dental phantom configuration was consisted of combination of two healthy teeth, a tooth filled with Amalgam, a Ni-Cr alloy and Ceramco which they were collected randomly from dentistry clinics. The dental phantom was placed in depth of 1 cm in PMMA. In order to score of thermal and fast neutron equivalent doses, CR-39 detector was used. All the results of equivalent dose are considered to the delivery of 100 cGy dose at the maximum depth of
3.1 cm in the PMMA phantom with 15 MV photon beam and 10 × 10 cm2 field.
Results: It is found out the maximum fast neutron dose was scored on the phantom surface which is related to head of Siemens primus linac. About the dental restorations, maximum fast neutron equivalent dose is related to amalgam, Ceramco and Ni-Cr alloy with amount of
0.19 mSv, 1.04 mSv, and 0.97 mSv at depth of 1.8 cm, respectively and then they decrease as the depth increases. The minimum amount of thermal neutron dose was measured on the surface of phantom. In case of denture samples, after dental phantom, the trend of the thermal neutron dose is reduced. The results indicated that maximum amount of thermal equivalent dose is related to Amalgam, Ceramco and Ni-Cr alloy and is equal to 1.45 mSv,
1.38 mSv, and 1.32 mSv, respectively.
Conclusion: This study indicates an interpretation about photoneutron production in presence of the various dental restorations and head of Siemens primus medical linac. Presence of some elements in metallic dentures and head of medical linac, on the path of high photon beam can leads to the additional dose in the patient body. According to these results, thermal and fast neutron equivalent dose are started with an increase then they are reduced at depths after the dental restorations. Therefore, according to these results, it is recommended that some attempt should be carried out to make sure that the dental restorations are not in the path of primary photon beam with high energy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
313
313
https://ijmp.mums.ac.ir/article_12968_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12968
Wavelet Transformation
Alireza
Sadremomtaz
Professor, Physics Department , Factually of Science, University of Guilan, Rasht, sadremomtaz@guilan.ac.ir
author
Ebrahim
Siri
B.Sc. Student, Factually of Science, University of Guilan, Rasht, pouya.si74@gmail.com
author
text
article
2018
eng
Wavelet transformation is one of the most practical mathematical transformations in the field of image processing, especially image and signal processing. Depending on the nature of the multiresolution analysis, Wavelet transformation become more accessible and powerful tools. In this paper, we refer to the mathematical foundations of this transformation.
Introduction:
The wavelet transform has been proven effective for image analysis, data compression and feature extraction. This linear transform is a powerful tool for time (space)-frequency analysis of signals, especially images. The expansion of a signal into several frequency channels generates a joint representation in time and frequency domains. The wavelet transform does provide a multiresolution decomposition and representation of an image at given resolutions. It is computed by expanding a signal into a family of functions which are the dilations and translations of a unique function called the basic wavelet. It is also interpreted as a decomposition into a set of frequency channels having the same bandwidth on a logarithmic scale.
Materials and Methods:
Using a one-dimensional wavelet transform and its mathematical foundations, the effect on the image resolution was compared to the short time Fourier transform.
Results:
In the transformation of the wavelet, the finite signal does not convert the Fourier transform, and thus the individual peaks or, in other words, the negative frequencies are not calculated.
Conclusion:
The continuous wavelet transform can be presented as an alternative to the short time Fourier transform, and aims to resolve the resolution problems.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
314
314
https://ijmp.mums.ac.ir/article_12969_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12969
Calculation of absorbed dose rate in the lungs, ribs and skin by the mammosite applicator in breast cancer brachytherapy with MCNP
Fatemeh
Mahdavi
M.Sc. of Medical Radiation Engineering, of Science and Research University of Tehran
author
Alireza
Shirazi Hosseini Dokht
Professor of Physics and Medical Engineering Department of University of Tehran
author
Mahdi
Sadeghi
Professor of Medical Physics Department of Medical University of Iran
author
text
article
2018
eng
Introduction: Breast cancer is the most common cancer among women. Brachytherapy is one of the ways to treat breast cancer. In brachytherapy treatments, high-dose sources are used in interstitial placement. Here, Iridium-192 is used. This source emits gamma rays with energies ranging from 136 kV to 1060 kV electron volts. The activity of the used spring is 10 Ci. The simulated source here is a cylinder with a length of 0.5 and a radius of 0.017 cm. In this paper, the modeling of a common breast cancer treatment applicator called MammoSite is done by the Monte Carlo simulation code. Then, calculate the amount of doses in the brachytherapy of the breast, target volume (tumor) and the dose rate of the organs at risk of radiation, including lungs, ribs and skin.
Materials and Methods: MCNPX: The MCNPX code: is the based on the Monte Carlo method. The code, with input file information and the use of the cross-section library, solves the problem and produces results in an output file.
MIRD phantom: To calculate the dose, a model of the human body is required as a phantom. All organs of the human body are characterized by a detailed description for the calculation of the absorbed dose in this phantom.
Mammosite applicator: This device has a catheter that can be attached to the high dose rate afterloading machine that connect to the source. The end of catheter is surrounded by a balloon that can be filled with normal saline or water. The balloon is placed in the lumpectomy cavity where the 34Gy can reach the treatment site. The most common size of this balloon is 4-5 cm and 5-6 cm, which has a volume between 34-113 cm cubic meters.
Results: The absorbed dose by the organs of the skin, ribs and target volume (tumor) is constant when the breast is treated right or left, dose rate of: target volume= 0/7, ribs=0/026, skin=0/009 Gy/min, but when the breast is treated right, the absorbed dose in: right lung=0/045, right breast=0/726, left lung=0/005, left breast=0/006 Gy/min and when the breast is treated left, the absorbed dose in: left lung=0/044, left breast=0/726, right lung=0/006, right breast=0/0068 Gy/min.
Conclusion: As expected, absorbed dose in the target volume and the treated breast was the highest and after that the lung received the same significant dose. Indeed, the higher the organ absorbed dose to the target dose rate is better. When the right breast was treated, the right lungs, ribs, and skin had the highest absorbed dose to the dose received by the tumor And when the left breast was treated, the left lung, ribs and skin had the highest absorbed dose to the dose received by the target valume or tumor.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
316
316
https://ijmp.mums.ac.ir/article_12970_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12970
Advanced quantitative MRI radiomics features for recurrence prediction in glioblastoma multiform patients
Ghasem
Hajianfar
MSc student of Medical Physics, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Isaac
shiri
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
Department of Biomedical and Health Informatics, Rajaei Cardiovascular, Medical & Research Center, Iran University of Medical Science, Tehran, Iran
author
Hassan
Maleki
Department of Biomedical and Health Informatics, Rajaei Cardiovascular, Medical & Research Center, Iran University of Medical Science, Tehran, Iran
author
Abbas
Haghparast
Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Mehrdad
Oveisi
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
Department of Computer Science, The University of British Columbia, Vancouver, British Columbia, Canada
author
text
article
2018
eng
Introduction:
Advanced quantitative information such as radiomics features derived from
magnetic resonance (MR) image may be useful for outcome prediction, prognostic models or response biomarkers in Glioblastoma (GBM). The main aim of this study was to evaluate MRI radiomics features for recurrence prediction in glioblastoma multiform.
Materials and Methods:
86 patients with recurrent GBM who underwent MRI were subjected to this study. The axial T1-weighted contrast-enhanced and axial T2-weighted FLAIR images were included for analysis. All images were preprocessed by different bin width (32, 64 and 128). For each lesion we manually segmented Active, Necrosis and whole Tumor region in T1-CE and Edema region in T2-FLAIR. 105 quantitative 3D features and texture based on intensity histograms (IH), gray level run-length (GLRLM), gray level co-occurrence (GLCM), gray level size-zone texture matrices (GLSZM), neighborhood-difference matrices (NDM), and geometric features were extracted from the 3D-tumor volumes of each segment. Random Forest (RF) machine learning with 10-fold cross validation was used to recurrence prediction in GBM.
Results:
Area under ROC curve (AUC) as an assessment index on RF with bin width of 32, 64 and 128 achieved in Active (0.616, 0.586, 0.509), Necrosis (0.521, 0.521, 0.545), whole Tumor (0.639,
0.602, 0.547) and Edema regions (0.629, 0.669, 0.621), respectively.
Conclusion:
The main purpose of this assay was to assess the power of MRI radiomics features in GBM patients for recurrence prediction. The proposed method can effectively predict recurrence in GBM by application of advanced MRI quantitative radiomics features and machine learning.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
319
319
https://ijmp.mums.ac.ir/article_12974_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12974
Evaluation of the efficacy of hysterosalpingography test for the removal of fallopian tube obstruction and infertility treatment in women in Sistan and Baluchestan province
Hamideh
Moghimi
B.S. student of radiology, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Iran
author
Jalal
ordoni
MSC of Radiobiology, Department of Radiology, Faculty Member of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran
author
mahbobeh
golestaneh
B.S. student of radiology, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Iran
author
meisam
kamali
B.S. student of radiology, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Iran
author
fatemeh
sayadi
B.S. student of radiology, Department of radiology, Faculty of Para medicine, zahedan University of Medical Sciences, zahedan. Iran
author
text
article
2018
eng
Introduction: Infertility has increased in Iran due to age, inappropriate nutrition and marriage. One of the causes of infertility is the blockage of the uterine tubes. Hysterosalpingography(HSG) is a non-invasive method used to examine the uterus of the uterus. In this method, by inserting the contrast agent through the vagina into the uterus, there is a possibility of partial occlusion opening in the tubes. The purpose of this study was to investigate the effect of HSG on the prevention of uterine tube obstruction and infertility treatment.
Materials and Methods: Analysis of 25 patients from 60 patients with minor tube obstruction showed that their fertility was related to HSG. 9 of the women who had severe tubal obstruction did not have any effect on these procedures, but 16 others had been blocked by their HSG method after 4 months.
Results: The effect of age, weight, nutrition and culture level on tube obstruction was investigated. Inappropriate nutrition and aging, the most important causes of increased tube obstruction in women studied in this study. The level of culture and weight had an indirect effect on tubular obstruction. Also, the effect of the HSG method on the removal of mild tubal obstruction and treatment of infertility was significant, with 16 of 25 patients being ingested.
Conclusion: The tube obstruction was meaningful in women with age and inappropriate nutrition. As the age increases, the bonding probability of the tubes increases. These findings suggest that the HSG method plays an important role in the treatment of infertility And it can be suggested to women with infertility with minor tubular obstruction.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
320
320
https://ijmp.mums.ac.ir/article_12975_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12975
Comparative Study between Electronic Portal Imaging Device (EPID) and Cone Beam Computed Tomography (CBCT) for Radiation Treatment Verifications
Eyachew
Misganew Tegaw
PhD student in Medical Physics, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, International Campus (TUMS-IC), Tehran, Iran
author
Ghazale
Geraily
Doctor of Medical Physics, Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
Getu
Ferenji Tadesse
PhD student in Medical Physics, Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, International Campus (TUMS-IC), Tehran, Iran
author
text
article
2018
eng
Introduction:
Electronic Portal Imaging Device (EPID) and Cone Beam Computed Tomography (CBCT) are the preferred tools of Image Guided Radiotherapy (IGRT) and Dose Guided Radiotherapy (DGRT) which have been used for Radiotherapy treatment verifications. As a result, the number of publications dealing with these two tools for radiation treatment verification has increased considerably over the past years. This paper aims to compare and contrast the overall differences and similarities of EPID and CBCT tools based on their set-up verification accuracy, dosimetric verification accuracy, calibration and quality control methods, image quality, dose measurement, calculation, and evaluation methods for radiation treatment verifications.
Materials and Methods:
The relevant articles published in English were searched based on the keywords of EPID and CBCT for radiation treatment verifications using PubMed, EMBASE, Scopus, and Web of Science databases and finally exported to EndNote for screening, downloading, and reference management processes.
Results:
A total of 2512 articles were searched and subsequently screened by removing duplications and reading title and abstract to identify original articles that directly related with radiation treatment verifications using EPID and CBCT for different cases. This yielded 226 relevant articles. After downloaded and read full articles, only compared results between EPID and CBCT treatment verifications were selected. This yielded, a final total of 23 articles to be included for this work.
Conclusion:
EPID and MV-CBCT have almost equal potential to indicate the set-up error but since they used the LINAC’s energy, no cross-calibration procedure is needed because the imaging geometry is the same as the treatment geometry though both of them have poor image quality. The image quality of KV-CBCT is superior to both EPID and MV-CBCT and is better to indicate the set-up error. CBCT in conjunction with energy fluence maps from EPID could be used to verify the dose delivered. In this instance, a cross-calibration between the KV CBCT and EPID would be required which would not be necessary with MV CBCT. Though MV CBCT handles inhomogeneity better, soft tissue visualization is superior with KV CBCT. EPID is used to calibrate the LINAC machine. Generally, both EPID and CBCT have their own different advantages and need further study to solve their limitations.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
321
321
https://ijmp.mums.ac.ir/article_12976_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12976
Assessment the effect of CT localizer parameter on radiation dose and image quality of GE CT spiral images, A phantom study
Yazdan
Salimi
Department of biomedical engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
MohammadReza
Deevband
Department of biomedical engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Pardis
Ghafarian
Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
PET/CT and Cyclotron Center of Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Using computed tomography (CT) is increasing significantly in Iran and worldwide. Reduction of CT's radiation dose is a critical concern. The aim of this study was evaluating the effect of localizer kVp on spiral CT images when the tube current modulation (TCM) is activated.
Materials and Methods:
A special wedding cake phantom with circular intersection and diameters of 15 to 40 cm was scanned on a GE VCT 64 slice scanner. The whole length of phantom (84cm) was scanned with kVps of 80,100,120 and 140. The image noise was measured in SD of Ct numbers and the radiation dose was measured in term of CTDIvol. The tube current variation through the Z-Axis was extracted from DICOM images.
Results:
Function of TCM was affected by changing the scout view parameters. By increasing the localizer kVp the average used tube current was decreased and image noise was increased (8-32%, p<0.05); especially for larger phantom diameters and wide kVp difference between localizer and spiral kVps (up to 32%). On the other hand, the localizer with lower kVp than spiral leads to higher CTDIVOLs and lower image noises. The image noise was closer to chosen Noise Index when the localizer and spiral scan were in the same kVps.
Conclusion:
The attenuation of localizer X-ray is the criteria of tube current changing in spiral CT. The attenuation is variable in different kVps of X-ray. The ability of TCM system was the best in offering the constant image noise when the localizer and spiral scans were in the same kVp. Inappropriate localizer kVp may increase the patients’ radiation dose or degrade the image quality by miscalculations in TCM system
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
323
323
https://ijmp.mums.ac.ir/article_12977_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12977
Evaluation of Patients’ effective dose in nuclear medicine department of Isfahan in order to define a local reference level
Yazdan
Salimi
Department of biomedical engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mohsen
Cheki
Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
MohammadHosein
Jamshidi
Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Masoud
Moslehi
Department of Nuclear Medicine, Seyedoshohada Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Jalal
Ordoni
Department of Radiologic Technology, Faculty of Paramedicine, Zahedan University of Medical Sciences, Zahedan, Iran
author
text
article
2018
eng
Introduction:
Nowadays, nuclear medicine (NM) imaging indications in medical practice is raising. A practical step to get closer to the optimization rule is collecting data about patients’ exposure and definition of guidance levels. The aim of this study was definition of local reference level in Isfahan city.
Materials and Methods:
Questionnaires were given to two NM departments of Isfahan Hospitals. The data of age, gender, weight, type and activity of used radiopharmaceutical were collected for protocols of Bone (TC-MDP), Kidney (TC-DMSA), Kidney (TC-DTPA), Kidney (TC-EC), Thyroid (TC- Pertechnetate), Lung (TC-MAA), Cardiac (TC-MIBI) for adults and Bone (TC-MDP), Kidney (TC-DMSA), Kidney (TC-EC), Kidney (TC-DTPA) for pediatrics. The cardiac scan is performed in two-day Stress-Rest protocol.
Results:
1540 patients (243 pediatric and 1297 adults) were included. The average injected activities in pediatrics were 5, 3, 2 and 5 mili-curies for MDP, DMSA, EC and DTPA respectively. These injected activities impose doses of 1.82, 1.91, 1.68, 2.32 mili siverts for pediatric patients. For adult patients the average activities were 22.5, 6.5, 8, 4, 12, 4, 21.5 and 19.5 mili-curies for protocols of MDP, DMSA, EC, MAA, DTPA, Pertechnetate, MIBI-Stress and MIBI-Rest respectively. Which impose effective total body doses of 4.75, 2.12, 2.07, 1.62, 2.17, 1.92, 6.29 and 6.49 mili siverts to adult patients respectively.
Conclusion:
It is the first study done in all ages to evaluate patients’ dose in NM in Iran. In these departments injected activities were based on patient weight and protocols were adapted with dose charts exists for adult and pediatric patients; so variations in doses were minimum. These charts were offered to radiation workers based on acceptable image quality, SPECT system sensitivity and patient dose. In comparison with guidance levels of other countries, patients’ received dose during in these Isfahan N.M centers were comparable with international diagnostic reference levels reported by the European commission and mettle et al 2008 and study of Niksirat et al, 2014 in Mazandaran. Injected activities for cardiac imaging are higher (40%) from study of Salimi et al 2015 in Tehran. This variations through the administrated dose in country makes it more critical to plan a national survey in order to offer a guideline in this country.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
324
324
https://ijmp.mums.ac.ir/article_12978_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.12978
Estimating the radiation dose of non-radiation workers from nuclear medicine patients
Yazdan
Salimi
Department of biomedical engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
MohammadReza
Deevband
Department of biomedical engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
As a valuable imaging modality, Nuclear Medicine (NM) indications is raising in clinical practice. The remained portion administrated radioactive material in patients’ tissues is a critical issue, especially when the procedure is performed in hospitalized patients, where the non-radiation workers present. The aim of this study was evaluation the dose of non-radiation workers staff from hospitalized NM patients.
Materials and Methods:
Ninety-one patient were selected. Four procedures of Cardiac (TC-MIBI), Bone (TC-MDP), Renal (TC- DTPA) and Lung (TC-MAA) were chosen. The one-day protocol is a clinical routine in this NM department for hospitalized patient referred for cardiac scan. By means of calibrated ionization chamber the dose rate in term of Micro-Sivert per hour (µSv/h) was measured on three positions against patient’s body. On the chest wall, 30 cm distance and 1.5 meter away from the patient. These measurements were done on five phases of immediately after injection, 30 minutes, 1 hour, 3 hours and 4 hours after injection of the radiopharmaceutical. All of measurements were in place without radiation from the other patients and medical sources where the only source was the indicated patient.
The total absorbed dose of patients were estimated by equation Dose= Dose rate × time. The integral of exposure time at different distances and positions were estimated for average situation in other departments.
Results:
Each of hospital wards referred averagely 3 patients to NM department per month. The average measured dose rate at the chest wall were 92,120, 84, 22 and 6 µSv/h at time of injection, 0.5, 1, 3 and 4 hours after injection respectively. The dose rate before leaving the NM department at chest wall, 30 cm from patient and 1.5 meters anterior away from patient were 5.5, 4 and 3 µSv/h respectively. On monitoring and questionnaires, each personnel exposed to patient’s radiation at 1.5 meter for 1.5 hours and 35 minutes at 30 cm away from the patient. The estimated dose of staff were 6.8±3.6 (2.1 to 8.2)
µSv/h. The most exposure was for ICU and CCU ward where the design of department and sensitivity of patient care leads to more exposure time. CCU ward has referred the most patients (average 10 patients per month) to NM department. The most radiation dose was for bone scan and then cardiac scan. The average received dose is 244 µSv per year for staff.
Conclusion:
Although this study is a rough estimate about the staff dose but, the exposure of hospital wards from Nuclear medicine patients is negligible according to radiation protection limits for public, but It is recommended to design appropriate policy about patient release and clearance of radioactive materials. It is critical to have completing study by personal dosimeters such as film badge or TLD to accurately measure absorbed dose.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
325
325
https://ijmp.mums.ac.ir/article_12979_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12979
Effect of replacing cochlea contour with inner ear contour on cochlea dose-volume calculations in conventional 2 dimensional and conformal 3 dimensional radiotherapy of brain
Somayeh
karimi
Medical Physics Department, Isfahan University of Medical Sciences, Isfahan, iran, Mob: 09127879809
author
alireza
Amouheidari
Isfahan Milad Hospital , Deputy Manager in Research & Education, Head, Department of Radiation Oncology , Isfahan ,Iran ,amouheidari@yahoo.com , amouheidari@imsh.ir ,Tel: 031 37774001-8,Mob: 0098 913 3288345
author
parvaneh
shokrani
Professor of Medical Physics , Medical Physics Department , Isfahan University of Medical Science ,Isfahan, ,Iran email: shokrani@med.mui.ac.ir , Mob 09133158618
author
text
article
2018
eng
Introduction:
Sensorineural hearing loss (SNHL) is one of the possible complications of radiotherapy treatment of brain tumors. The auditory system of patients with brain tumors often is placed inside of radiation field and receives a significant amount of radiation dose resulting in hearing loss. The purpose of this study was to compare contouring and delivery dose to cochlea and inner ear in two techniques of 3D conformal radiotherapy (3DCRT) vs 2D conventional radiotherapy in patients with brain tumors
Materials and Methods:
This was a prospective study. Forty-three patients (23male and 20 female) who received radiotherapy for brain tumors in the radiation oncology department of Isfahan Milad Hospital during 2016 entered the study. Computerized tomography (CT) images of the patients were used for contouring of cochlea and inner ear by radiation oncologist. Dose Volume Histograms (DVHs) for 2D and 3D techniques were compared using TiGRT treatment planning system.
Results:
In 2D technique the mean dose of the cochlea and inner ear was 2624 ± 338.7(cGy) and 2718.3 ± 341.3(cGy), respectively. In 3DCRT technique the mean dose of the cochlea and inner ear was 2507±294.6(cGy) and 2581± 295.6(cGy), respectively. The mean dose of inner ear and cochlea in 3DCRTmethod was %5.3 and %4.6 lower than 2D, respectively Conclusion:
The study of dosimetric parameters of the auditory system in treatment planning of two methods of radiation therapy showed that there was no significant difference between the doses of cochlea and inner ear in 2D and 3D methods ( Pvalues=0.86,0.85).Therefore in treatment planning of these two radiotherapy techniques, contour of cochlea can be replaced by inner ear.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
326
326
https://ijmp.mums.ac.ir/article_12980_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12980
A statistical model for prediction of radiation induced sensorineural hearing loss in radiotherapy of brain
Somayeh
karimi
Medical Physics Department, Isfahan University of Medical Sciences, Isfahan, iran, Mob: 09127879809
author
alireza
Amouheidari
Isfahan Milad Hospital, Deputy Manager in Research & Education, Head, Department of Radiation Oncology, Isfahan, Iran
author
parvaneh
shokrani
Professor of Medical Physics, Medical Physics Department, Isfahan University of Medical Science, Isfahan,
, Iran
author
text
article
2018
eng
Introduction: The purpose of this study was to develop a statistical model for prediction of radiation induced sensorineural hearing loss (SNHL) induced by radiotherapy in patients with brain tumors.
Materials and Methods: CT scan of 18 patients (10 males and 8 females) with brain tumor who were referred to Radiation Center of Milad Hospital in Isfahan in 2017 was used. For each patient, audiometric evaluation was performed before and 12 months after treatment at frequencies of 500-8000 Hz. The cochlea contouring on the patient's CT scan was performed by an oncologist using TiGRT therapy treatment planning system. Dose-volume histograms (DVH) for 2D and 3D treatment plans were calculated and compared. In order to predict SNHL after radiotherapy, a model was developed using patient’s data and regression statistical method based on a logarithmic function. Significance of factors influencing SNHL was also investigated.
Results:
The dose delivered to cochlea was similar in 2D and 3D treatment plans (P values = 0.256). During the 12 months after treatment, relationship between SNHL and cochlea dose, age, hearing threshold before treatment, and sound frequency were evaluated. The developed regression model showed the significance of sound frequency on the relationship between age and dose delivered to cochlea on auditory level of the patients after treatment.
Conclusion:
Effect of dose delivered to auditory system depends on patient’s age and hearing threshold before treatment, as well as sound frequency. The degree of hearing loss in patients was higher at higher frequencies
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
327
327
https://ijmp.mums.ac.ir/article_12981_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12981
Mechanical performance of three-dimensional bio- nanocomposite scaffolds designed with digital light processing for biomedical applications
Saeid
Esmaeili
Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr/Isfahan, Iran
author
Amirsalar
Khandan
New Technologies Research Center, Amirkabir University of Technology, Tehran 15875-4413, Iran
author
Saeed
Saber-Samandari
New Technologies Research Center, Amirkabir University of Technology, Tehran 15875-4413, Iran
author
text
article
2018
eng
Introduction: The need for biocompatible and bioactive scaffolds to accelerate the regeneration and repair of fractured bones has been considered for bone tissue engineering applications during recent decades. The new methods were developed to produce scaffolds to improve the tissue quality, size of cavities, control the porosity and increase the scaffold compressive strength under different loads. The presence of compounds such as hydroxyapatite (HA), which contains calcium and phosphorus ions, is essential for bone marrow transplantation. The use of carbon nanotubes can be considered to improve mechanical, chemical and biological properties, much like bone collagen. However, the construction of bio-nanocomposite scaffold which includes all of the above properties is very important in accelerating bone repair and also in reducing the problems of using other conventional scaffold methods.
Materials and Methods: In this paper, the fabrication of a bio-nanocomposite scaffold with a three-dimensional printing method, digital light processing (DLP) has been investigated. The used compounds of photopolymer resin, carbon nanotubes and hydroxyapatite are solvent by ultrasonic and magnet stirrer, then a scaffold model designed in SOLIDWORKS software applied to the DLP 3D printer.
Results: The addition of single wall carbon nanotubes (SWCNT) increases the compressive strength of the samples more than two times, beside it leads to an increase in the porosity of the samples due to the addition of SWCNTs. The scaffold porosity was recorded around 75 and 85%, which is associated with a proper compressive strength around 2 -4 MPa. Addition of 2.5 to 5 wt% SWCNT to HA and photopolymer resin can leads to a better mechanical performance compared to the pure sample.
Conclusion: The results obtained from this work showed that the above process was successful methodology in preparation of novel scaffold bio-nanocomposites using DLP technique for using in bone tissue engineering.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
328
328
https://ijmp.mums.ac.ir/article_12982_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12982
The microscopic dose enhancement factor measurment of bismuth nanoparticles in external radiation therapy using MRI polymer gel dosimetery
Shiva
Shoobkolaei
Msc of Medical Physics, Department of Medical Physics, Tehran University of Medical Sciences, Tehran, Iran.
author
Nader
Riahi Alam
Professor of Medical Physics, Department of Medical Physics, Tehran University of Medical Sciences, Tehran, Iran.
author
Ali
Shabestani Monfared
Professor of Medical Physics, Radiotherapy Physicist, Babolsar Oncology Hospital, Department of Medical Physics, Babol Univetsity of Medical Sciences, Babol, Iran.
author
Mehdi
Khobi
Associate professor of chemistry, Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction:
Bismuth-based nanoparticles having high atomic number and electron density, besides of being utilized as CT contrast agent, stand as a strongly proposed method for dose enhancement in radiotherapy. Embedded nanoparticle in polymer gel dosimeter poses the first step to assess the dose enhancement capability in nanoparticles. To this end, MAGICA gel dosimeter, which is a modified kind of agarose-added magic gel to obtain more stiffness and stability is appropriate method. This study aims at determining the dose enhancement capability of bismuth nanoparticles in this gel under conventional external radiotherapy.
Materials and Methods:
In current study, the synthesized bismuth nanoparticles approximately with 20 nanometers in diameter and 0.1mM in concentration were injected into MAGICA gel and exposed to 6 MV X-rays beams from linear accelerator simultaneously with control gel samples irradiated in different five doses from 2-10Gy.
Results:
MAGICA polymer gel response against radiation was characterized by comparing R2 in samples lacking nanoparticles and with Bi-NPs. MAGICA response was found to be linear over the entire dose range explored from 2Gy up to 10 Gy. Results indicated the average dose enhancement factor around 9.8% ± 0.02 in the presence of Bi-NPs.
Conclusion:
This study investigated the dose enhancement capability of bismuth nanoparticles in external radiotherapy. As well as, MAGICA polymer gel combined with Bi-NPs was approved as a suitable tool for measuring the enhancement of radiation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
329
329
https://ijmp.mums.ac.ir/article_12983_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12983
Designing Optimal Bias Voltage for Radiotherapy Diamond Dosimeter
Abolfazl
Zanghaei
Biomedical Engineering and Medical Physics Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Ahmad
Mostaar
Biomedical Engineering and Medical Physics Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Shahrokh
Naseri
Medical Physics Department, Faculty of Medicine, Mashhad University of Medical sciences, Mashhad, Iran
author
Hamid
Motahhari
Atomic and Molecular Physics Department, Yazd University, Yazd, Iran
author
Mahdi
Ghorbani
Biomedical Engineering and Medical Physics Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Recent developments of radiotherapy techniques, require high accuracy detectors to determine the delivered dose in a small area. Chemical vapor deposition (CVD) or naturally growth diamond detectors which are commercially available are good candidates for this purpose. In these detectors two electrodes with high different electrical potential are deposited on both sides of a diamond, and the incident radiation generates a current which indicates absorbed dose. However, the large band gap makes diamond an excellent electrical insulator, but care must be taken to eliminate the air ionization contribution to the photocurrent. For this reason, the device must operate in vacuum. In the other hand, patient’s safety needs a decrease in detector’s voltage. In this simulation study, it is indicated that the applied voltage can be decreased to about 50[V] without loss of dosimeter’s sensitivity.
Materials and methods: In this work Weightfield2 software, which is a program to simulate current signals in a silicon or diamond detector was used. This program uses GEANT4 libraries to simulate the energy released by an interacting particle. Minimum Ionizing Particle (MIP) with a 250 micrometers thick pure diamond was used and then the bias voltage was increased from 1 [V] to 500 [V], then the curve of time response and current response of the sensor was observed as a function of bias voltage.
Results: The results indicate that the applied voltage can reduce up to about 50 [V] with a reasonable 40 [ns] time response. This can be achieved by the benefit of high accuracy and fast Analog to Digital Converters (ADCs).
Conclusion: With new generation of synthetic diamonds known as single crystal CVDs, which their characteristic is very similar to natural diamond, and with modern electric measuring devices, in contrast to the current sensors, it is possible to reduce the applied voltage of dosimeter electrodes to about 50 [V].
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
330
330
https://ijmp.mums.ac.ir/article_12984_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12984
Evaluation of radiation protection principles observance in radiology departments of Semnan University of medical sciences
Elham
Kashian
MSc of Biomedical Engineering, Department of Biomedical Engineering, University of Medical Sciences, Kermanshah, Iran
author
Shiva
Zarifi
MSc of Medical physics, Department of Medical Physics, University of Medical Sciences, Semnan, Iran
author
Fatemeh
Akbarzadeh
MSc of Medical physics, Department of Medical Physics, University of Medical Sciences, Kermanshah, Iran
author
text
article
2018
eng
Introduction: Most of people are exposed to ionizing radiation sources during their lifetime including background, cosmic or man-made beams like radiation used in nuclear medicine and radiology. Due to unavoidable use of ionizing radiation in diagnosis and treatment of diseases, designing and correct implementation of radiation protection principles in order to reducing its harmful effects for radiation workers, patients and patient's companions is necessary. Therefore the aim of this study is to assess the staff's observance level of radiation protection principles in radiology departments.
Materials and MethodsIn this study, in order to evaluate the level of personnel awareness about the radiation protection principles and their observance as well as the protective equipment utility, a reliable and valid researcher-made checklist designed according to the radiation protection standards that have recommended by Atomic Energy Organization of Iran (AEOI) and then completed by personnel of radiology centers of semnan university of medical sciences. Acquired data were analyzed by SPSS software
.
Results: Based on the results, the awareness of personnel about protection standards was in the favorable level. The observance of the protection principles by the radiation workers of these centers was in accordance with recommended standards, the staff utilization level of radiation protection equipment is not acceptable. Generally the highest level of observance of protection measures was related to staff's protection and the lowest was for patient's companions
Conclusion; The results show that the observance level of protective principles in the studied departments has been acceptable. However, radiation protection training courses with emphasis on the use of radiation protection devices are recommended to raise awareness of personnel, observance level of protection principles and ultimately, to meet AEOI standards
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
331
331
https://ijmp.mums.ac.ir/article_12985_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12985
Determination of an Effective Wedge Angle by Combination of Two Arbitrary Universal Wedge Fields in Radiation Therapy of Cancer Patients with Megavoltage Photon Beams.
Azin
Shamsi
Department of Medical physics, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammad Javad
Tahmasebi Birgani
Department of Medical physics, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammad Ali
Behrooz
Department of Medical physics, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Shole
Arvandi
Department of Clinical Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Jafar
Fatahiasl
Department of Medical physics, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Reza
Maskny
Department of Medical physics, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Neda
Abdalvand
Department of Medical physics, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction: Wedge filters are commonly used in radiation oncology for eliminating hot spots and creating a uniform dose distribution in optimizing isodose curves in the target volume for clinical aspects. These are some limited standard physical wedges (15°, 30°, 45°, 60°), or creating an arbitrary wedge angle, like motorized wedge or dynamic wedge, ... The new formulation is presented by the combination of wedge fields for determining an arbitrary effective wedge angle. The isodose curves also are derived for these wedges.
Materials and Methods: we performed the dosimetry of Varian Clinac 2100C/D with Scanditronix Wellhofer water blue phantom, CU500E, OmniPro - Accept software and 0.13cc ionization chamber for 6Mv photon beam in depth of 10cm (reference depth) for universal physical wedges (15°, 30°, 45°, and 60°) and reference field 10x10cm2. By combining the isodose curve standard wedge fields with compatible weighting dose for each field, the effective isodose curve is calculated for any wedge angle.
Results: The relation between a given effective wedge angle and the weighting of each combining wedge fields was derived. A good agreement was found between the measured and calculated wedge angles and the maximum deviation did not exceed 3°. The difference between the measured and calculated data decreased when the combined wedge angles were closer. The results are in agreement with the motorized single wedge appliance in the literature.
Conclusion: This technique showed that the effective wedge angle that is obtained from this method is adequate for clinical applications and the motorized wedge formalism is a special case of this consideration.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
332
332
https://ijmp.mums.ac.ir/article_12986_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12986
Discrepancies in dose distributions due to age- dependent bone electron density in pediatric MRI-only treatment planning: A Monte Carlo study
Banafsheh
Zeinali-Rafsanjani
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mohammad Amin
Mosleh-Shirazi
Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Radiotherapy and Oncology Department, Shiraz University of Medical Sciences, Shiraz, Iran
author
Reza
Faghihi
Department of Medical Radiation Engineering, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
Radiation Research Center, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
author
Mahdi
Saeedi-Moghadam
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
Reza
Jalli
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction: MRI-only treatment planning (TP) can be advantageous in paediatric radiotherapy. However, electron density extraction is necessary for dose calculation. Normally, after bone segmentation, a bulk density is assigned. However, the variation of bone bulk density in patients makes the creation of pseudo CTs challenging. This study aims to assess the effects of bone density variations in children on radiation attenuation and dose calculation for MRI-only TP.
Materials and Methods: Bone contents of<15-year-old children were calculated, and substituted in the Oak Ridge National Laboratory paediatric phantoms. The percentage depth dose and beam profile of 150 kVp and 6 MV photon and 6 MeV electron beams were then calculated using Xcom, MCNPX (Monte Carlo N-particle version X) and ORLN phantoms.
Results: Using 150 kVp X-rays, the difference in attenuation coefficient was almost 5% between an 11-year-old child and a newborn, and ~8% between an adult and a newborn. With megavoltage radiation, the differences were smaller but still important. For an 18 MV photon beam, the difference of radiation attenuation between an 11-year-old child and a newborn was 4% and~7.4% between an adult and a newborn. For 6 MeV electrons, dose differences were observed up to the 2 cm depth. The percentage depth dose difference between 1 and 10-year-olds was 18.5%, and between 10 and 15-year-olds was 24%.
Conclusion: The results suggest that for MRI-only TP of photon- or electron-beam radiotherapy, the bone densities of each age group should be defined separately for accurate dose calculation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
333
333
https://ijmp.mums.ac.ir/article_12987_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12987
Comprehensive TLD dosimetry of physicians and patients during interventional angiography procedures to estimate the risk of radiation deterministic effect
Banafsheh
Zeinali-Rafsanjani
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
Mahdi
Saeedi-Moghadam
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
Fariba
Zarei
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Amin
Abolhasani Foroughi
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Reza
Faghihi
Department of Nuclear Engineering, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
author
Sepideh
Sefidbakht
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction: Interventional angiography procedures are increasingly used today. These techniques require a long time of standing near the patient and x-ray tube which lead to increase the radiation-dose of the staff and interventionists. This may also, in turn, lead to the occurrence of radiation deterministic effects. Since a large number of interventional radiology were performed in our center, it was necessary to monitor the radiation-dose of the interventionists and patients. This study intended to measure the patient dose and the radiation dose of the leg, hands and effective radiation-dose of the interventionist in order to determine whether they are under the dose limit or not.
Materials and Methods: To determine the radiation-dose of the interventionist’s leg an anthropomorphic phantom PBU-50 was used. Thermoluminescent-dosimeters (TLD-100) set on the leg of the phantom. The leg dose per each interventional procedures was calculated. In order to measure the dose of the hands and effective-dose the interventionists wear a ring containing three TLD chips and set two packs of TLD, one under the apron and one over the thyroid shield before the interventional procedures. The results of TLD readings were corrected for operational quantity HP (0.07) and HP (10) and using the Nilklason- algorithm, the effective-dose was calculated. To monitor the patient, dose the radiation dose, dose area product (dap) and radiation exposure time were recorded.
Results: The mean radiation-dose of leg per different procedures were 0.39mSv/Pro. The mean radiation-dose of hands per different procedures was between 19.79 to 34.90µSv/pro. The mean effective-dose provided by TLDs, and the annual dose of physicians resulted from these procedures were 30.38µSv, and 350.20µSv/y, respectively. The mean radiation-dose (mGy/min) and the mean dap (µGy.m2/min) of the patients per procedure were 57.27 and
546.89 respectively.
Conclusion: ICRP proposes that the annual dose limit of extremities should be < 500mSv to control the risk of temporary epilation and erythema. In this study, the radiation-dose of leg and hands were less than the dose limit. The annual dose to radiologists was less than the occupational dose limit. In most of the procedures, the patient dose was less than the erythema threshold dose. However, in one of the hepatic procedures (TIPS), the radiation- dose of the patient exceeds the threshold so that designing a plan to reduce the patient dose is necessary.
Although the interventional procedures are so time-consuming and deliver the most radiation-dose to the staff among the angiography procedures, if the protection devices were used properly the radiation-dose can be controlled under the dose limit value. In some limit procedures such as TIPS, the radiation-dose of the patients may exceed the threshold of deterministic effect of radiation so that some strategies should be considered to reduce their dose, such as limiting the time of the radiation exposure
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
334
334
https://ijmp.mums.ac.ir/article_12988_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12988
The effect of CT contrast agents on treatment planning and dose calculation in radiation therapy of pelvis cancers
Behzad
Changizi
Master of Medical Physics, Isfahan University of Medical Sciences, Isfahan, Iran. Tell: 0098-09363271261, Email:
author
Daryoush
Shahbazi
Professor of Medical Physics at Isfahan University of Medical Sciences, Isfahan, Iran. Tell:0098-091316786, Email: Shahbazi@med.mui.ac.ir
author
Mohammad Hasan
Larizadeh
Associated professor of Radiation – Oncology, Kerman University of Medical Sciences and Public Health, Tell: 0098-341-2115810, Email: larizad_mh@yahoo.com
author
text
article
2018
eng
Introduction: Using contrast medium in diagnosis and identifying of an organ from its surrounding tissue is very useful. These contrast mediums alter radiation absorption of studied organs. The aim of this study is to identify the influences of contrast media in treatment planning system of the pelvis.
Materials and Methods: Seven patients with pelvis area cancer with two sets of CT image, one with contrast medium and another without it, have been used and influences of contrast medium in treatment planning system for these patients were studied.
Results: After using contrast medium 2.63% increase in MU for RL field and 0.79%, 1.05%, 1.42% decrease in MU for AP, PA, RL fields have been obtained in rectum, respectively. For Bladder cancer, 0.34% decrease in MU of AP filed and 1.57%, 0.46%, 0.39% increase in MU for PA, RL and LL fields have been calculated, respectively. For cervix cancer, 1.1% decrease for AP field and 0.68% increase for PA field have been obtained.
Conclusion: According to the DVHs and calculated MUs, the results showed that the dose differences between the plans for the CT images with and without contrast medium were less than about 1% and was clinically tolerable.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
335
335
https://ijmp.mums.ac.ir/article_12989_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12989
Evaluation of dose distribution of 12C ion beam in radiotherapy by FLUKA as a Monte Carlo simulation Code
Jamshid
Soltani-Nabipour
Assistant professor, Department of Medical Radiation Engineering, Faculty of computer, Islamic Azad University, Parand Branch, Tehran-Iran
author
Danial
Malek hoseini
Department of medical radiation engineering, faculty of technical and engineering, Islamic azad university, Aliabad-e-katul branch, Golestan-Iran
author
Shabnam
Taleei
Department of physics, University of Mohaghegh Ardabili, Ardabil, Iran
author
text
article
2018
eng
Introduction: Nowadays, the use of heavy ion beams in cancer therapy have been developed worldwide.
Materials and Methods: It requires accurate understanding of the complex processes of ion interaction with matter, as it is the calculation the relative dose & range of these ions in matter. In the present study we used FLUKA as a numerical Monte Carlo simulations code for simulating the interaction of Carbon Ions beams of potential medical interest with water target as rough models for soft tissue.
Results: The depth dose deposition of Carbon ions beam with Energies of 135MeV/u and 195MeV/u in water were simulated and the results were compared with GEANT4 simulation code.
Conclusion: The results shows good agreement between FLUKA and GEANT4 and the Experimental data.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
336
336
https://ijmp.mums.ac.ir/article_12990_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12990
Prostate cancer radiomics: A study on IMRT response prediction based on MR image features and machine learning approaches
Hamid
Abdollahi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Isaac
Shiri
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
Biomedical and Health Informatics, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
author
Bahram
Mofid
Department of Radiation Oncology, Shohada Tajrish Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Abolfazl
Razzaghdoust
Urology and Nephrology Research Center, Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Afshin
Sadipour
Department of Radiation Oncology, Shohada Tajrish Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Seied Rabi
Mahdavi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
author
Mohsen
Bakhshandeh
Department of Radiology Technology, Allied Medicine Faculty, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: To develop different radiomic models based on radiomic features and machine learning methods to predict early intensity modulated radiation therapy (IMRT) response.
Materials and Methods: Thirty prostate patients were included. All patients underwent pre ad post-IMRT T2 weighted and apparent diffusing coefficient (ADC) magnetic resonance imaging (MRI). A wide range of radiomic features from different feature sets were extracted from all images. Delta radiomics was calculated as relative changes of pre-post-IMRT image features. Four feature selection methods and nine classification methods were evaluated in terms of their performance. We applied the 5-fold cross-validation as the criterion for feature selection and classification. For IMRT response prediction, pre, post and Delta radiomic features were analyzed. Area under the curve (AUC) was calculated as model performance value. IMRT response was obtained by changes in ADC values
.
Results: For IMRT response prediction, 15 models were developed. Pre-ADC model, unBalance/Select from Model/Adaptive Boosting had the highest predictive performance (AUC, 0.78).
Conclusion:Radiomic models developed by MR Image features and machine learning approaches are noninvasive, easy and cost effective methods for personalized prostate cancer diagnosis and therapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
337
337
https://ijmp.mums.ac.ir/article_12991_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12991
Evaluating the doismetric characteristics of some beta- emitter radionuclides for skin lesions irradiation
Azam
Afzalifar
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
author
Maryam
Bashi
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
author
Ali Asghar
Mowlavi
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
author
Hamid Reza
Baghani
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
author
text
article
2018
eng
Introduction: The dosimetric characteristics of patch sources including 32P, 90Y, 188Re and 166Ho, which are employed for radionuclide skin therapy, have been evaluated in current study
Materials and Methods: The patch sources understudy were modeled by MCNPX Monte Carlo code and corresponding depth dose distribution, transverse dose profile and isodose curves were calculated in a realistic model of skin phantom.
Results Calculated depth dose distributions had a good accordance with those reported by other measurement studies. Comparison of the calculated depth dose distributions for radionuclides understudy showed that the 166Ho and 32P have steeper dose gradient within the depth which can improve the sparing effect for underlying healthy tissues. Symmetric variations of calculated transverse dose profiles respect to the source central axis give a desirable dose uniformity within the target area for all studied patch sources. Obtained isodose curves showed that a circular area with the diameter of around 8 mm can cover the 90% isodose for all studied beta sources.
Conclusion: Based on the obtained results, it can be concluded that the 166Ho and 32P have more desirable dosimetric characteristics for irradiating the superficial skin lesions. On the other hand, irradiation of deep skin tumors through 90Y and 188Re sources will improve the treatment quality viewpoint to the better coverage of target area. Size of employed patch source should be should be selected in such a way that the delivered dose to the adjacent tissues would be minimized.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
338
338
https://ijmp.mums.ac.ir/article_12992_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12992
Radiomics modelling of IMRT induced acute rectal toxicity using clinical and magnetic resonance imaging features
Hamid
Abdollahi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
Shayan
Mostafaei
Department of Community Medicine, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Epidemiology and Biostatistics Unit, Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
author
Bahram
Mofid
Department of Radiation Oncology, Shohada Tajrish Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Abolfazl
Razzaghdoust
Urology and Nephrology Research Center, Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Afshin
Sadipour
Department of Radiation Oncology, Shohada Tajrish Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Seied Rabi
Mahdavi
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
author
Mohsen
Bakhshandeh
Department of Radiology Technology, Allied Medicine Faculty, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Rectal toxicity is a dose limiting issue in prostate cancer radiotherapy. Prediction of these effects may be used to tailor the therapy. The purpose of this work was to develop predictive radiomic models based on clinical, dosimetric and radiomic features extracted from rectal wall magnetic resonance image (MRI).
Materials and Methods: This study was conducted on 30 prostate cancer patients underwent intensity modulated radiation therapy (IMRT). Patient’s clinical and dosimetric parameters were collected and proctitis was assessed. All patients underwent MRI before and after IMRT with same protocol. Several radiomic features were extracted from rectal wall MR images including T2 weighted (T2W) and apparent diffusion coefficient (ADC) scans and robust features were found. Lasso regularization was used to create multivariable Elastic Net logistic regression model, based on clinical, dosimetric and robust features for prediction and feature selection, simultaneously. All models were cross-validated using repeated five-fold cross-validation and their performance were evaluated by area under the curve of the ROC curve (AUC), sensitivity and specificity.
Results: Eleven predictive models including one clinical and ten radiomic models were built. All models were found as high predictive performance (AUC≥0.83). T2 based radiomic models were more predictive rather than ADC models. Post-IMRT T2W radiomic model also showed a good predictive performance. Image features enhanced the all model’s predictive performance.
Conclusion: Rectal wall MR radiomic features integrating with clinical and dose-volume parameters could improve the prediction performance of radiotherapy induced proctitis. The authors have demonstrated the performance of radiomic features extracted from pre IMRT T2W and ADC MR Images for prediction of IMRT induced rectal toxicity. These results may be used to tailor the therapy in terms of patient and.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
340
340
https://ijmp.mums.ac.ir/article_12993_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12993
Investigate Change Cardiac Perfusion Pattern Following By Hypo-fractionated and Conventional Radiation Therapy Schedule in Patients with Left-Sided Breast Cancer
Dariush
Askari
Assistant Professor, Department of Radiology Technology, Faculty of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Darband St, Ghods Sq., Tehran, Iran.
author
Mohsen
Bakhshandeh
Assistant Professor, Department of Radiology Technology, Faculty of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Darband St, Ghods Sq., Tehran, Iran. Phone: +98-21-22717503, Fax: +98-21-22717503, E-mail: mbakhshandeh@sbmu.ac.ir
author
Mahasti
Amoui
Department of Nuclear Medicine, Shohada-e Tajrish Hospital, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Hamidreza
Mirzaee
Cancer Research Center, Shohada-e Tajrish Hospital, Department of Radiation Oncology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mona
Malekzadeh
Cancer Research Center, Shohada-e Tajrish Hospital, Department of Radiation Oncology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Radiation-induced cardiovascular damage is a potential side effect of radiation therapy in patients with left-sided breast cancer. This prospective study compares the severity and reversibility of perfusion and functional abnormalities before, and six months after, 3D-Conformal radiation therapy treatment in left-side breast cancer patients with conventional and hypofractionated schedule radiation therapy by stress/rest gated myocardial perfusion imaging.
Materials and Methods: Stress/rest gated myocardial perfusion imaging with Tc-99m MIBI was performed in 36 patients with left-sided breast cancer before, and six months after, completion of radiation therapy schedules.
Results: Myocardial perfusion defects were detected in 82.6% and 76.90% of patients with conventional and hypofractionated radiation therapy schedule, which were prominently located in anteroseptal (60.9% vs. 69.2%), anterior (52.2% vs. 61.5%), anterolateral (47.8%
vs. 23.1%), apex (34.8% vs. 38.5%), lateral (21.7% vs. 7.7%) and inferior (8.7%Vs 0.0%) walls, respectively. Frequency of mild, moderate and severe perfusion defects in the radiation therapy schedules were 39.1% vs. 15.4%, 21.7% vs. 38.5% and 21.7% vs. 23.1%, respectively. Myocardial perfusion defects were reversible, partial reversible or fixed in 26.09% vs. 30.8%, 34.78% vs. 30.8% and 21.74% vs. 15.04% patients, respectively. A statistically significant increase was found in the summed stress score, summed difference score and summed rest score of patients treated with conventional and hypofractionated radiation therapy schedule at six months after treatment, compared to the baseline study. Also, between the dosimetric parameters and semi-quantitative SPECT data of patients, a significant correlation was observed.
Conclusion: Radiation-induced cardiovascular damage is a common finding six months after radiation therapy. Cardiac complications show no statistically significant differences between the two radiation therapy schedules. Both stress and resting gated MPI are required for assessment of changes in myocardial perfusion in patients with left-sided BC
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
341
341
https://ijmp.mums.ac.ir/article_12994_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12994
Comparison of two radiation techniques in breast boost delivery
Tayyeb
Pourfallah
Department of Biochemistry and Biophysics, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
author
Danial
Seifi Makrani
Department of Biochemistry and Biophysics, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
author
text
article
2018
eng
Introduction: In the treatment of breast cancer, breast conserving surgery (BCS) and whole breast irradiation is a usual technique. The influence of lumpectomy boost following breast radiotherapy is apparent, but there are different delivery methods. This work intended to compare the dosimetric parameters of electron beams and photon beams for boosting irradiation in breast cancer patients who experienced breast-conserving surgery and whole- breast irradiation.
Materials and Methods: In this study we compared plans for electron beams and photon beams boost irradiation for 32 breast cancer patients who experienced breast-conserving surgery. Each patient was firstly treated by whole breast irradiation (45 Gy in 25 fractions) and then followed by lumpectomy boost (10 Gy in 5 fractions) with either electron beam therapy or with photon, 16 patients in each group. The organs at risk (OAR) involved the coronary arteries, lungs, and skin. For dosimetric comparison, conformity index (CI), homogeneity index (HI), uniformity index (UI) and dose-volume parameters for the planning target volume (PTV), and OAR were studied.
Results: From 2015 to 2017, thirty-two (32) patients enrolled the study. There were 11 patients (35%) with stage IIA, 14 patients (44%) with stage IIB and 7 patients (21%) with stage IIIA. Median age was 52 years (range 42-73). In the case of CI and HI significant differences were found in approval of the photon boost but in the evaluation of UI no major difference was noticed between two techniques. For PTV coverage of V95% and V107% the photon plans was superior to that of electron plans. About OAR sparing, the photon beam reduced the high-dose volume with cost of an increased low-dose volume. The high-dose volumes increased with electron plans.
Conclusion: Data show that photon boost irradiation provides better coverage to the tumor bed and improved dosimetric parameters compared to electron boost, considered the fact that PTV coverage and OAR sparing were superior with photons. It can be conclude that in centers where electron beam therapy is not presented, photon beam can be used efficiently for lumpectomy boost
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
342
342
https://ijmp.mums.ac.ir/article_12995_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12995
Evaluation of CorePlanTM treatment planning system for 6 and 15 MV photon irradiation
Danial
Seifi Makrani
Department of Biochemistry and Biophysics, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
author
Tayyeb
Pourfallah
Department of Biochemistry and Biophysics, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
author
text
article
2018
eng
Introduction: Radiotherapy is an effective modality to treat esophageal carcinoma. Due to various inhomogenous tissues with a variety of physical and radiological properties which can cause uncertainty in accurate dose calculations in radiation therapy, accuracy of TPS is very important. The aim of this study was to quantify dose calculation accuracy of CoreplanTM TPS in an inhomogenous home-made phantom.
Materials and Methods: Thermoluminescent dosimeter-100 (TLD-100) chips were used within inhomogeneous home-made phantom for dose measurement; CoreplanTM was also applied for dose calculation. Finally, difference between measured doses and calculated doses was gotten to calculate dosimetry accuracy of the TPS at PTV and neighbor’s organ at risks region.
Results: Findings indicated that for regions near PTV, Coreplan TPS leads to an overdose estimation up to 2.3% and 4.8% for the 6 and 15 MV energies, respectively and in regions far from primary field, the Coreplan TPS underestimated the dose compared to the measurements which might be due to scattered radiation that is not well considered in the TPS.
Conclusion: Due to the inhomogeneous in the thorax region, the dose calculation accuracy of TPS should be appropriate. The agreement criterion was determined according to ICRU recommendation, which suggest the accuracy of ±5% in the delivery of an absorbed dose to a target volume. According to the results, it is concluded that the accuracy of dose calculation of Coreplan TPS showed good agreement with experimental data.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
343
343
https://ijmp.mums.ac.ir/article_12996_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12996
Comparison of radiotherapy techniques to reduce hematologic toxicity in whole pelvic radiation therapy
Tayyeb
Pourfallah
Associated Professor, Department of Biochemistry, Biophysics and Genetic, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. Mailing Address: Payambar Azam (PBUH) Academic Complex, 18km of Khazar-abad Road, Sari, Iran.
author
Danial
Seifi Makrani
Department of Biochemistry, Biophysics and Genetic, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
author
text
article
2018
eng
Introduction: Concurrent chemoradiotherapy (CRT) is a standard treatment method for patients with carcinoma of cervix. Despite admirable therapeutic results, acute hematologic toxicity (HT) is common with this regimen. Many studies evaluate the relationship between the bone marrow dosimetric parameters and the severity of HT and result shown that the low dose of bone marrow would decrease the incidence of HT in patient undergoing concomitant CRT. In this study the dosimetric parameters of two radiotherapy plans in managing of cervix cancer has been evaluated to investigate the best plan on the way of reducing bone marrow dose.
Materials and Methods: Computed tomography scans of 18 patients with carcinoma of cervix were acquired and transferred to the 3D treatment planning system. The corePlan3D treatment planning system was used to contour all of the structures and to compute the dose distribution for plans based on collapsed cone convolution (CCC). For each patient, two different treatment plan were prepared using 15 MV photon energies. The minimum dose (Dmin), maximum dose (Dmax) and mean dose (Dmean) to target (PTV) and femoral head were compared for each plan.
Results: Result shown that our manipulated four-field plan which use anterior oblique beams seemed to deliver a lower mean dose to femoral head against conventional box fields (Dmean=66.7±3.1 cGy, 98.8±7.3 cGy, Dmax=117.5±3.0 cGy, 126.9±4.3 cGy, respectively) and deliver sufficient dose to PTV (Dmax=213.5±4.2 cGy, 194.6±2.0 cGy, respectively).
Conclusion: With suspicious planning in respect to choice of beam angles, beam weighting, and appreciation of potential exposure of normal tissues to exit dose, this study revealed that compared with conventional box fields, anterior oblique beams can achieve significant reductions in the dose to BM with adequate dose coverage to the PTV with an accurate beam arrangement
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
344
344
https://ijmp.mums.ac.ir/article_12997_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12997
Microdosimetry: experimental methods and medical applications
Nahideh
Gharehaghaji
Radiology Department, Paramedical Faculty, Tabriz University of Medical Sciences, Tabriz, Iran
author
Davood
Khezerloo
Radiology Department, Paramedical Faculty, Tabriz University of Medical Sciences, Tabriz, Iran
author
text
article
2018
eng
Introduction: Microdosimetry is a fundamental method that studies the nature of energy transfer in micron volumes in the particular biological cells. In a biological target, the amount of ionization does not indicate the magnitude of biological radiation-induced damage. However, the severity of biological harm depends strongly on the amount of the linear energy transfer along the direct path of the ionization particle, LET. Generally, the main objective of the microdosimetry is to measure the two fundamental parameters including lineal energy transfer (y) and specific energy (z).
Materials and Methods: By scientific search engines Pubmed, Scopus, Elsevier the keywords "Microdosimetry", "Lineal energy transfer", "Specific energy" were searched and extraction data were analyzed qualitatively.
Results: Experimental methods in microdosimetry are based on the theory of Bragg-Gray cavity. The low-pressure gaseous proportional counter is the main tool in the microdosimetry. The material and thickness of the counter wall should be such that it generates “Charge Particle Equilibrium”. The standard plastics formulation of the wall which was introduced by Shonka is a combination of calcium fluoride, polyethylene, nylon and carbon. The most common gases for sensitive volume of counter are based on the composition of methane and propane. Other experimental methods in microdosimetry are: Autoradiography technique, Wilson cloud chamber, micro strip gas counter (MSGC) and gas electron multiplier (GME) technique with sensitive volume of less than 1mm3 and optical ionization chamber.
Conclusion: Microdosimetry has applications in radiation protection, radiobiology and radiotherapy. The biological effect of the radiation depends on the weight factor of the beam, which is obtained by multiplying it in the absorbed dose by the equivalent dose amount. In radiobiology, the RBE ratio is more accurately obtained by microdosimetry. In high LET radiation, the differences between LET and RBE is not negligible; therefore, in the new techniques of radiation therapy with high LET radiation such as neutron and heavy particles, microdisimetry can accurately measure dose.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
345
345
https://ijmp.mums.ac.ir/article_12998_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12998
Determination of therapeutic standard field for cancer patients including the medical megavoltage accelerator jaws movement.
Mohammad Javad
Tahmasebi Birgani
Professor of Radiotherapy and Oncology, Department of Radiotherapy and Oncology, Golestan Hospital, Ahvaz Jndishapur University of Medical Sciences, Ahvaz, Iran.
author
Nahid
Chegeni
Assistant Professor of Medical Physics. Department of Medical Physics, Medical School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Raziye
Fayazi
Msc students of medical physics, Department of Medical Physics, Medical School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Marziyeh
Tahmasbi
Assistant Professor of Medical Physics. Department of Radiology Technology, Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Jafar
Fatahi Asl
Assistant Professor of Medical Physics. Department of Radiology Technology, Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammad.Ali
Behrooz
Professor of Radiotherapy and Oncology, Department of Radiotherapy and Oncology, Golestan Hospital, Ahvaz Jndishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction: Accurate calculation of equal square field size is important in radiation therapy and A factor, in the Vadash formula must be determine by considering collimator exchange effect. Therefore, the purpose of this study was to determine the best A factor, for calculation of equal square field size in treatment planning
Materials and Methods: A new simple protocol method based on the selection of best dosimetric data was proposed to obtain A value in Vadash relation to predict the equivalent square field size, which compensates collimator exchange effect in output factors in air (OFair). Measurements performed with Farmer chamber 0.6 cc in SSD 100cm and build up cap of Plexiglas, 1.5 and 3.5 cm equals water, for 6 and 18 MV, respectively on a Perimus Plus linear accelerator. OFair measured for square and rectangular fields. MATLAB software (version R2014a) was used to calculations and curve fitting.
Results: Power model with constant value applied to OFair as a function of square field size. OFair ranged from 0.983 to 1.038 in 6MV and from 0.731 to 1.05 in 18 MV and Y collimator had a greater effect on the OFair. The values of 1.42 and 1.55 were selected for "A" in 6 and 18 MV, respectively.
Conclusion: The proposed A values minimize the collimator exchange effect, in calculating the equivalent squares which plays an important role in the patient dose calculation and treatment planning. The value of A should be calculated for each machine and energy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
346
346
https://ijmp.mums.ac.ir/article_12999_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.12999
Histogram analysis- a useful tool for tissue characterization in brain CT
Fariba
Zarei
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
Asiyeh
khoshandish
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
S.
Chatterjee
Ongil, 79 D3, Sivaya Nagar, Reddiyur Alagapuram, Salem 636004. India
author
Vani
VC
Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012, India Professor
author
Rezvan
Ravanfar Haghighi
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
text
article
2018
eng
Introduction: Pixel value in computed tomography (CT) gives the average linear attenuation coefficient of the scanned material in the path of the x-ray beam, being normalized to that of water. It is known that attenuation coefficient or HU value is a function of the chemical characteristic of the material and of the x-ray energy. The CT image shows the HU value by a shade of gray in each pixel. Human eye is often not able to discriminate gray shadows; whose grayness are close to each other. Therefore, when two different tissues have very similar chemical characteristics they may not be distinguishable in the CT image by human eyes. For this reason, in CT image, it is difficult to distinguish between brain tumor and ischemia, in the hypodense area. The aim of this study is to use histogram analysis, based on the frequency distribution of the HU values in brain CT images to evaluate the possibility of distinguishing tumor from ischemia.
Materials and Methods: We collected 150 axial slices of brain CT, from known hypodense areas belonging to ischemia and tumor with similar appearance. They contained 75 samples of each type. Minimum, maximum, and mean HU values of ROI inside the lesions were used to make the histogram, cumulative and probability percentage distribution. We used 10 unknown cases, 5 tumors and 5 ischemia, to evaluate our finding.
Results: Bar chart and linear diagram histogram show that the minimum, maximum and mean of HU values are higher in ischemia cases. Also, the median of the cumulative distributions of minimum, maximum and mean appear at higher HU values for ischemia. The probability of occurrence of ischemia cases increases with increasing HU values of minimum, maximum and mean while the behavior of the tumor cases is completely reverse. We have done the same data analysis for 10 unknown cases. Our predictions match in 80% of the cases, with the radiologist’s conclusion, who were unaware of our findings.
Conclusion: Histogram analysis may be used as an effective tissue characterization tool in non-enhanced brain CT images. This method could distinguish hypodense areas of ischemic lesion from tumor, as is seen, for the first time, in the present study.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
347
347
https://ijmp.mums.ac.ir/article_13000_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.13000
An iterative method to estimate x-ray attenuation coefficients in computed tomography
Rezvan
Ravanfar Haghighi
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
Somayeh
Gholami Bardeji
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
Mahdi
Dodangeh
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
S.
Chatterjee
Ongil, 79 D3, Sivaya Nagar, Reddiyur Alagapuram, Salem 636004, India
author
Ali Reza
Shakibafard
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
Reza
Jalli
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
Sepideh
Sefidbkht
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
Fariba
Zarei
Medical imaging Research Centre, Shiraz University of Medical Sciences, Shiraz 7193635899, Iran
author
Vani
VC
Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012. India
author
text
article
2018
eng
Introduction: The basis of image formation in Computed Tomography (CT) lies in the x-ray linear attenuation coefficient of the scanned material. Compton scattering and photoelectric effect are the dominant interactions of the x-ray photons with the subject, in the range of diagnostic radiology. These two coefficients are important in tissue characterization by Dual-Energy CT (DECT), determination of electron density and dose calculation in treatment planning system. The aim of this paper is to calibrate the CT system, to calculate Compton scattering and photoelectric effect by an iterative method.
Materials and Methods: Chemical compounds with known effective atomic number and electron density were scanned at 80, 110, and 130kVp. HU values of these compounds were used to calculate Compton scattering and photoelectric effect by an iterative method. The calculated coefficients were used to estimate the HU values of liquid samples and solid rods made of polymers, to evaluate our findings
Results: The coefficients were found up to the fifth order of iteration and the coefficients were found to match the data with 95% confidence at 80, 110, and 130 kVp. The maximum deviation between the calculated and actual HU values were less than 3% for liquid and solid samples at these kVp values.
Conclusion: Calibration of CT system by known chemical samples, by using iterative method of data analysis may give very accurate idea about the x-ray attenuation coefficients of samples. Results of this study may be used in tissue characterization by DECT inversion, and to estimate electron density and dose distribution in treatment planning systems
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
348
348
https://ijmp.mums.ac.ir/article_13001_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2019.13001
The role of dose fractionation in the level of Radiation- Induced Bystander Effect in QU-DB Cells
Roghayeh
Kamran Samani
Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Shokouhozaman
Soleymanifard
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mohammad Taghi
Bahreyni Toossi
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Shokoufeh
Mohebbi
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
text
article
2018
eng
Introduction: Radiation effects induced in non-irradiated cells are termed radiation- induced bystander effects (RIBE). The present study intends to examine the RIBE response of QU-DB bystander cells to first, second and third radiation fractions and compare their cumulative outcome with an equal, single acute dose.
Materials and Methods: This experimental study irradiated three groups of target cells for one, two and three times with 60Co gamma rays. One hour after final irradiation, we transferred their culture media to non-irradiated (bystander) cells. We used the cytokinesis block micronucleus assay to evaluate RIBE response in the bystander cells. The numbers of micronuclei generated in bystander cells were determined.
Results: RIBE response to single acute doses increased up to 4 Gy, then decreased, and finally at the 8 Gy dose disappeared. The second and third fractions induced RIBE in bystander cells, except when RIBE reached to the maximum level at the first fraction. We split the 4 Gy acute dose into two fractions, which decreased the RIBE response. However, fractionation of 6 Gy (into two fractions of 3 Gy or three fractions of 2 Gy) had no effect on RIBE response. When we split the 8 Gy acute dose into two fractions we observed RIBE, which had disappeared following the single 8 Gy dose.
Conclusion: The impact of dose fractionation on RIBE induced in QU-DB cells depended on the RIBE dose-response relationship. Where RIBE increased proportionally with the dose, fractionation reduced the RIBE response. In contrast, at high doses where RIBE decreased proportionally with the dose, fractionation either did not change RIBE (at 6 Gy) or increased it (at 8 Gy).
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
349
349
https://ijmp.mums.ac.ir/article_13002_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13002
Determination of internal absorbed dose from radiation of 111In-Rituximab in body
Zahra
Mohamad Darvishi
MSc Student, Department of Physic, Eslamic Azad University, Tehran, Iran. Author’s
author
Seyed Pezhman
Shirmardi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran, P_shirmardi@aut.ac.ir
author
text
article
2018
eng
Introduction: There are many ways to treat cancer and pain relief. One of the methods is radiopharmaceutical therapy. Indium 111-rituximab contains the radioisotope indium-111 and rituximab. The Indium-111, after decay, emits gamma rays with energies of 245 KeV and 171 KeV, and beta-radiation of 26 KeV. In this study, the absorbed dose of 111In-Rituximab in human body was calculated using mice data and MCNPX simulation code for the organs of heart, lung, liver, spleen, kidney, stomach, intestine and pancreas.
Materials and Methods: Male phantom was used for this simulation. The source and target organs were defined in code and absorbed dose obtained for per particle with error of 5 percent. The source organs were determined as volume source in SDEF card of MCNP code. Simulations were done in two steps for gamma and beta sources and the final absorbed dose of each organ were multiplied by the amount of cumulated activity of 1MBq.
Results: The results showed that the absorbed dose due to injection of 111In-Rituximab for organs of spleen and stomach are 2.2252E-02, 5.5979E-03 respectively. so these organs are at risk in treating cancer with this radionuclide. The errors for were less than 5 percent.
Conclusion: Monte Carlo method and MCNPX simulation code are important methods for calculation of the absorbed dose after the distribution of rradionuclides in the body. Also the results show that two organs spleen and stomach are at risk in Indium 111-rituximab therapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
350
350
https://ijmp.mums.ac.ir/article_13003_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13003
The effect of gold nanoparticles on dose enhancement factor of human intestinal colon cancer HT-29 cells
Zohre
Rezaee
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Ali
Yadollahpour
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Vahid
Bayati
Cellular and Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammad Javad
Tahmasebi Birgani
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction: Radiation therapy is an important procedure for treatment of more than half of tumors. One way to increase the efficiency of radiation therapy is application of radiosensitizer at the site of tumor. gold nanoparticles (GNPs) have several characteristics that make them attractive for using with radiation therapy including small size (1–100 nm), biocompatibility, preferentially passive accumulation in tumor and the feasibility to surface modification to actively target cancerous cells. The aim of this paper was investigating the radiosensitizing effect of GNPs in human intestinal colon cancer HT-29 cells as a less radiosensitive tumor cell.
Materials and Methods: Radiosensitizing effects of GNPs were comparatively evaluated in vitro for intestinal colon cancer (HT-29) cell line by colony formation assay at 6 MV photon energy. Cells were treated with only ionizing irradiation (IR) as control group or combination of GNPs and ionizing irradiation (GNPs+IR). GNPs had average size of 15 nm and were used at concentration of 0.1 mM.
Results: The survival curve was obtained using MATLAB software and dose enhancement factor (DEF) was calculated by dividing of LD50 (50% lethal dose) of IR group with combination treatment group (GNPs+IR). GNPs could enhance treatment response by factor of 1.47(DEF=1.47).
Conclusion: Our results showed that GNPs can sensitize HT-29 tumor cells and thus can be used to enhance the radiation therapy efficiency.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
351
351
https://ijmp.mums.ac.ir/article_13004_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13004
Investigating the synergistic effects of gold nanoparticles and electroporation in sensitization of human intestinal colon cancer HT-29 cells to 6MV photon beam
Zohre
Rezaee
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Ali
Yadollahpour
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Vahid
Bayati
Cellular and Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammad Javad
Tahmasebi Birgani
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction: Radiation therapy (RT) is the gold standard treatment for more than half of known tumors. There is increasing evidence that combining radiation therapy with a radiosensitizer can enhance the efficiency of this treatment modality. A radiosensitizer preferably enhances dose at the site of tumor and increases discrimination between tumor and normal surrounding tissues. Gold nanoparticles (GNPs) and electroporation (EP) have shown good potential as radiosensitizers. Therefore, the present study assessed the sensitizing effects of EP, GNPs, and combined EP-GNPs on the dose enhancement factor(DEF) for 6 MV photon energy.
Materials and Methods: In this in-vitro study, intestinal colon cancer (HT-29) cells treated with four different protocols: ionizing radiation alone (IR, control group), EP+IR, GNPs+IR and GNPs+EP+IR. Radiosensitization was assessed by colony formation assay at 6 MV photon energy. The survival curve was estimated using MATLAB software and DEF for each combination treatment group was calculated by dividing of LD50 (50% lethal dose) of control group with combination treatment group.
Results: when the cells were treated with EP prior to IR the DEF of 1.36 was achieved. Treatment of cells with GNPs immediately before irradiation resulted in DEF of 1.17. In this group, GNPs did not significantly enhance the effect of IR due to having not enough time for GNPs to enter and accumulate in the target cells. However, when EP was added to the protocol of GNPs+IR group, DEF of 2.61 was observed. The observed difference between DEF values of GNPs+IR and GNPs+EP+IR groups can be attributed to the act of EP as a GNPs delivery system in GNPs+EP+IR group.
Conclusion: Combined GNPs-EP protocol could induce synergistic effects in HT-29 cells and it can be beneficially used for the treatment of intrinsically less radiosensitive tumors.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
352
352
https://ijmp.mums.ac.ir/article_13005_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13005
Measurement of Entrance Skin Dose and Effective Dose in The most Common Diagnostic radiology Examinations in Jiroft, Iran
Foad
Goli Ahmadabad
School of Medicine, Jiroft Universitu of Medical Sciences, Jiroft, Iran
author
Zeinab
Momeni
Medical Physics Department, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Salar
bijari
Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Amin
Banaei
Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
author
Susan
Ebam
Department of environmental Health engineering, Jiroft university of Medical Sciences, Jiroft, Iran.
author
text
article
2018
eng
Introduction: Medical uses of radiation have grown very rapidly over in the past two decades, medical uses represent the largest source of exposure to people, The most important methods in medical diagnosis are the useses of diagnostic radiology exams. Although the use of these methods is very beneficial for the treatment of patients, but ionizing radiation produces ion pairs, radicals, primary, secondary, and tertiary chemical reactions in body. The main purposes of this study were to investigate patient dose in common radiographic examinations
Materials and Methods: This study was performed in radiology centers and hospitals affiliated with Jiroft University of Medical Sciences, including Qaleh Ganj Hospital, Imam Khomeini Hospital, Kashani Hospital and 12th Farvardin Kahnoch Hospital. In each center, measurements are performed on at least 10 patients aged between 25 - 60 years for different imaging techniques including: Chest (PA), Pelvic (AP), Abdomen (AP), Skull (AP) and (LAT), Lumbar Spine (AP) and, Lumbar Spine (LAT) .ESD, ED were measured with T-LD 100 and PCXMC software, respectively
Results: The average entrance skin dose (mGy) and effective dose (mSv) for the Chest (PA), Abdomen (AP), Pelvice (AP), Lumbar Spine (AP) and Lumbar Spine (LAT) and Skull (AP) and Skull (LAT) were (0.63-0.06), (2.34-0.32), (2.48-0.39), (3.33-0.34), (7.32-0.17), (2.9-0.02)
and (1.81-0.01) respectively.
Conclusion: The values indicate that the implementation of quality control and quality assurance programs in the radiology centers is necessary and all radiographic exams should be performed under lower doses with best quality of image.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
353
353
https://ijmp.mums.ac.ir/article_13006_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13006
Evaluation of effect of gold nanorods and spherical gold nanoparticles of different sizes on X-ray attenuation in computed tomography
Sara
Khademi
Department of Radiology Technology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
author
Hossein
Ghadiri
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
Saeed
Sarkar
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
Sharmin
Kharrazi
Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
Seyed Mohammad
Amini
Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
author
Ali
Shakeri-Zadeh
Medical Physics Department, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
Mohammad Reza
Ay
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: To date, gold nanoparticles (GNPs) have been demonstrated to have great potential as contrast agent for CT imaging and therapeutics. This study was designed to evaluate any effect on X-ray attenuation that might result from using GNPs with a variety of size, surface chemistries and shapes.
Materials and Methods: Spherical GNPs and gold nanorods (GNRs) were synthesized for CT imaging application. X-ray attenuation was quantified by Hounsfield unit (HU) in CT. Transmission electron microscopy (TEM) was performed to investigate morphology and size of the GNPs. The concentrations of GNPs in μg/ml were measured by the inductively coupled plasma optical emission spectrometry (ICP-OES). Chemical component was also determined by a Raman Spectrometer.
Results: Our results indicated that smaller spherical GNPs (13 nm) had higher X-ray attenuation than larger ones (60 nm) and GNRs with larger aspect ratio exhibited great effect on X-ray attenuation. Moreover, poly ethylene glycol (PEG) coating on GNRs declined X-ray attenuation as a result of limiting the aggregation of GNRs. Overall, smaller spherical GNPs can be suggested as a better alternative to conventional contrast agent (ie; Omnipaque) , for CT imaging.
Conclusion: The X-ray attenuation and the ease of the surface functionalization, make GNPs promising multifunctional probes for simultaneous imaging and drug or gene delivery applications. Size, morphology, concentration and surface of GNPs can effect on X-ray attenuation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
354
354
https://ijmp.mums.ac.ir/article_13007_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13007
Evaluation of multifunctional targeted gold nanoparticles on X-ray attenuation in nasopharyngeal cancer cells by X- ray imaging
Sara
Khademi
Department of Radiology Technology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
author
Hossein
Ghadiri
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Science, Tehran, Iran
author
Saeed
Sarkar
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Science, Tehran, Iran
author
Ali
Shakerizadeh
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
author
Neda
Attaran
Department of Medical Nanotechnology, Applied Biophotonics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Sharmin
Kharrazi
Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
author
Mohammad Reza
Ay
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Science, Tehran, Iran
author
text
article
2018
eng
Introduction: Head-and-neck cancer is the sixth most common cancer worldwide with the number of cases consistently increasing in developing countries. Successful development of effective, safe and cost effective nanoprobes for head-and-neck cancer targeting imaging is a big challenge. This study is aimed to develop cysteamine-folate conjugated gold nanoparticles (F-Cys-AuNPs) as a new contrast agent for targeted X-ray computed tomography imaging (CT) of head-and-neck cancer cells. In the other hand, this study is aimed to evaluation of effect of incubation times of multifunctional nanoparticles on cancer cells by CT.
Materials and Methods: The formed multifunctional F-Cys-AuNPs were characterized via different techniques. Transmission electron microscopy (TEM) was performed to investigate morphology and size of the GNPs. The concentrations of GNPs in μg/ml were measured by the inductively coupled plasma optical emission spectrometry (ICP-OES). The cytocompatibility of the F-Cys-AuNPs were assessed by MTT and colony assays. Targeted ability of F-Cys-AuNPs was evaluated in head-and-neck cancer in different incubation times.
Results: F-Cys-AuNPs nanoprobes with an Au core size of ~15 nm exhibited good biocompatibility, and could target actively the cancer cells. Our results indicated that a greater mass concentration in all the nanoparticles and increasing incubation times lead to greater X-ray attenuation and totally in clinic lead to payload the delivery of a larger mass in the site of interest, therefore, the contrast will be enhanced.
Conclusion: This data can be also considered for the application of gold nanostructures in radiation dose enhancement where nanoparticles with high X-ray attenuation are applied. The X-ray attenuation and the ease of the surface functionalization, make targeted GNPs promising multifunctional probes for simultaneous imaging and drug or gene delivery applications.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
355
355
https://ijmp.mums.ac.ir/article_13008_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13008
Evaluation putty metal as internal shield for patient protection of electron therapy by Monte Carlo study
Mohammad javad
Tahmasebi Birgani
Professor, Department of Medical Physics, School of Medicine; Department of Radiotherapy and Radiation Oncology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz,Iran,Tahmasebi_MJ@yahoo.com
author
Mansour
Zabihzadeh
Assistant professor, Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz,Iran, zabihzadeh@ajums.ac.ir
author
Saeideh
Aliakbari
Ph. D Candidate , Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz,Iran, aliakbarisaeedeh@gmail.com
author
Mohammad Ali
Behrouz
Professor, Department of Medical Physics, School of Medicine; Ahvaz Jundishapur University of Medical Sciences, Ahvaz,Iran, mabehrooz@yahoo.com
author
Seyyed Mohammad
Hosseini
Assistant Professor, Department of Radiation Therapy, University of JundiShapoor, Golestan Hospital, Ahvaz, Iran, kiahossainy@yahoo.com
author
text
article
2018
eng
Introduction: In this study, a specific combination (70% W 18.61% Ni and 11.39% C) of lead free and flexible putty metal is introduced and validated as internal shielding by Mont Carlo study
Materials and Methods: To evaluate putty metal as an internal shielding by Mont Carlo study Varian 2100 C/D was validated within measurement and then by given energy spectrum of Varian 2100 C/D shield thickness and backscatter factor were obtained by Mont Carlo study and compared to those of lead.
Results: The results showed that this putty metal shield required comparable thickness for providing protection compared to lead. In addition, it is nontoxic and flexible in that it can be easily cut. Internal shielding with high atomic number causes dose enhancement that isn’t taken into account in treatment planning system. This study showed that this composition as internal shield causes 5-7% reduction of electron backscatter factor relative Lead.
Conclusion: it can be concluded that lead can be replaced by putty metal with specific combination (70% W, 18.61% Ni and 11.39% C). It is Lead free, flexible and thickness required for protecting tissue is acceptable under clinical condition and it causes 5 -7% reduction of electron backscattering
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
356
356
https://ijmp.mums.ac.ir/article_13020_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13020
Radiolabeling the Peptides extracted from Scorpion venom (ICD-85) with 99mTc as treatment and imaging agent for cancer
Seyed Pezhman
Shirmardi
Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
Mostafa
Erfani
Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
Abbas
Zare Mirakabadi
Department of Venomous Animals and Antivenom Production, Razi Vaccine and Serum Research Institute, Agriculture Research Education and Extension Organization, Karaj, Iran
author
Hamidreza
Mirzaei
Department of Radiation Oncology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Masoud
Mola
Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
Mohammad Hasan
Pezham
Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
Meysam
Karamivand
Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
author
Elham
Saniei
Islamic Azad University, Central Tehran Branch
author
text
article
2018
eng
Introduction: Venoms are a mixture of proteins and peptides which can be used for fighting cancers. They can affect the exposed fibers and the muscles directly or through motor nerves, causing neuromuscular intoxication. ICD-85 is a combination of three poly-peptides derived from the venoms of an Iranian brown snake and a yellow scorpion.
Materials and Methods: Technetium-99m was obtained from a 99Mo/99mTc generator. Venom (ICD-85) was provided by Razi Vaccine and Serum Research Institute of Iran. Labeling of this venom was achieved with Technetium-99m. Labeled ICD-85 was injected into mice to determine the organ targets and excretion pathway.
Results: Results show that the radiolabeling yield of the radio-venom is acceptable. The biodistribution study shows that the organs of liver, kidney and tumor are the targets of ICD venom. Also moderate clearance of the complex from blood was seen.
Conclusion: The results suggest that 99mTc radiolabeling of venom (ICD-85) may be a good tool for in-vivo studies and is an excellent approach to follow the process of biodistribution and kinetics of toxins for cancer imaging and treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
357
357
https://ijmp.mums.ac.ir/article_13021_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13021
Evaluating the performance of a 3D PLA buildup bolus in breast intraoperative radiotherapy.
Seyed Hamid
Zoljalali Moghaddam
Medical Physics Department, Iran University of Medical Sciences, Tehran, Iran
author
Hamid Reza
Baghani
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
author
Seyed Rabi
Mahdavi
Medical Physics Department, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: The received dose to the surface of tumor bed is one of the main issues in beast intraopeative radiotherapy (IORT). Totally, the administered dose to the surface is usually lower than that of radiotherapy reference point (distal end of tumor bed). Employing a buildup bolus can effectively increase the surface dose and therefore, eliminate such created cold points during IORT. The aim of this study is to evaluate the performance of a 3D buildup bolus, made of PLA (polylactic acid), for breast IORT.
Materials and Methods: A cubic PLA bolus with different infill percentage of 20% to 100%, with 10% increments, was simulated through BEAMnrc Monte Carlo code and irradiated by intraoperative electron energies of 6, 8, 10 and 12 MeV produced from LIAC IORT accelerator. The LIAC head was also modeled using BEAMnrc code. Then, the PDD curves for different infill percentages of studied bolus were calculated by the DOSXYZnrc code and compared with those obtained in water at various energies. All of comparisons were performed by gamma analysis and gamma index calculation. The dose difference and distance to agreement in gamma index calculations were considered as 2% and 2 mm, respectively.
Results: The results showed that high infill percentage corresponds to the high density and desirable homogeneity of bolus material. The bolus modeling in BEAMnrc code as a homogeneous material is satisfying for infill percentages greater than 20%. With increasing the bolus infill percentage, the accordance of obtained PDDs with those of water increments too. The PDD curves in the presence of PLA bolus with 100% infill percentage has the best agreement with the obtained PDDs inside water at different energies.
Conclusion: Based on the obtained results, it can be concluded that the dosimetric characteristics of high infill percentages of PLA material are compatible with those of water. Therefore, PLA can be considered as an effective buildup bolus for surface dose enhancement in breast IORT. By tuning the infill percentage of PLA material, one can change the dosimetric properties of obtained bolus. The best dosimetric results are obtained when the PLA bolus is made with 100% infill percentage.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
358
358
https://ijmp.mums.ac.ir/article_13022_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13022
The effect of melatonin on Superoxide dismutase and Glutathione peroxidase activity, and Malondialdehyde levels in the targeted and the non-targeted lung and heart tissues after irradiation in xenograft mice colon cancer
Seyede Hadis
Momeni Hasan Abadi
Department of Radiology and Radiotherapy Technology, School of Allied Health Sciences, Tehran University of Medical Sciences, Tehran, Iran
author
Alireza
Shirazi
Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Keshavarz Blvd, Poursina Ave, Tehran 468, Iran
Cancer Research Center, Tehran University of Medical Sciences, Tehran, Iran
author
Ali Mohammad
Alizadeh
Cancer Research Center, Tehran University of Medical Sciences, Tehran, Iran
author
Vahid
Changizi
Department of Radiology and Radiotherapy Technology, School of Allied Health Sciences, Tehran University of Medical Sciences, Tehran, Iran
author
Masoud
Najafi
Department of Radiology and Nuclear Medicine, School of Paramedical Science, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Solmaz
Khalighfard
Cancer Research Center, Tehran University of Medical Sciences, Tehran, Iran
author
Hasan
Nosrati
Cancer Research Center, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Introduction: Radiation causes damage to irradiated tissues and also tissues that do not receive direct irradiation through a phenomenon called bystander effects. Melatonin as a potent antioxidant and anti-inflammatory agent is known for protection of normal tissues against ionizing irradiation. In addition, some studies have suggested that Melatonin may have some anti-cancer properties. Although the complete mechanisms remain unknown, it can act via immunomodulatory effects. The aim of this study was to evaluate the effect of pretreatment with melatonin on oxidative damage caused by direct irradiation and bystander effects on the lung and heart tissue after xenograft mice colon cancer irradiation in Balb/c mice.
Materials and Methods: Forty nine (49) Balb/c mice were evenly divided into 7 groups including control, irradiation of 5 Gy directly to tumor, melatonin treatment (20 mg/kg) and irradiation (5 Gy single fraction) directly to tumor, irradiation of 5 Gy directly to chest area, melatonin treatment (20 mg/kg) and radiation directly to chest, only melatonin treatment and whole-body scatter group (which gave radiation dose equal to the amount of radiation that the lung had received from the localized pelvic irradiation) to evaluate the effect of melatonin on the MDA level as well as SOD and GPx activity after 24 and 72 h of irradiation of 5 Gy single fraction directly to the tumor tissue and chest area, in the tumor tissue, the lung tissue, and the heart tissue.
Results: The results revealed that exposure to irradiation resulted in an increase in MDA level and suppressed SOD and GPx activity in the targeted and non-targeted lung and heart tissues, and the tumor tissue. Melatonin decreased MDA level in the lung and heart tissues. Also, melatonin improved SOD and GPx activity in non-targeted tissues, while it was able to reduce these two enzymes and decreased MDA level in the tumor tissue.
Conclusion: Melatonin exhibited its ability to ameliorate oxidative stress in both targeted and non-targeted tissues. Administration of melatonin boosted SOD and GPx activity in the normal tissues, but not in the tumor cells. Through stimulation and suppression of the antioxidant system, Melatonin may cause sensitization of the tumor cells while protecting the normal tissues.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
359
359
https://ijmp.mums.ac.ir/article_13023_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13023
A method for range calculation of proton in liquid water: Validation study using Monte Carlo method and NIST data
Shiva
Zarifi
MSc. Student of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Hadi
Taleshi Ahangari
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Sayyed Bijan
Jia
Professor of physics, Department of Physics, Bojnord University, Bojnord, Iran.
author
Mohammad Ali
Tajik Mansoury
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Hossein
Mousavie Anijdan
Department of Medical Physics, Babol University of Medical Sciences, Babol, Iran
author
text
article
2018
eng
Introduction: The main advantage of using ion beams over photons in radiotherapy is due to their inverse depth-dose profiles, allowing higher doses to tumors, while better sparing normal tissues. When calculating dose distributions with ion beams, one crucial point is the uncertainty of the Bragg-peak range. Recently great effort is devoted to enhance the accuracy of the computation for proton treatments without increasing the calculation time. The highest accuracy in these calculations is obtained by Monte Carlo simulation methods. GATE is a Monte Carlo simulation platform based on geant4 which was found to be a convenient simulation environment to perform this study. This study shows how a stochastic method such as Monte Carlo can be utilized to obtain certain quantities of practical importance related to charged particle transport
Materials and Methods: In this study, GATE code was used to compute absorbed dose and fluence of protons in the energy range of 50-200 MeV and with energy step of 50 MeV. A water phantom (40*40*40 cm3) was modeled in a vacuum world volume (5*5*5 m3). Several physics lists have been defined in the GATE code that we used FTFP_BERT. The mono-energetic protons were emitted mono-directionally from a point source at one end of the water phantom. The simulations were carried out for 10^6 proton histories that yielded better than 0.3% statistical errors.
Results: In this study, we validated the Gate code in proton therapy applications. This study examined different physics lists and showed that the results obtained using FTFP_BERT physics are in a good agreement with NIST database. Our Results were compared to the CSDA ranges from NIST database using the GATE simulation code. The FTFP_BERT results showed good agreement within 1% for energies higher than 30 MeV and within 0.1% for energies higher than 70 MeV .We also conclude that the value of 0.1 mm is optimal for the SetCut.
Conclusion: The results were found to be ±0.1% compared to the data from the NIST compilation. It is safe to conclude that this approach can be extended to determine dosimetric quantities for other media, energies and charged particle types.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
360
360
https://ijmp.mums.ac.ir/article_13024_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13024
Monte Carlo calculation of proton ranges in water phantom for therapeutic energies
Shiva
Zarifi
MSc. Student of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Hadi
Taleshi Ahangari
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Sayyed Bijan
Jia
Professor of physics, Department of Physics, Bojnord University, Bojnord, Iran.
author
Mohammad Ali
Tajik Mansoury
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Elham
Kashian
MSc. Student of Biomedical Engineering, Department of Biomedical Engineering, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Majid
Jadidi
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
text
article
2018
eng
Introduction: One crucial point when calculating the distribution of doses with ions is the uncertainty of the Bragg peak. The proton ranges in determined geometries like homogeneous phantoms and detector geometries can be calculated with a number of various parameterization models. Several different parameterizations of the range-energy relationship exist, with different levels of accuracy and complexity. For benchmarking purposes and calibration of proton range, it is consequential to have an accurate computation scheme between ranges and energies. In this setting, Monte Carlo simulations became important more and more in order to evaluating treatment plans and dose distributions. High-resolution energy-range tables are created using the PSTAR database. The aim of this study is to calculate proton range in the range of therapeutic energy in a cubic water phantom with a submillimeter accuracy.
Materials and Methods: Various Monte Carlo packages are available today that are specifically developed for handling radiation transport problems. GATE (version8) was used in this study to model the geometry and composition of a phantom. Geometries dictated to the toolkit were a cubic water phantom (40*40*40 cm3), as the target sitting on the xy-plane with the z-axis as its axis of symmetry. The primary particle source, emitting protons, were in the proximity of the phantom base on the z-axis. Mono energetic proton pencil beams (50, 100, 150, 200 MeV) hit the phantom. Several physics lists are defined in the GATE that we used FTFP_BERT. The simulations were carried out for 106 proton histories that yielded better than 1% statistical errors.
Results: In the current study, the results of the Bragg Peak Profile for the energy range of 5-
200 MeV has been obtained. The range-energy relation was obtained by fitting the FTFP_BERT physics data. So far, many similar studies have been done in this regard, such as a study by Bozkurt using the MCNPX code. However, we investigated the overall energy range used in proton therapy and obtained the fit model using a greater bunch of data.
Conclusion: By comparing the results obtained for each energy with NIST data, and with using Shapiro-Wilk statistical test, we did not see any significant difference. It was also found by calculating the percentage difference obtained with the CSDA data available in the NIST library, with the highest difference of 0.5%.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
361
361
https://ijmp.mums.ac.ir/article_13025_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13025
Statistical uncertainty estimation in the calculation of the proton range in water phantom.
Shiva
Zarifi
MSc. Student of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran. 2.Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Hadi
Taleshi Ahangari
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Sayyed Bijan
Jia
Professor of physics, Department of Physics, Bojnord University, Bojnord, Iran.
author
Mohammad Ali
Tajik Mansoury
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Elham
Kashian
MSc. Student of Biomedical Engineering, Department of Biomedical Engineering, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Peyman
Hejazi
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
text
article
2018
eng
Introduction: GATE (Geant4 Application for Tomographic Emission) is a Monte Carlo simulation platform developed by the OpenGATE collaboration since 2001 and first publicly released in 2004. In Geant4, each physics process is described by a model (several models are sometimes available for a given physics process) and a corresponding cross-section table. All Geant4 physics models and cross-sections below 10 GeV are now available in GATE. In particular, models describing the transport of optical photons and hadronic interactions have recently been introduced. The purpose of this study is to investigate the physics lists of the Geant4 code, as well as to examine the accuracy of energy deposition and statistical uncertainty in the calculation of the dose.
Materials and Methods: In this study, GATE code was used to compute absorbed dose and fluence of protons in the energy range of 50-200 MeV and with energy step of 50 MeV. A water phantom (40*40*40 cm3) was modeled in a vacuum world volume (5*5*5 m3). Several physics lists have been defined in the GATE code that we used FTFP_BERT. The mono-energetic protons were emitted mono-directionally from a point source at one end of the water phantom. The DoseActor has been added to store distributions of dose with the associated statistical uncertainty in any volume The simulations were carried out for 10^6 proton histories that yielded better than 0.3% statistical errors.
Results: In the current study, we obtained normalized energy deposited for 5-200 MeV proton beams as a function of depth in water and its associated relative statistical uncertainty. The statistical uncertainty for all voxels before the Bragg peak is below 0.01%. Fluctuations after the Bragg peak are due to near zero values of deposited energy at these depths.
Conclusion: The results of this study showed that the statistical uncertainty of the dose in the energy of 200 MeV is about 0.25%. And by calculation the difference of proton ranges in this energy with NIST data, it is seen that this difference is greater than the statistical uncertainty. In order to obtain more accurate results, it is suggested that the accuracy of other physics lists is also examined..
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
362
362
https://ijmp.mums.ac.ir/article_13026_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13026
Study the effect of source to diaphragm distance (SDD) on beam penumbra width of Gamma Knife machine model 4C using Monte Carlo simulation
Atefeh
Mahmoudi
Master Student, Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
author
Ghazale
Geraily
Assistant Professor, Medical Physics and Biomedical Engineering, Department, Tehran University of Medical Sciences, Tehran, Iran
author
Alireza
Shirazi
Full Professor, Medical Physics and Biomedical Engineering, Department, Tehran University of Medical Sciences, Tehran, Iran
author
Masoume
Bakhshi
Master Student, Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Stereotactic radiosurgery (SRS) is one of the conformal radiotherapy methods and Gamma Knife is a non-invasive SRS technique to treat intracranial lesions with 201 Co- 60 sources without need to surgery and bleeding. Beam penumbra phenomenon leads to irradiation outside the field and normal tissues. Therefore, considering it is momentous to attain the acceptable treatment plan.
Materials and Methods: In this study, Gamma Knife unit was modeled using EGSnrc/BEAMnrc Monte Carlo code. SDD (Source to Diaphragm Distance) parameter that is one of the affecting factors on physical penumbra width was studied. For this purpose, SDD was increased for 4, 8, 14 and 18 mm collimator sizes in five steps and each step as much as one centimeter. Single beam profiles were calculated using EGSnrc/DOSXYZnrc code at isocentre depth in a cubic Plexiglas phantom. MATLAB and EXCEL software were used to plot profiles and measure physical penumbra width
.
Results: Based on the results, physical penumbra width (90%-50%) does not show a regular trend with increasing SDD. This may be attributed to scatter radiation which is due to the low distance between the Gamma Knife collimator end and phantom surface. Best results were observed for 4 and 8 mm collimators in 1 cm increase in which penumbra width decreased from 0.785 and 0.790 mm to 0.749 and 0.736 mm for 4 and 8 mm collimator sizes, respectively.
Conclusion: It is recommended to increase SDD of Gamma Knife 4C around 1 centimeter to reduce penumbra width for small tumor sizes located near the critical nerves.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
363
363
https://ijmp.mums.ac.ir/article_13027_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13027
Investigating Indoor Radon Concentration Using CR-39 Detector; a Case Study of Gachin Dwellings in Hormozgan
Ali
Jamjour
Department of Medical Physics, Fasa University of Medical Science, Fasa, Fars, Iran.
author
Gholamhassan
Haddadi
Department of Medical Physics, Fasa University of Medical Science, Fasa, Fars, Iran.
author
text
article
2018
eng
Introduction:
Radon is a colorless inert gas which decay products are the main component of natural radioactive elements that are naturally produced in under layers of earth crust by decay of radium and uranium. It enters through buildings via gaps and cracks. Radon gas decay products like alpha particle can increase the incidence of lung cancer in human. Since every person spends a great part of his life in closed environments including house, office, factory, and etc. elevated amount of radon gas could influence human heath negatively. Therefore, it is crucial to understand how the concertation of radon gas is in different buildings with different materials. In this line, the study aims to measure the concentration of radon gas in the dwellings of Gachin village.
Materials and Methods:
In this regard, solid-state nuclear track detectors (CR-39) was used in 69 homes of Gachin village. Each CR-39 detectors were mounted 50-90 cm from the bottom bedroom and living rooms, away from doors and windows. After about three months of exposure, the detectors were collected and transported to the laboratory to be analyzed.
Results:
The result showed that there is significant difference between the concentrations of radon gas in houses with different materials. Houses constructed with concrete had the lowest concentration of radon gas while houses constructed with clay bricks had the highest concentration of it.
Conclusion:
The result of this study could be used in mapping of national radon level. Moreover, It provides important information for policy makers and planners to design programs for alleviating current concentration of radon gas in Gachin dwellings which would lead to lower lung cancer risk.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
364
364
https://ijmp.mums.ac.ir/article_13028_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13028
Assessment of a 2D EPID-based Dosimetry Algorithm for Pre-treatment and In-vivo Midplane Dose Verification
Ali
Jomehzadeh
Department of Medical Physics, Kerman University of Medical Sciences, Kerman, Iran.
Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
author
Parvaneh
Shokrani
Department of Medical Physics, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Mohammad
Mohammadi
.Medical Physics Department, Royal Adelaide Hospital. Adelaide, SA 5000, Australia
author
Alireza
Amouheidari
Department of Radiation Oncology, Isfahan Milad Hospital, Isfahan, Iran.
author
Anton
Mans
Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
author
Ben
Mijnheer
Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
author
text
article
2018
eng
Introduction: The use of electronic portal imaging devices (EPIDs) is a method for the dosimetric verification of radiotherapy plans both pretreatment and in-vivo. The aim of this study was to test a 2D EPID-based dosimetry algorithm for dose verification of some plans inside a homogenous and anthropomorphic phantom and in-vivo, as well.
Materials and Methods: Dose distributions were reconstructed from EPID images using a 2D EPID dosimetry algorithm inside a homogenous slab phantom for a simple 10×10 cm2 box technique, the 3D conformal (prostate, head-and-neck and lung) and an IMRT prostate plans inside an anthropomorphic (Alderson) phantom and the patients (one fraction in-vivo) for the 3D conformal plans (prostate, head-and-neck and lung).
Results: The Planned and EPID dose difference at isocenter, on average, was 1.7% for the pretreatment verification and was less than 3% for all in vivo plans except a head-and-neck which was 3.6%. The mean γ values for a 7-field prostate IMRT plan delivered to the Alderson phantom varied from 0.28 to 0.65. For 3D conformal plans applied for the Alderson phantom, all γ1% values were within the tolerance level for all plans and in both AP-PA beams.
Conclusion: The 2D EPID-based dosimetry algorithm provides an accurate method to verify the dose of a simple 10×10 cm2 fields in two dimensions inside a homogenous slab phantom as well as for IMRT prostate plan and 3D conformal plans (prostate, head-and-neck and lung plans) applied using an anthropomorphic phantom and in-vivo.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
365
365
https://ijmp.mums.ac.ir/article_13029_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13029
Interpretation of In-air Output Ratio of Wedged Fields in Different Measurement Conditions
Faride
Biglari
Department of Medical Physics, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Parinaz
Mehnati
Medical Radiation Sciences Research Team, Department of Medical Physics, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Ali
Jomehzadeh
Department of Medical Physics, Kerman University of Medical Sciences, Kerman, Iran.
author
text
article
2018
eng
Introduction: The head scatter factor (Sc) is one of the important parameters for monitor
unit (MU) calculation. There are multiple factors that impact the Sc values, such as, head
structures, back scattering in to dose monitoring chambers, wedges and so on. This study
aimed to investigate the variations of SC with different build-up cap materials, wall thickness, Source to Skin Distance (SSDs), ionization chambers and variation of the SC with wedge
angles in 6MV photon beam.
Materials and Methods: In this study, Copper and Perspex build-up caps were designed and
fabricated with two different thicknesses for each build-up cap. Measurements were
performed on an Elekta Compact medical linear accelerator (6 MV) using RK with sensitive
volume of 0.12 cc and Farmer-type ion chamber with sensitive volume of 0.65 cc. In all
measurements, build-up caps and ionization chambers were positioned in a stand vertical to
the beam central axis. It is also investigated the effect of different SSDs on SC.
Results: The presence of wedge influences the SC values significantly. Variation of SC in open
and wedged fields had maximum deviation of 0.9% and 6.8% and minimum of 0.4% and
2.7% for 30° and 60° angles of wedge, respectively. different SSD and type of ion chamber
had no significant influence on the SC. In small field sizes, the SC values in copper build-up cap
is higher than Perspex and in large field sizes, measured SC in perspex build-up cap is higher
than copper.
Conclusion: It was found that the presence of internal wedge has significant contribution to
head scatter factor and it increases with increasing wedge angle. Therefore, it should be
takes into account in manually MU calculations.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
366
366
https://ijmp.mums.ac.ir/article_13030_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13030
Dose-volume Analysis of Heart and Lung during 3D Planning of Tangential Breast Cancer Irradiation
Ali
Jomehzadeh
Department of Medical Physics, Kerman University of Medical Sciences, Kerman, Iran.
author
Mohammad Hasan
Larizadeh
Department of Radiation Oncology, Kerman University of Medical Sciences, Kerman, Iran
author
Zahra
Jomehzadeh
Department of Medical Physics, Kerman University of Medical Sciences, Kerman, Iran.
author
text
article
2018
eng
Introduction: Breast cancer is becoming more frequently diagnosed at early stages with improved long-term outcomes. Radiation-related heart disease and lung cancer can occur following radiotherapy for breast cancer. The aim of this study was to evaluate some dosimetric parameters of heart and lung during whole breast radiotherapy.
Materials and Methods: Twenty-five consecutive patients with breast cancer who underwent radiotherapy were included in this study. Plans that employed the 3D conventional radiotherapy technique (Tangential Technique) were generated for each patient. Dose-volume histograms (DVHs) were calculated and dosimetric parameters such as, mean dose/volume receiving a dose 30 Gy (V30), mean dose/ volume receiving a dose 20 Gy (V20) for heart and lung were assessed, respectively. Results: The average of mean dose of heart on left and right side irradiation was 9.68±5.10 Gy and 1.23±1.51 Gy, respectively. The average of mean dose of ipsilateral lung on left and right-sided irradiation was 14.49±4.07 Gy and 11.69±3.37 Gy, respectively. The percentage of heart volume that received at least 30 Gy was 16.32±9.56% for left-sided treatment. The percentage of lung volume that received at least 20 Gy was 23.47±11.05% and 24.12±7.77% respective on the left and right-sided breast irradiation.
Conclusion: Tangential beam conventional radiotherapy of the chest wall of postmastectomy breast cancer patients provides the potential to significantly keep the DVH parameters of heart and lung as low as the QUANTEC constrains.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
367
367
https://ijmp.mums.ac.ir/article_13031_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13031
Effect of Material and Wall Thickness Buildup Caps on the Head ScatterFactor Measurements in Irregular Fields Shielded by Cerrobend
Vahid
Jahanbakhsh
Department of Radiotherapy Physics, Shafa Kerman Hospital, Kerman, Iran.
author
Daryoush
Shahbazi-Gahrouei
Department of Medical Physics, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Ali
Jomehzadeh
Department of Medical Physics, Kerman University of Medical Sciences, Kerman, Iran
author
text
article
2018
eng
Introduction: The head scatter factor (Sc) is important to measurements radiation beam
and beam modeling of treatment planning systems used for advanced radiation therapy
techniques. This study aimed to investigate the design of a mini-phantom to measurement variations in collimator Sc in the presence of shielding blocks for shaping the beam using different field sizes.
Martials and Methods: Copper, Brass, and Perspex buildup caps were designed and
fabricated locally as material with three different thicknesses for buildup caps (mini-
phantoms). Measurements were performed on an Elekta Compact medical linear accelerator
(6MV) in Shafa Kerman Hospital, Iran. The Farmer-type ion chamber FG65-P (Scanditronix,
Wellhofer) was used for all measurements. To measure the Sc, mini-phantom was positioned
in a stand vertical to the
beam central axis.
Results: The data indicated that the Sc measurements using different buildup cap materials
and thicknesses in 5 × 10, 7.5 × 7.5, and two 10 × 10 cm Cerrobend shield blocks ranged 0.98
to 1.00, 1.04 to 1.05, and 1.04 to 1.06, respectively. Also, it was observed that by increasing
the block shield area from 50 cm2 to both 56.25 and 100 cm2, the Sc increased in all
situations.
Conclusion: We concluded using Brass compared to Perspex and Copper has less
uncertainty due to its simple preparation and cutting which is useful to measurement of
variations in collimator Sc.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
368
368
https://ijmp.mums.ac.ir/article_13032_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13032
Rn- 222 Concentration and Gamma Dose Rate Measurements in the Vicinity of Hot Springs in Kerman Province, Southeastern, Iran.
Vahid
Doostmohammadi
Department of Medical Physics, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Parinaz
Mehnati
Medical Radiation Sciences Research Team, Department of Medical Physics, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Ali
Jomehzadeh
Department of Medical Physics, Kerman University of Medical Sciences, Kerman, Iran.
author
text
article
2018
eng
Introduction: Radon-222 gas is a radioactive, colorless and odorless element that can cause lung cancer and stomach in humans with alpha-ray emissions. An important source of Radon-222 is the output water in springs, especially hot springs to emit ionision radiation. In this study, Rn-222 activity concentration and gamma dose rate levels in water sample of some selected hot springs were measured.
Method: The activity concentration of Rn-222 in water samples and gamma dose rates were measured using RAD7 radon monitoring system (a solid-state detector) of Durridge company Inc, USA and RDS-110 multi-purpose survey meter respectively from five randomly selected hot springs. The RAD7 detector has a glass bottle of 250 ml capacity for measurement Rn-222 concentration via bubble making process.
Results: In water samples taken from the orifice of Shirinak, Rang, Khodadadi, Amiriyeh and Joshan hot springs, the specific Rn-222 concentrations were 4.74±0.65, 7.46±1.27, 8.96±1.20, 15.70±2.17 and 56.10±5.68 BqLit-1, respectively. Also, the average absorbed dose rates in vicinity of hot springs varied from 80±14 nSvh-1 to 188±31 nSvh-1.
Conclusion: We concluded, radon concentration activities were in the range of the US Environmental Protection Agency reference limit and gamma dose rate level was less than recommended by USCEAR, as well. Hence, there is no need radiation protection for people who used the selected hot springs.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
369
369
https://ijmp.mums.ac.ir/article_13033_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13033
Application of Artificial Neural Networks in a Two-step Classification for Acute Lymphocytic Leukemia Diagnosis by Blood Lamella Images
Arman
Zamani
Master of Electronic Engineering, Ayatollah Khansari Hospital, Arak, Iran
author
Ghasem
Babaei
PHD, Faculty of Engineering, University of Khomein, Khomein, Iran
author
Nayyer
Mostafavi
Msc of Medical Physicists, Ayatollah Khansari Hospital, Arak, Iran
author
text
article
2018
eng
Introduction: This study aimed to present a system based on intelligent models that can enhance the accuracy of diagnostic systems for acute leukemia. The three parts including preprocessing, feature extraction, and classification network are considered as associated series of actions. Therefore, any dysfunction or poor accuracy in each part might lead in general dysfunction of the whole system.
Materials and Methods: In the current study, rgb2hsv code and two-dimensional Wiener were used for the preprocessing part. In addition, fuzzy C-means method was applied for the segmentation step and nervous networks-based techniques as well as support vector machines were utilized in the classifying networks.
Results: The results of the proposed method were compared with other training methods; demonstrating that 91.4% as the lowest and 95.7% as the highest mean accuracies belonged to Gradient Descent with "Adaptive Thresholding" and "Resilient Back propagation", respectively. Moreover, the results revealed that regarding the outputs accuracy, 48% as the lowest and 95.7% as the highest mean test accuracies were related to the MPN and proposed networks, respectively.
Conclusion: The application of the proposed network in this study is that eliminate the weak points of all the networks in addition to presenting the advantages of these network. Combining the networks improved the accuracy of output up to 98% and considerably reduced the time required for calculations. It could be concluded that we can reach a more accurate network with less hardware facilities.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
370
370
https://ijmp.mums.ac.ir/article_13034_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13034
Effective Source-Surface Distance in Various Field Sizes and Electron Beam Energies and its Effect on Cutout Factor in a Elekta Precise Linear Accelerator
Fateme
Fallahi
Department of Medical Physics, School of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran
author
Mohamad Reza
Bayatiani
Department of Medical Physics and Rariotherapy, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran
author
Fatemeh
Seif
Department of Medical Physics and Rariotherapy, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran
author
Akbar
Aliasgharzadeh
Department of Medical Physics, School of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran
author
Fatholah
Mohaghegh
Department of Medical Physics and Rariotherapy, Arak University of Medical Sciences and Khansari Hospital, Arak, Iran
author
text
article
2018
eng
Introduction: In electron beam treatment, because of the non-point electron beam source, inverse-square law cannot be applied for dosimetry in different treatment intervals. Therefore, providing source-surface distance (SSD) charts in all clinics is of paramount importance. This study aimed to determine the effective SSD for various electron beam energies and field sizes and to evaluate its effect on cutout factor in a linear accelerator.
Materials and Methods: We used Elekta Precise linear accelerator in Ayatollah Khansari Hospital, Arak, Iran, for various energy levels (10, 15, and 18 MeV). The measurement environment was MP3-M water phantom (PTW Co., Canada), and diode detector was utilized for dosimetry. The effective SSD and cutout factor was estimated for 100, 105, 110, 115, and 120 cm SSDs and 1.5×1.5 and 20×20 cm2 square fields.
Results: The effective SSD in the 1.5×1.5 to 20×20 cm2 fields altered from 29.95 to 93.95 cm,
50.40 to 96.50 cm, and 63.51 to 95.32 cm for different energy levels of 10 MeV, 15 MeV, and 18 MeV, respectively. The cutout factor increased along with the field size, but decreased by extending the SSD. These alterations were more significant for the energy level of 10 MeV.
Conclusion: Since the effective SSD is dependent on energy level and field size, it is recommended to independently compute the effective SSD considering these variables. Furthermore, for designing accurate therapies, cutout factor variations should be considered for small-sized fields, especially at low energy levels.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
371
371
https://ijmp.mums.ac.ir/article_13035_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13035
AS1411 Aptamer Conjugated Gold Nanoclusters as a Targeted Radiosensitizer for Megavoltage Radiation Therapy of 4T1 Breast Cancer Cells
Fatemeh
Ghahremani
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran. Bahare.ghahremani@gmail.com
author
Amirhosein
Kefayat
Department of Oncology, Seyed Al-Shohada Hospital, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran, ahkefayat@yahoo.com
author
Daryoush
Shahbazi-Gahrouei
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran. shahbazi@med.mui.ac.ir
author
text
article
2018
eng
Introduction: In the present study, AS1411 aptamer conjugated gold nanoclusters (GNCs) have been introduced as a targeted radiosensitizer for enhancing megavoltage radiation therapy efficacy. RT has identified as an effective therapeutic modality for many different types of solid tumors. However, equal radiation beams absorption by tumor and surrounding healthy tissues is still a great challenge in RT which is caused by attenuation coefficient factor similarity. In order to overcome this challenge and to increase the efficacy of radiation therapy, radiosensitizers has been recommended.
Materials and Methods: GNCs with ultra-small gold core and bovine serum albumin shell (BSA) as a versatile Nano-platform were synthesized and conjugated to AS1411 aptamer (Apt-GNCs). Due to nucleolin overexpression in breast cancer cells and high affinity of the AS1411 aptamer to nucleolin, mouse mammary carcinoma cell line (4T1) was selected as malignant cells and murine fibroblast (L929) was used as a normal cell line.
Results: Flow cytometry assessments reveal a significant increase of GNCs uptake by the cancer cells in the presence of the aptamer as the targeting agent. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements demonstrate 4 times more Apt-GNCs uptake by 4T1 cells than the normal cells at concentration ratio of 1:40 (4µM Aptamer and 160 µM GNCs at 24h incubation).
Conclusion: Combination of megavoltage radiation therapy and Apt-GNCs as radiosensitizer causes effective cancer cells killing and obtaining dose enhancement factor (DEF) about 2.7 in clonogenic survival assay.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
372
372
https://ijmp.mums.ac.ir/article_13036_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13036
Comparison between two different methods used for IMRT plans QA of Prostate cancer
Farzaneh
Shirzad
Department of Nuclear Engineering Central Tehran Branch of Islamic Azad University, Tehran, Iran.
author
Mohsen
Bakhshandeh
Department of Radiology, Faculty of Allied Medical Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mehdi
salehi Barough
Department of Nuclear Engineering Central Tehran Branch, Islamic Azad University, Tehran, Iran.
author
Ali
Jabbary
Department of Medical Physics, Shohada –e- Tajrish Hospital, Tehran, Iran.
author
Mona
Malekzadeh
Department of Radiotherapy & Oncology, Shohada- e- Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: The aim of this study is evaluation of two Quality Assurance methods in sliding window IMRT technique and Determination of gamma index in both methods
Materials and Methods: In this study two tools named" Delta4" phantom and " Epiqa" software has been used to perform QA on the treatment plan before the actual treatment by Varian linear accelerator Clinac 600C. For this purpose, 20 patient’s treatment plan were assessed with the 3% and 3mm criteria.
Results: Each treatment field demonstrated that the gamma index in the delta4 phantom was more than the Epiqa software for all patients. The most uncertainty for a treatment plan in delta4 phantom was 0.88% and for Epiqa software was 1.53%. (p- value <0.05)
Conclusion: In spite of these variations in results and also studying similar researches, these tools can be used as a reliable QA method in radiotherapy centers. Delta4 phantom is preferred to Epiqa software because it is a dosimeter. However, Epiqa software is economical to install. therefore can be used for those centers which cannot afford delta4 phantom due to economic consideration.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
373
373
https://ijmp.mums.ac.ir/article_13037_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13037
Measurement Of Scatter Factors For Small Photon Fields Using Gaf chromic EBT2 Film
Fariba
Eyni
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Nahid
Chegeni
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mohammad Javad
Tahmasebi Birgani
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Seyed Mojtaba
Hosseini
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Maryam
Atarod
Department of Medical Physics, School of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran.
author
text
article
2018
eng
Introduction: Small field dosimetry is challenging for radiotherapy dosimetry. measurement of the output factor in the air and water (Sc, Scp) is one of the input parameters for commissioning of treatment planning systems and beam modeling. The aims of this study are to measured Sc,Scp for small fields with EBT2 and Ion chamber and design a appropriate mini-phantom for small fields dosimetry with EBT2 film.
Materials and Methods: output factors in air and water were measured for Siemens linear accelerator 6Mv energy and fields sizes (1-20cm) which irradiated by 200MU. Measurements were performed using a gafchromicfilm EBT2 and 0.6cc Farmer ion chamber and then the results were compared with Report of AAPM Group74 and TG155. For lateral electron equilibrium and electron contamination removal, two top of the water and Cerrobend were designed for film dosimetry and plexiglass buildup cap for Farmer chamber was applied.
Results: It was observed that In-air output factors increased with field size, and this increase in Cerrobend top is less than water top and Farmer dosimeter.Sc measured in small field is good agreement with data TG74 (0.5%), also Scp result were compared with data TG155(4.1%), and the response of the film to the Ion chamber isalso in good agreement showed (2.4%).
Conclusion: EBT2 film in measured output factors in air and wayer for small field as a good alternative to ion chamber dosimeters known as a standard dosimeter.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
374
374
https://ijmp.mums.ac.ir/article_13038_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13038
The effect of high energy photon beam in dose- volume parameters and integral dose of normal structures in Head and neck IMRT
Golbarg
Esmaili
Ph. D of medical physics. Pars Hospital radiotherapy center. Tehran, Iran.
author
Seied rabi
Mahdavi
Associate Professor of Medical physics. Medical physics Dept. Iran University of Medical Sciences. Tehran, Iran
author
Alireza
Nikoofar
Assistant Professor of Radiation Oncology. Radiation Oncology Dept, Faulty of Medicine, Iran University of Medical Sciences. Tehran, Iran.
author
text
article
2018
eng
Introduction:
The aim of this study is to investigate the effect of partially used high photon energies on dosimetric parameters and integral doses of nasopharynx IMRT plans.
Materials and Methods:
Two 7 coplanar IMRT plan were created for eleven patients (6 MV only IMRT plan in both phase1 and phase2 and 6 MV phase1-mixed energies (6 MV and 15 MV) phase2) with the equivalent dose constraints. The plans comparison was based on dose- volume histogram. Organ at risk sparing and the integral dose of normal structures were analyzed for target coverage, D95% to PTV50 and PTV70, V77 for PTV70, HI, and CI for both PTVs.
Results:
High energy IMRT plan (6 MV phase1- mixed energy phase2) had better outcome for D95% of PTVs compared to 6 MV only IMRT plan (68.84 and 71.5 for PTV70 in 6MV, and 6MV-mixed, respectively). In addition, D95% for PTV50 were 48.11and 49.2, respectively. Despite energies, HI and CI of the two plans were identical with each other. There were somewhat increase in V77 and Dmean of PTV70 for 6 MV-mixed compared to 6 MV plan but still in the tolerance limit. The 6 MV-mixed plan successfully reduced the Dmean, Dmax, D50% of organ at risks were compared to 6MV only technique. Moreover, volume getting 1,5,10, 30, 50 and 70 Gy and total integral doses of OARs and normal tissue plus IDs of OARs receiving low, mid and high dose regions were reduced by high energy plan.
Conclusion:
Our Results stated that using partial high energy photon beams can make an improvement dosimetry results in the head and neck IMRT treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
376
376
https://ijmp.mums.ac.ir/article_13040_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13040
An investigation of the effect of hyperthermia using iron and magnetic nanoparticles in cancer treatment
Ramin
karimian
Chemical Injuries Research Center, Systems biology and poisonings institute, Baqiyatallah University of Medical Sciences, Tehran, Iran. Email: b.goldoostt@yahoo.com, phone: +98 9380434304
author
Bagher
Goldoost
Msc student of medical physics, Baqiyatallah University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: hyperthermia using different methods such as microwave and magnetic waves is one of the methods to treat cancer. In this method, iron and magnetic nanoparticles are used to increase the temperature and increase the effect of hyperthermia as auxiliary treatment with chemotherapy and radiotherapy. In this study, the role of iron and magnetic nanoparticles have been compared in increasing the tumor temperature and maintaining healthy tissue and thus increasing the efficiency of hyperthermia with radiotherapy.
Materials and Methods: After cultivating and proliferating SGC-7901 cell line derived from gastric cancer, iron and magnetic nanoparticles were injected into tumors separately in two different groups, using microwave and magnetic waves irradiation their temperature was increased to upper than 43 ° C, and then 48 hours after irradiation, cell survival was evaluated using MTT method to investigate the effect of iron and magnetic nanoparticles.
Results: Cell survival was achieved as a result of hyperthermia and radiotherapy in the presence of metal and magnetic nanoparticles 18% and 21% respectively.
Conclusion:
The presence of both groups of iron and magnetic nanoparticles during microwave and magnetism waves irradiation increased cell death in cultured cells. The results of our study showed that iron nanoparticles are less concentrated in comparison to magnetic ones, causing a rapid rise in temperature, which increases the efficiency of hyperthermia and reduces damage to healthy tissues around the tumor.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
377
377
https://ijmp.mums.ac.ir/article_13041_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13041
dimensional film dosimetry with GAFCHROMIC films for quality assurance and dosimetric verification of 3D conformal radiotherapy in the presence of heterogeneities
Leila
Mahani
Department of Medical Physics, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
author
Ahad
Zeinali
Department of Medical Physics, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
author
Kamal
Mostafanezhad
Radiotherapy Department, Omid hospital, , Urmia, Iran
author
Milad
Zeinali Kermani
Department of Medical Physics, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
author
text
article
2018
eng
Introduction: The presence of heterogeneities such as air-filled cavities in the head and neck treatment fields region, may result in potential dosimetric disagreement because the losses of charged particle equilibrium. Most of treatments planning systems are not able to predict dose distribution of inhomogeneities region accurately. Therefore, dose calculation algorithms need to model electron transport accurately. GAFchromic films are used in routine radiotherapy quality assurance procedure to perform comprehensive dosimetry. The development and using 3D dosimetry may be useful.
Materials and Methods: several pieces of GAFchromic films were embedded in an in-house manufactured rectangular inhomogeneous head and neck phantom. A 6 MV photon beam from a Siemens Primus linear accelerator, equipped with the standard multileaf collimator (MLC) was assessed. Different approximately small field sizes were examined. A homemade computer code was developed for reconstruction of 3D dose map of irradiated Gafchromic. The measured data by film were compared to the similar data calculated by TPS in dose- volume histogram (DVHs).
Results: The data calculated by TPS compared with the measure data based on 3- dimensional film dosimetry. Our results showed significant differences between the results of the film dosimetry and TPS. Maximum difference of calculated and measured values observed for volume enclosed in 95% isodose curves and 3x3cm2 field size (P=0.035). For this field size the dose calculated by TPS, after the air cavity differed from the film measurements on average by 42%. The disagreement between measured and calculated data was increased with decreasing of field size.
Conclusion: our results demonstrated this TPS based on full scatter convolution algorithm doesn’t have acceptable performance in heterogeneous regions and approximately small fields and overestimated dose at some areas like air cavity or interface of air/tissue. Also our results confirmed that utilization of some accurate and comprehensive method such as 3D film dosimetry can be useful beside other methods of QA methods.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
378
378
https://ijmp.mums.ac.ir/article_13042_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13042
Investigating of relationship between the parameters related to the treatment planning and the biological parameters in radiation induced pneumonitis in breast cancer patients
Maede
Hasan Abdali
M.Sc in Medical Physics, Student Research Committee, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran. m_abdali68@yahoo.com
author
Karim
Khoshgard
Assistant Professor, Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Abdolazim
Sedighi Pashaki
MD in Radiation Oncology, Department of Radiation Oncology, Mahdieh Radiotherapy Center, Hamedan, Iran. a.sedighipashaki@gmail.com
author
text
article
2018
eng
Introduction: The purpose in this study is to analyze of DVH parameters as predictors of radiation pneumonitis and investigation on the relationship between dosimetric and clinical parameters based on PFTs as response in NTCP model and therefore achieve to lung dose- response relation in breast cancer patients. Prescribed dose to treatment volumes was 50 Gy in 2.0 Gy/fractions
Materials and Methods: Clinical and dosimetric data for 51 patients with stages II, III breast cancer who were undergone modified radical mastectomy (MRM) or mastectomy, and they had received prior chemotherapy with a same regimen of 8 steps, were included. Dose delivery technique was SAD and the prescribed dose was 50 Gy in 25 fractions. All of these pulmonary function tests were done before and after completion of radiotherapy, 3 and 6 months afterwards. Relationship between dosimetrical and clinical parameters patients are analyzed according to the univariate logistic regression and by Lyman NTCP model for investigation probability SRP.
Results: All of these pulmonary function tests (PFTs) were decreased after completion of radiotherapy, and 6 months afterwards. According to our results, in this research pulmonary complications has appeared from six months after treatment. 17 patients (33.3%) were with radiation pneumonitis without symptoms and 5 (9.8%) patients suffering radiation pneumonitis symptoms with grade 2. Lyman NTCP model parameters were obtained for prediction radiation pneumonitis.
Conclusion: Lung dose- response relation was obtained and analyzed according to Lyman NTCP model and DMH as input data in Lyman NTCP model comparison of DVH. IV20, irradiated volume and mass and mean lung dose parameters are related with radiation pneumonitis in patients. Our results indicated that pulmonary function changes occurs at 6 months after RT. we present that in the structure as lung, DMH concept has important effect in the Lyman model
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
379
379
https://ijmp.mums.ac.ir/article_13043_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13043
DNA Damages on Blood Cells After Cardiac Magnetic Resonance Imaging
Mohsen
Shoja
Depatment of Radiology, Faculty of Paramedicine, Semnan University of Medical Sciences, Semnan, Iran
author
Niloufar
Asbaghipour
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
author
text
article
2018
eng
Introduction: Along with the increased use of cardiac imaging at clinics there is increased attention to the potential risks related to the methods used like magnetic resonance (MR) and it cannot be ruled out that MR can alter DNA structure. The aim of this review is to assess the impact of routine cardiac magnetic resonance (CMR) scanning on DNA damages in human T lymphocytes.
Materials and Methods: The study was a systematic review for assessment of DNA damages on human T lymphocytes after CMR, where relevant articles of base such as Google Scholar, Scopus, Elsevier and PubMed with the key words of cardiac magnetic resonance, DNA damage and lymphocytes, in years 2012 to 2017 were searched and analyzed.
Results: CMR imaging requires some of the strongest and fastest switching electromagnetic gradients available in MR, exposing the patients to the highest accepted energy levels. Fiechter et al. showed significant DNA damage in patient T lymphocytes as soon as 1 or 2 hours post CMR. Several studies reported an immediate post-MRI increase of histone H2AX phosphorylation (γ-H2AX) in lymphocytes, a marker of DNA double-strand breaks
Conclusion: Our study proved the association between CMR scanning and DNA DSBs in T lymphocytes but the cellular mechanism is not known and may be different from that of radiation. Nonetheless, there have been limited numbers of investigations which examined whether in vitro and/or in vivo exposure of cells to electromagnetic fields used in MRI can cause significantly excess genetic damage. So further studies are necessary in more detail.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
380
380
https://ijmp.mums.ac.ir/article_13044_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13044
The comparison between 6 MV Primus LINAC simulation output using EGSnrc and commissioning data
Mohammad
Davoudi
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran
author
Ali
Shabestani Monfared
Professor of Medical Physics, Radiotherapy Physicist, Babolsar Oncology Hospital, Department of Medical Physics, Babol Univetsity of Medical Sciences, Babol, Iran.
author
Mohammad
Rahgoshay
Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
text
article
2018
eng
Introduction: Monte Carlo calculation method is considered to be the most accurate method for dose calculation in radiotherapy. The purpose of this research is comparison between 6 MV Primus LINAC simulation output with commissioning data using EGSnrc and build a Monte Carlo geometry of 6 MV Primus LINAC as realistically as possible. The BEAMnrc and DOSXYZnrc (EGSnrc package) Monte Carlo model of the LINAC head was used as a benchmark.
Materials and Methods In the first part, the BEAMnrc was used for the designing of the LINAC treatment head. In the second part, dose calculation and for the design of 3D dose file were produced by DOSXYZnrc. The simulated PDD and beam profile obtained were compared with that calculated using commissioning data. Good agreement was found between calculated PDD (1·1%) and beam profile using Monte Carlo simulation and commissioning data. After validation, TPR20,10, TMR and Sp values were calculated in five different field.
Results Good agreement was found between calculated values by using Monte Carlo simulation and commissioning data. Average differences for five field sizes in this approach is about 0·83% for Sp. For TPR20,10 differences for field sizes 10 × 10 cm2 is 0·29% and for TMR in five field sizes, the average value is ~ 1·6%.
Conclusion: In conclusion, the BEAMnrc and DOSXYZnrc codes package have very good accuracy in calculating dose distribution for 6 MV photon beam and it can be considered as a promising method for patient dose calculations and also the Monte Carlo model of primus linear accelerator built in this study can be used as method to calculate the dose distribution for cancer patients.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
381
381
https://ijmp.mums.ac.ir/article_13045_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13045
Image Optimization and reduction of radiation dose in CT of the paranasal sinuses
Mohammad
Davoudi
MSc of Medical Radiation Engineering, Department of Medical Imaging Center, Babol, Iran
author
Ali
Shabestani Monfared
Professor of Medical Physics, Radiotherapy Physicist, Babolsar Oncology Hospital, Department of Medical Physics, Babol University of Medical Sciences, Babol, Iran.
author
Gholam
Reza Ataei
Radiological technology Department faculty of paramedical sciences, Babol University of Medical Science, Babol, Iran
author
Sara
Delfan
Medical Physics, Radiotherapy Physicist, Babolsar Oncology Hospital, Babolsar, Iran
author
Shiva
Shoubkolaei
Medical Physics, Radiotherapy Physicist, Babolsar Oncology Hospital, Babolsar, Iran
author
text
article
2018
eng
Introduction: Since demand for computed tomography (CT) examinations is growing, patients are exposed more frequently to ionizing radiation. To reduce the dose delivered to patients in each scan, CT technologists can change the image acquisition parameters. However, this reduces image quality. Present study aimed to optimize and reduce radiation dose in a CT of the paranasal sinuses while minimizing deterioration of image quality
Materials and Methods: We divided the patients into two study groups: Group A was scanned axially and coronally using default parameters, while Group B was scanned axially and coronally using new parameters. The patients’ organ doses were estimated using the ImpactDose calculator. The tube voltage, tube current, pitch, rotation time, and other parameters were then reduced and optimized. After reconstruction and analysis, all of the images were of good diagnostic quality in both groups
Results: Using the new parameters, good agreement was found between the direct and reconstructed images. The CT parameters were reduced by the following proportions: kVp— 16.6%, mA—75%, rotation time—20%, and mAs—80%. However, these reductions did not obscure any anatomical landmarks. These parameters reduced the CTDIw, CTDIvol and DLP by 88.2%, 91.3%, and 91.3% respectively.
Conclusion: In conclusion, the results suggest that the use of a Bone algorithm reduces the total amount of radiation used during CT of the sinuses. We recommend using these parameters in children, in the evaluation of facial trauma, and in emergency CT of the paranasal sinuses
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
382
382
https://ijmp.mums.ac.ir/article_13046_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13046
Strategy of computed tomography image optimization in cervical vertebra and neck soft tissue in emergency patients
Mohammad
Davoudi
Department of Medical Radiation Engineering, Central Tehran Branch, Islamic Azad University, Tehran
author
Gholam Reza
Ataei
Radiological technology department faculty of paramedical sciences, Babol University of Medical Science, Babol, Iran
author
Yasser
Davoudi
PhD of Biomedical Engineering, Department of Medical Engineering, Semnan University of Medical Sciences, Semnan, Iran
author
text
article
2018
eng
Introduction: Due to the use of ionizing radiation in the CT scan, optimal parameters should be used to reduce the risk of cancer in patients who are constantly exposed to X-rays. The aim of this study was to optimize the parameters used in CT scan of cervical vertebrae and neck soft tissue with minimal loss of image quality
Materials and Methods: In this study, the patients were divided into two groups. The first group consisted of patients scanned with Default parameters and the second group scanned with new parameters. The findings included cervical vertebra and soft tissue protocols. The ImpactDose program was used to estimate the organs doses. All the images shown good diagnostic quality and the doses of organs around them were significantly decreased
Results: Good agreement was found between the new images and the default parameters. There was no significant quality reduction in the optimized images. The decrease in radiation dose in soft tissue protocol is: kV16.66%, mA31.25%, pitch24.13, rotation time33.3%, and in the cervical vertebra is: kV16.66%, mA64.28%, pitch48.27%. Decrease of these parameters reduced CTDIw 80.97%, CTDIvol90% and DLP90.21% in the cervical vertebra protocol, as well as CTDIw75.47%, CTDIvol81.34% and DLP81.36% in the soft tissue protocol
Conclusion: The results obtained in this study can be used in neck CT scan protocols in soft tissue and cervical vertebra windows. Due to reduction in the dose of the target area and the organs surrounding, these protocols could be used to reduce the risk of cancer and emergency patients
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
383
383
https://ijmp.mums.ac.ir/article_13047_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13047
Assessment of Effect Technical Directional Bremsstrahlung Splitting (DBS) on Spectra and Parameters of Simulation with Monte carlo Method BEAMnrc Code (Study Monte Carlo)
Hamed
babapour
MSc of Medical Radiation Engineering, Department of Medical Imaging Center, Guilan Oncology center (GOC), Rasht, Iran
author
Gholam Reza
Ataei
Radiological technology Department faculty of paramedical sciences, Babol University of Medical Science, Babol, Iran
author
Mohammad
Davoudi
MSc of Medical Radiation Engineering, Department of Medical Imaging Center, Babol, Iran
author
text
article
2018
eng
Introduction: Previous studies have shown that a Monte Carlo method for the transportations photon beam in medical linear accelerator is a good way. Strip of simulation can be used to measure the dose distribution in phantoms and patients' body. EGSnrc Code is the only code written for use in the field of radiation therapy that has many subset codes that BEAMnrc code is an important one, in which transferred electrons and photons simulation takes place in the head of medical device. DBS technique (Directional Bremsstrahlung Splitting) is a technique that applies a braking radiation in collision. In this study will be discussed to evaluate the effect of this technique on simulation time and particle number of phase-space data and its effect on output spectrum photon beam (6MV) Siemens accelerator Primus model
Materials and Methods: : Beginning the geometry of accelerator was stimulated according to its specifications by using the appropriate combination code BEAMnrc. Scoring plane that get phase-space data, in parts of the device such as: target, it was determined the flattening filter by using BEAMDP program to extract their average energy and output spectra in these parts. Also the other side of the research, simulation parameters and output spectra were compared by changing the amount of DBS.
Results: Due to the importance of time in fast Mont Carlo, in the simulation with low history of DBS. Considering the time and quality of the spectrum, DBS can be useful.
Conclusion: The results show that by changing the number of DBS from 1 to 1000, the amount of simulation time (Elapsed Time) and CPU time and number of particles into phase- space file, respectively have been 7.1, 7 and 36.9 times.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
384
384
https://ijmp.mums.ac.ir/article_13048_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13048
Synthesized Gd2O3 nanoparticles as contrast agent
Mohammad Javad
Alizadeh
Assistant Professor, Department of Physics, Faculty of Basic Sciences, Noshirvani university of technology, Babol, Iran. kariminezhad@nit.ac.ir
author
Hasan
Kariminezhad
Assistant Professor, Department of Physics, Faculty of Basic Sciences, Noshirvani university of technology, Babol, Iran
author
Ali
Shabestani Monfared
Department of Biophysics and Biochemistry, Faculty of Medical Sciences, Babol Medical University, Babol, Iran
author
Amerolah
Mostafaadeh
Department of Immunology, School of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Hosein
Amani
Faculty of Chemical Engineering, Babol Noshirvani University of Technology, Babol, Iran
author
Mohammad
Davoudi
Department of Biophysics and Biochemistry, Faculty of Medical Sciences, Babol Medical University, Babol, Iran
author
text
article
2018
eng
Introduction:
Gd (III) ion has been known to be the best metal ion in the periodic table that can be used as a T1 MRI contrast agent. Gadolinium have 7 unpaired electrons and these electrons can make magnetic area. No other metal ions possess unpaired electron more than this. CAs based on the element Gd are classified as “positive”, by opposition to “negative” CAs. Nowadays, Gd (III) chelates is prevailing in clinical use because it can be generally used for all organ. Around 35% of all MRI exams occur with contrast agents, and Gd (III) complexes are by far the most widely used contrast agents in clinical practice. The presence of superparamagnetic iron oxide particles in a tissue significantly changes the local magnetic field. Therefore, the optimal conditions to achieve 1H Larmor resonance are very sensitively affected. Suspensions of USPIO and SPIO typically express R2/R1 larger than 2. Physical properties of this magnetic element nanostructure have not studied so much yet. In this paper we have synthesized nanoparticles of Gadolinium Oxide in Polyol method and we try to compare it with commercial MRI contrast agent. On the other hand, there are reports about the effects of hyperthermia through the applying of strong magnetic fields on iron oxide superparamagnetism nanostructures. Later this property was used to treat cancer.
Materials and Methods:
We use Gd(NO3)3.6H2O, DEG, PVP 1.300.000 and NaOH that prepared by Sigma Merck to synthesized nanoparticles. We have verified this structure using Transmission electron microscopy (TEM), Dynamic light scattering (DLS) and X-ray crystallography (XRD) tests. Also we use Hyperthermia to calculate the temperature rise in magnetic field. Then we study magnetic properties of these nanoparticles with VSM and MRI images and compare it with two conventional contrast agents: Dotarem and Gadovist.
Results:
The DLS and TEM results show a diameter of 5 nm for the particles, with homogenous distributions among the solution. The XRD pattern show that we have crystal of Gd2O3. However, VSM results show that the anisotropy of this nanoparticles is 5.4 ×10-3 (J/m3) and a superparamagnetic loop, this value means we could have better relaxation time compared to Dotarem and Gadovist in magnetic area. By calculate the values we could find the relaxation time of our nanoparticles are 100 time smaller than commercial contrast agents. Hyperthermia shows 14ᵒ temperature rise in 0.15 T magnetic area that it could be used in cancer treatment.
Conclusion:
At the end of paper, we put the same concentration of Dotarem, Gadovist and nanoparticles in MRI image. By the results that calculate in VSM we guess that the contrast of nanoparticles must be better than commercial contrast agents. The results show that the highest contrast among these three structures refers to nanostructures. These results were obtained based on Hydrogens relaxation. This can be the base of using this nanoparticles as a MRI contrast agent in future.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
385
385
https://ijmp.mums.ac.ir/article_13049_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13049
Brain metabolites Associated with Common Clinical Symptoms of multiple sclerosis patients Using MagneticResonance Imaging
Marzieh
Reshadatian
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Mohamad Javad
Tahmasebi Birgani
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Ali
Yadollahpour
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Shapour
Dahaz
Department of Anatomy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Nastaran
Majdinasab
Department of Neurology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Morteza
Tahmasebi
Department of Radiology, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction: Multiple Sclerosis (MS) is an auto-immune disease that involves central nervous system (CNS). Magnetic Resonance Spectroscopy (MRS) is an analytical non- invasive method for obtaining the pathologic data of disease and it brings biochemical information about studied tissue which can be helped in studying the reasons and development process of disease and it increases the sensitivity of diagnosing for physicians. This method especially in studying of brain’s disease had many advances. In present investigation it was trying to demonstrate the abilities of this method in studying and primary, differential diagnosing in the various different sub-groups of multiple sclerosis disease.
Materials and Methods: in this research 31 patients who affected to multiple sclerosis (12 women, 4 men) RRMS, (7 women, 8 men) PPMS, 15 health people as control group participated in the study. Proper imaging protocols and MRS protocol was done for each patient and two parts of patient’s brain, respectively. One step with VOI selection in plaque region and other step in a normal region of withe tissue of brain (NAWM). By using statically tests the comparison between metabolites rate was evaluated in three sub-groups of disease and also it was done a comparison between the rates of metabolites in two regions of NAWM and plaque. Thus, 15 health people as control group was tested with those protocol by MRS and brain’s metabolites compared with patients metabolites.
Results: the rate of Cr metabolite in NAWM region has meaningful differences of P=0.03 between two sub-groups of PPMS, RRMS. In PPMS subgroup the rate of NAA showed meaningful difference of P=0.026 between NAWM and the plaques. The ratio of Cr/NAA in tissue of the substance white brain is meaningfully more than this ratio in plaque related to PPMS (P=0.007) sub-group.
Conclusion: the results of this study demonstrated that with surveying the rate of Cr or Cr/NAA in MS plaque can be diagnosed patients in two RRMS and PPMS sub-groups from each other.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
386
386
https://ijmp.mums.ac.ir/article_13050_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13050
Evaluation of 226Ra activity concentration in market consuming food staples of Ramsar, Iran
M.
Gooniband Shooshtari
Department of Medical Physics and Biomedical Engineering, School of Medicin, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
M. R.
Deevband
Department of Medical Physics and Biomedical Engineering, School of Medicin, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
M. R.
Kardan
Nuclear Science and Technology Research Institute, Tehran, Iran.
author
N.
Fathabadi
Environmental Radiological Protection Division, National Radiation Protection Department, Iran Nuclear Regulatory Authority, Atomic Energy Organization of Iran (AEOI), Tehran, Iran.
author
A. A.
Salehi
Department of Energy Engineering, Sharif University of Technology, Tehran, Iran.
author
K.
Naddafi
Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER) Tehran University of Medical Sciences, Tehran, Iran.
Department of Environmental Health Engineering
author
M.
Yunesian
Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER) Tehran University of Medical Sciences, Tehran, Iran.
author
R.
Nabizadeh Nodehi
Center for Air Pollution Research (CAPR), Institute for Environmental Research (IER) Tehran University of Medical Sciences, Tehran, Iran.
author
M.
Karimi
Environmental Radiological Protection Division, National Radiation Protection Department, Iran Nuclear Regulatory Authority, Atomic Energy Organization of Iran (AEOI), Tehran, Iran.
author
S. S.
Hosseini
Environmental Radiological Protection Division, National Radiation Protection Department, Iran Nuclear Regulatory Authority, Atomic Energy Organization of Iran (AEOI), Tehran, Iran.
author
text
article
2018
eng
Introduction: Among High Level Natural Radiation Areas (HLNRAs) all over the world, the northern coastal city of Ramsar has been considered enormously important. People living in this area have been exposed by several sources, one of which could be foodstuff. However, many studies have been carried out to measure the environmental radioactivity in Ramsar, but no survey has been undertaken to measure concentrations in theall stapled consumed foods yet. This study was dedicated to determine 226Ra activity concentration in the daily diets of Ramsar residents as a probable exposure.
Materials and Methods: About 70 different market samples were collected during the four seasons based on the daily consumption patterns of residents which have the highest consumption and their availability in the seasons. In these samples, after washing and drying and pretreatment, the radionuclide was determined by a-spectrometry.
Results: The mean radioactivity concentration of 226Ra ranged between 7 ± 1 mBq Kg−1 wet weight in meat, and 318 ± 118 mBq Kg−1 for tea dry leaves. The 226Ra activity concentrations in collected samples varied from below the minimum detectable activity up to 530 ± 30 mBq Kg−1. The 226Ra activity concentrations compared with the reference values of UNSCEAR appear to be higher in milk, chicken and eggs and less in grain products, vegetables, fruits and fish products. These results indicate that no significant 226Ra contamination is present in market foodstuffs and provide reference values for the foodstuffs in Ramsar.
Conclusion: The results show that the existence of 226 Ra in a variety of amounts, depending on the location of the food cultivation, proving the fact that residents could be exposed daily by food consumption, which include foodstuff from local and markets. Of the total daily dietary 226 Ra exposure from market consuming foodstuffs for adults in Ramsar, the largest percentage was from wheat. The residents consuming wheat and manufacturing wheat products such as bread, pasta, porridge, crackers, biscuits, pancakes, pies, pastries, cakes, cookies, muffins, rolls, doughnuts, breakfast cereals and so on may receive an elevated dose in the diet. In conclusion, with regards to presence of ²²⁶Ra in foodstuffs it is necessary to monitor regularly the activity of ²²⁶Ra in foodstuffs including market and local foods.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
389
389
https://ijmp.mums.ac.ir/article_13051_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13051
An investigation into the photothermal effects of multi- functional gold coated Fe3O4 Nanoparticles in the presence of external magnetic field and NIR laser irradiation on model of melanoma cancer cell line B16F10 in C57BL/6 mice
S.
Pandesh
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
S.
Haghjooy Javanmard
Applied Physiology Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
author
A.
Shakeri-zadeh
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
P.
Shokrani
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
text
article
2018
eng
Introduction: Photothermal therapy using gold nanoshells is one of cancer therapy methods. Gold nanoshells generally consist of a silica core and a thin gold shell. Fe3O4@Au core-shell can be used for magnetic targeted therapy. The objective of this study was investigation of the photothermal effects of magnetically targeted Fe3O4@Au NPs and NIR laser irradiation on model of melanoma cancer. The effective parameters in photothermal therapy include nanoparticles concentration, laser power density, and laser exposure time. In this research the effects of these parameters on produced heat and its spatial distribution in tissue equivalent phantom during photothermal therapy was evaluated.
Materials and Methods: At the first, the thermal distribution in tissue equivalent phantom have been simulated. The optimum laser power density and exposure time determined and simulation result verified in tissue equivalent phantom using thermocouple thermometer model ST 8891E. Invivo studies was performed on 100 C57BL/6 mice. Fe3O4@Au NPs was injected veinously to tumor inoculated mice, and accumulated in tumor using an external magnet. Then the tumor region was irradiated by laser (808 nm, 2.5 W/cm2, 6 minutes). For evaluation of treatment efficiency, we used pathologic studies and tumor growth measurement. Moreover, the temperature of tumor region was measured using IR camera model 875-1i.
Results: Simulation predicted a maximum temperature elevation of 12.5 ºC for nanoparticles concentration of 7 × 109 NP/ml and laser power density of 3.5 W/cm2 and irradiation time 6 min. The maximum discrepancy between simulations and phantom measurements was 8.6%. on the basis of simulation results the optimum parameters for treatment was nanoparticles dose 1.5 mg/kg, laser power density 3.5 W/cm2 and irradiation time 6 min. 2 weeks after treatment the average tumor volume multiplication in control relative to treatment group, was 10 and this was significant (one-way ANOVA, p < 0/001). The difference in average percentages of necrosis in control and treatment group was significant too (Mann-Whitney, p = 0.029).
Conclusion: In this study melanoma tumor inoculated in mice was treated using magnetically targeted Fe3O4@Au nanoparticles (dose of 1.5 mg/kg) and laser exposure (power density = 2.5 W/cm2 and exposure time 6 min). The results showed that simulation can be a reliable technique for photothermal therapy treatment planning.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
390
390
https://ijmp.mums.ac.ir/article_13052_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13052
Linearity response characterization of Polystyrene/ Graphene oxide nanocomposite as real-time dosimeter for therapeutic purposes
Armin
Mosayebi
Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
author
Shahryar
Malekie
Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
author
Farhood
Ziaie
Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
author
Hamide
Daneshvar
Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran, Iran.
author
text
article
2018
eng
Introduction: In recent years, one of the emerging two dimensional (2D) carbon based nano- materials namely Graphene Oxide has been incorporated into polymeric matrices to enhance the electrical properties of the composites. The electrical conductivity of Graphene Oxide is excellently used in fabricating polymer-based sensors, energy-related systems, biotechnology, anti-statics, microwave absorbers, conductive coatings, and ionizing radiation dosimeters.
The objective of this experimental work is to evaluate the linearity response of Polystyrene/Graphene oxide (0.1 wt%) nanocomposite as real-time dosimeter for therapeutic purposes.
Materials and Methods: PS 1540 was supplied by Tabriz Petrochemical Company. Graphene oxide (GO) naopowder was prepared from US Nano Inc, and finally high purity toluene and DCM as the solvents were purchased from Merck Company. Solution processing has been used to prepare 0.1 wt% PS/GO nanocomposite for dosimetry purposes. A Picker-V9 60Co gamma-cell installed in the Secondary Standard Dosimetry Laboratory (SSDL) of Iran was used to irradiate the nanocomposite at various dose rates in the range of 98-159 mGy/min.
Results: From the SEM images of fractured surfaces of PS/GO nanocomposite, the nano size scale of GOs nanoparticles can be observed as 140 nm. The plot of photocurrent versus dose rate for 0.1 wt% PS/GO was investigated. Results showed that the linearity was obtained in the range of 98-159 mGy/min with R2=1. The I-V measurements of the nanocomposite in a constant dose rate of 75 mGy/min at the SSD=80 cm were exhibited, in which the response was linear within the ±1000 V with R2=0.99, and also repeatability was examined for each measurement with the standard deviation less than 1%.
Conclusion: In this experimental research, the linearity of Polystyrene/Graphene oxide nanocomposite as real-time dosimeter was carried out. Results showed that this nanocomposite exhibited a linear response in different dose rates ranging from 98-159 mGy/min that can be used as a real-time dosimeter utilized in therapeutic level.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
391
391
https://ijmp.mums.ac.ir/article_13053_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13053
Low intensity ultrasound mechanical index as a parameter affecting of ability of proliferation and collagene type 1 expression of cells
Zeinab
Hormozi-Moghaddam
Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Manijhe
Mokhtari-Dizaji
Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
author
Mohammad Ali
Nilforoshzade
skin and stem cells research center, Medical Sciences, Tehran University, Tehran, Iran
author
Mohsen
Bakhshande
Department of technolody of radiology, Faculty of medical sciences, Shahid Beheshti University, Tehran, Iran
author
text
article
2018
eng
Introduction: Mechanical index (MI) is used for quantifying acoustic cavitation and the relationship between acoustic pressure and the frequency. In this study, modeling of the MI was applied to provide treatment protocol and to understand the effective physical processes on reproducibility and gene expression of fibroblast cells. Skin damage can occur of burn, cuts, abrasions and ulcers to varying degrees of severity. Fibroblasts are the major cell type in connective tissue and are critical for tissue restoration and remodeling after injury. Therapeutic ultrasound is commonly used to enhance the repair of tissue injuries and reduce associated pain. It was noted that these effects required specific exposure conditions
. So in this study, MI of threshold 0.2 in water and heigher (0.4) and lower (0.1) than it were investigatrd on the proliferation and collagene type 1 expression of fibroblast.
Materials and Methods: The acoustic pressure and MI equations are modeled and solved to estimate optimal MI for 1MHz and 40 kHz frequencies. Radial and axial acoustic pressure distribution was extracted. mechanical index of 0.10, 0.20, 0.40 that were compared with control and sham groups in continuous mode. The mature guniea pig skin was cut into small pieces (1mm2) and explanted in Medium. fibroblast cells isolated and growed of the skin explant after 25 days. The proliferation was calculated as a ratio of optical density (OD) of cells in MTT assay and type1 collagene expression was quantified with real time PCR utilizing SYBR.
Results: The optical density(OD) of experimental groups was normalized to that of corresponding 80000 groups at the day of 5th. Increasing reproducibility in the group of 0.21 mechanical index had the maximum reproducible (0.62±0.05) compared to control group (0.38±0.03). Fold change of expreesion level of fibroblast cells in 0.2 mechanical index has been achieved 4.35 ±0.03 compared to the control group.
Conclusion: Low intensity ultrasound with 0.20 MI is more effective on the proliferation rate and type1 collagene of Fibroblast cells. This model provides proper treatment planning in vitro and in vivo by estimating the cavitation phenomenon. Finally, the effect of low intensity ultrasound based on MI in the best limit obtained and suggested to used in skin wound healing, cell therapy and transplant.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
392
392
https://ijmp.mums.ac.ir/article_13054_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13054
The Feasibility of Thyroid Treatment with 99mTc Radiopharmaceuticals and Stable Iodine as Contrast Agent Using MCNP Simulation Code
Mahsa
Noorvand
Department of Physics, Islamic Azad University-Central Tehran Branch (IAUCTB), Tehran, Iran.
author
Seyed Pezhman
Shirmardi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran, 09126864850, P_shirmardi@aut.ac.ir.
author
Mostafa
Erfani
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran, 09126864850, P_shirmardi@aut.ac.ir.
author
text
article
2018
eng
Introduction: Nowadays, radioisotopes have a lot of therapeutic and diagnostic applications in nuclear medicine. The technetium-99m radioisotope is widely used in the diagnostic field. The technetium-99m radioisotope is widely used in the diagnostic field. In this study, in order to increase the absorption dose in thyroid cancer cells, the radioactive drug technetium-99m which is gamma emitter has been used along with iodine precursor in the desired concentrations.
Materials and Methods: Using the MIRD method and the MCNP simulation code, the absorbed dose and the effective dose originating from the radioactive technetium-99m, has been calculated for thyroid with the stable iodine contrast in the concentrations of 5, 10 and 100 mg/ml, and without it. Regarding the concentration of stable iodine in the thyroid that increases its equivalent atomic number, when photon is encountered with thyroid cancer cells with high equivalent atomic number, it creates photonelectrons. These photoelectrons can effectively lead to DNA fractures and thus cause damage and kill cancer cells.
Results: Considering the activity of 185 MBq from the radiopharmaceutical technetium-99m and stable iodine contrast in the desired concentrations, the increase percentage of absorption dose in the thyroid in the presence of stable iodine with concentrations of 5, 10 and 100 mg/ml was 7.25, 7.77 and 15.5%, respectively.
Conclusion: The results of this study indicate that prescription of stable iodine contrast in different concentrations along with technetium-99m increases the absorption rate of the thyroid. Therefore, this technique can be used to treat thyroid tumors with technetium-99m which is a gamma-emitting agent.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
393
393
https://ijmp.mums.ac.ir/article_13055_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13055
Benchmarking of Monte Carlo model of 6 Mv photon beam produced by Siemens Oncor® linear accelerator: determination of initial electron beam parameters in comparison with measurement
Milad
Najafzadeh
Department of Radiology, faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandare- Abbas, Iran
author
Mahdieh
Afkhami Ardakani
Department of Radiology, faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandare- Abbas, Iran
author
Mohammad
Haghparast
Department of Radiology, faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandare- Abbas, Iran
author
Abolfzal
Nickfarjam
Medical Physics Department, faculty of medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Radiotherapy Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran;
author
Mojtaba
Hoseini-Ghahfarokhi
Department of Radiology and Nuclear Medicine, School of Para Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Daniel
Markel
Radiation Medicine Program, Princess Margaret Cancer Centre, University of Health Network
author
text
article
2018
eng
Introduction: The aim of this study was to investigate the initial electron beam parameters for Monte Carlo model of 6MV photon beam produced by Siemens Oncor® linear accelerator.
Materials and Methods: In this study, the EGSnrc Monte Carlo user codes BEAMnrc and DOSXYZnrc were used. The beamnrc code were used for modelling of a 6 MV photon beam produced by Siemens Oncor® linac’s head and DOSXYZnrc code utilized for calculating dose distributions in a virtual water phantom. The simulations were started for 10×10 cm2 and 40×40 cm2 field sizes. First the electron energy was changed to match percent depth dose curves of simulations with those of measurements. Second the beam width of primary electron source was tweaked to match between dose profile curves of simulation with those of measurement. For data comparison a 1-dimensional Gamma analyses were used with criteria of 3%/ 3mm using an inhouse-matlab script. The gamma analyses were performed while dose distributions of Monte Carlo and measurements were set as an evaluated and reference dose.
Results: The results of gamma analyses showed that for percent depth dose curves a passing rate of close to 100% evaluated points. Also for profile curves, the passing rates were above 95% of evaluated points. Therefore, all depth dose and dose profile curves were in good agreement. The agreements were found at
5.75 MeV primary electron and 0.35 cm beam width respectively.
Conclusion: The Monte Carlo model of 6 MV photon beam produced by Siemens Oncor® linear accelerator was accurately benchmarked using measured data. Since the profile curves of large field sizes are much more sensitive to the variations of beam width than small field size, it is recommended that for tuning process both field sizes are considered.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
394
394
https://ijmp.mums.ac.ir/article_13056_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13056
Estimate bowtie filter shape in PET/CT scan with TLD
Nematollah
Ahmadi Jeshvaghane
PhD candidate, Department of Nuclear Engineering, Faculty of Advanced Sciences & Technologies, University of Isfahan, Isfahan, Iran
author
Alireza
Karimian
Associate Professor, Department of Biomedical Engineering, University of Isfahan, Isfahan, Iran
author
Mahdi
Nasri Nasrabadi
Associate Professor, Department of Nuclear Engineering, Faculty of Advanced Sciences & Technologies, University of Isfahan, Isfahan, Iran, Tel.: + 98 31 3793 4222; Fax: + 98 31 3793 2342, mnnasrabadi@ast.ui.ac.ir
author
Arman
Rahmim
Associate Professor, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
author
text
article
2018
eng
Introduction: The CT machine utilizes a bowtie filter to shape the X-ray beam and remove lower energy photons. Configuration of this bowtie filter is complex and its geometry is often not available in detail. It causes the CT dose index (CTDI) be with the different values in measurement versus Monte Carlo simulation studies and other analytical calculations. It is important especially in dosimetry of internal organs. In this study, the bowtie filter shape is extracted by using Thermolumenecence dosimeters (TLDs).
Materials and Methods: In this work, the shape of the bowtie filter of the Biograph 6 PET/CT was derived by using 31 Thermolumenecence chips dosimeters (GR-200 series) made of LiF: Mg, Cu, and P were utilized. These chips calibrated by Cs-137 in SSDL organization and ECC (Element Correction Coefficient) of them by using TLD reader Harshaw-4000. Eventually, to evaluate the accuracy of the body bowtie filter shape as generated by TLDs, Monte Carlo simulation of CT was performed. 16 X-ray sources in various angles were used within the Monte Carlo code (MCNP-4C) to simulate the CT section of the PET-CT Biograph 6 system and to calculate dose. In the simulation code, absorbed dose was determined for CT scan with MeV/gram/source particle units and converted into absorbed dose with mGy/100 mAs units by conversion factor (CF).
Results: The relative difference (RD) between simulated and measured CTDI value for the PET/CT Siemens Biograph 6 at 80, 110 and 130kVp were 4.2, 2.9 and 2.3%, respectively.
Conclusion: In summarize The results showed that it is possible to determine the shape of the bowtie filter in PET/CT using an inexpensive TLDs with acceptable accuracy
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
395
395
https://ijmp.mums.ac.ir/article_13057_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13057
Physical characteristics of electron beam from conventional and beam shaper IOERT applicator: A comparison study
Nematollah
Heidarloo
Radiation Medicine Department, Shahid Beheshti University, Tehran, Iran
author
Hamid Reza
Baghani
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
author
Seyed Mahmoud Reza
Aghamiri
Radiation Medicine Department, Shahid Beheshti University, Tehran, Iran
author
text
article
2018
eng
Introduction: Intraoperative electron radiation therapy (IOERT) is one of the cancer treatment techniques that delivers high doses to tumor bed during surgery. IOERT can be performed by either conventional LINACs or dedicated IORT accelerators such as LIAC (Light Intraoperative Accelerator). Two types of applicators can be used with LIAC dedicated accelerator including conventional applicator and beam shaper one. Standard applicators are cylindrical ones which can produce circular fields. On the other hand, beam shaper applicator is able to produce various square and rectangular fields through dedicated shielding blades located at the distal end of applicator. The aim of this study is to compare the dosimetric parameters and physical characteristic of electron beam produced by these two different types of IOERT applicators through Monte Carlo simulation.
Materials and Methods: The LIAC head in conjunction with conventional cylindrical and beam shaper applicator were simulated by MCNPX Monte Carlo code. The validity of simulated models was evaluated through comparing the Monte Carlo Based data (including PDDs and TDPs) and ionometric measured ones for both conventional and beam shaper applicator at different energies. Then, the energy and angular distribution of electron beam at the distal end of mentioned applicators were calculated for different combinations of energy/field sizes and obtained physical characteristics were quantitatively compared.
Results: For both types of studied applicators, the mean electron energy increases with increment of electron field size at the same energy. For conventional cylindrical applicators, the variations of mean electron energy with increasing field sizes ranges from 4.48 to 4.57,
5.63 to 6.13, 6.61 to 7.44 and 7.25 to 8.35 at 6, 8 10 and 12 MeV, respectively. Also, with increasing the field size for beam shaper applicator, the mean electron energy varies from 4.47 to 4.86, 5.76 to 6.65, 6.67 to 8.10 and 7.27 to 9.06 at 6, 8 10 and 12 MeV, respectively. Increasing the electron energy at the same field size causes the increment of mean scattering angle of electron beam at the distal end of both applicators understudy. With increasing field size for conventional applicators, the mean scattering angle of electron beam varies from 5.98 to 7.24, 5.62 to 6.68, 5.75 to 6.43 and 5.98 to 6.29 at 6, 8 10 and 12s MeV, respectively. Variations of mean scattering angle with increasing field sizes for beam shaper applicator also ranges from 6.89 to 7.19, 6.23 to 6.39, 5.93 to 5.95 and 5.50 to 5.69 for 6, 8 10 and 12 MeV, respectively.
Conclusion: Based on the obtained results, it can be concluded that the physical characteristics of produced electrons by shaper applicator are different from those of conventional applicator. This fact can be mainly attributed to the presence of shielding blades in design of beam shaper applicator.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
396
396
https://ijmp.mums.ac.ir/article_13058_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13058
In-vitro study of Radioprotection Effects of Cerium Oxide Nanoparticles in Exposure to MRC-5 Fibroblastic Cell lines with 6MV Photon Beams Using MTT Assay
Nouraddin
Abdi Goushbolagh
Medical physics MSc, Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Akram
Astani
Microbiology PhD, Department of Microbiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
Mohammad hosein
Zare
Medical physics PhD, Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
text
article
2018
eng
Introduction: Recently Cerium oxide nanoparticles (CONPs) are being checked as interventional treatments in biological systems. The scavenging of free radicals by nanoparticles performance is the inhibition of Reactive Oxygen Species (ROS). Ionizing radiations can prevent the proliferation and differentiation of cells and even cause apoptosis. CONPs, as radioprotection, can protect the healthy tissues of people who receive radiotherapy, as well as radiation workers and others exposed to radiation. In this study MRC-5 and MCF-7 cell lines treated with the CONPs were exposed to 6 MV photon beams.
Materials and Methods: Characterization of CONPs was determined using transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and spectrophotometer. The non-toxic concentration of nanoceria was determined by MTT assay on MRC-5 and MCF- 7 cells. Then the cells were treated at 0, 5, 10, 30, 50, 70 μM in non-toxic concentrations of
nanoceria and exposed to 6MV photon beam radiation with dose of 10, 20, 40, 60, 80, 100 and 200 cGy. For this aim, a plexiglass phantom with dimension of 40 × 40 × 1 cm3 was built. Cell viability was determined 24 hours after incubation. Fluctuation of cell viability due to changes in the concentration of nanoceria was investigated among different groups with a confidence level of 0.05.
Results: Characterization of CONPs was determined using transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and spectrophotometer. The non-toxic concentration of nanoceria was determined by MTT assay on MRC-5 and MCF-7 cells. Then the cells were treated at 0, 5, 10, 30, 50, 70 μM in non-toxic concentrations of nanoceria and
exposed to 6MV photon beam radiation with dose of 10, 20, 40, 60, 80, 100 and 200 cGy. For this aim, a plexiglass phantom with dimension of 40 × 40 × 1 cm3 was built. Cell viability was determined 24 hours after incubation. Fluctuation of cell viability due to changes in the concentration of nanoceria was investigated among different groups with a confidence level of 0.05.
Conclusion: By using cerium oxide nanoparticles in targeted radiotherapy, it is possible to reduce the probability of deterministic and stochastic damage, such as secondary cancers after radiotherapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
397
397
https://ijmp.mums.ac.ir/article_13059_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13059
Optimization of condition for Cerium Oxide Nanoparticles dispersion as radioprotective agent in deionized water
Nouraddin
Abdi Goushbolagh
Medical physics MSc, Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Akram
Astani
Microbiology PhD, Department of Microbiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Mohammad hosein
Zare
Medical physics PhD, Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
author
text
article
2018
eng
Introduction: Cerium oxide nanoparticles (CONPs) are used as radiation protection agent in the in-vivo and in-vitro studies. The distribution stability of nano-suspension is one of the important factors during the studies. The aim of this study is optimization of condition for CONPs dispersion with sodium dodecyl sulfate (SDS-anionic surfactant) and tween 20 (nonionic surfactant) in deionized water.
Materials and Methods: CONPs were obseved under scanning electron microscopy (SEM), then the dimensions and structure were obtained. The chemical composition of nanoceria was determined using Energy Dispersive X-Ray spectroscopy (EDS) analysis. The UV-VIS absorption spectrum of nanoceria suspension in the presence of SDS and Tween 20 surfactants were recorded and maximum absorption wavelength was determined. The mean sustained concentration of nanoceria suspension with different weight percentages of SDS (0.05, 0.15, 0.25, 0.45 and 0.65 wt%) was determined using standard curve. To increase the stability of the suspension distribution, the sonication time with a constant weight percentage of SDS was increased and the mean concentration was determined and then it was compared with suspensions containing various weight percentages of SDS.
Results: According to the SEM images taken in this study, the shape of nanoceria was spherical approximately. EDS analysis determined that the CONPs consisting of cerium with
97.9 wt% and oxide with 2.1 wt% with a high percentage of confidence. The dimensions of nanoparticles were determined 29.3 nm. The UV-VIS maximum absorption of nanoceria suspension was recorded at 318 nm. The wavelength of maximum absorption was changed at the presence of tween 20. So it was removed from the study. The mean sustained concentration of nanoceria suspension with 0.45 wt% of SDS had a significant increase than the presence of 0.05, 0.15, and 0.25 wt% of SDS (P-value = 0.001). With an increase in the SDS weight percentage to 0.65%, a reverse effect was observed in the nano-suspension distribution. An increase of 5 hours of sonication time resulted in a significant increase in the mean sustained concentration of nanoceria suspension (P-value = 0.000).
Conclusion: An anionic surfactant SDS with an optimum weight percentage of 0.45wt% can be used to increase the stability of the nanoceria distribution. Also, increasing the sonication time for 5 hours can be a better alternative than increasing the weight percentage of anionic surfactant SDS to achieve a stable distribution.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
398
398
https://ijmp.mums.ac.ir/article_13060_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13060
Calculation of Neutron Dose Ratio of Heart, Lung and Liver due to breast cancer Proton Therapy using MCNPX code
Niloofar
Azadegan
Department of Nuclear Engineering, Technical College, Islamic Azad University, Science and Research Branch, Tehran, Iran.
author
Seyed Pezhman
Shirmardi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran.
author
Mahdi
Sadeghi
Medical Physics Department, School of Medicine, Iran University of Medical Sciences, P.O. Box 1455-6183, Tehran, Iran.
author
Dariush
Sardari
Department of Nuclear Engineering, Technical College, Islamic Azad University, Science and Research Branch, Tehran, Iran.
author
text
article
2018
eng
Introduction: The proton beam produced in particle accelerators has an appropriate therapeutic potential. In this research, proton therapy of breast cancer is simulated using the MCNPX code in a MIRD phantom, also the contribution of scattered neutron dose during the proton therapy were calculated for the Heart, Lung and Liver.
Materials and Methods: For simulation of the proton therapy, the code based on the Monte Carlo method is used. Many investigations on the proton therapy planning simulations have been carried out using MCNPX and the other codes. In this study, a spherical tumor with the same elemental composition of breast is located at its tissue with 1 cm in radius. Bragg peak is created in tumor of the breast, for the proton beam energy of 70 MeV. Bragg peak of the 70 MeV proton beam energy is precisely placed at the end of the tumor.
Results: The results show that the scattered neutron dose ratio in the tissues close to the breast such as heart (1.25E-3), lung (1.2E-3) and liver (9E-5) are negligible.
Conclusion: The MCNPX (a Monte carlo simulation code) is a multi-purpose code which can be used for calculation of absorbed doses in radiation therapy. As the results of the code show, the contribution of scattered neutron dose is negligible in breast proton therapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
400
400
https://ijmp.mums.ac.ir/article_13061_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13061
Design of Small Animal Computed Tomography Imaging for in vitro and in vivo Studies
Vahid
Lohrabian
Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Tehran, Iran
author
Farough
Mohammad Mamashi
Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Tehran, Iran
author
Ali Reza
Kamali-Asl
Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Tehran, Iran
author
Hosein
Arabi
Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211, Geneva, Switzerland
author
Hamid Reza
Hemmati
Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Tehran, Iran
author
Habib
Zaidi
Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, Netherlands
Department of Nuclear Medicine, University of Southern Denmark, 500 Odense, Denmark
author
text
article
2018
eng
Introduction: Mini Computed Tomography (mini-CT) was suggested in biomedical research to investigate tissues and small animals. We present designed and built a mini x-ray computed tomography (mini-CT) for small animals as well as industrial component imaging.
Materials and Methods: The system used in this study includes a X-ray tube 20kV to 160kV and a flat panel detector with a pixel size of 200µm×200µm. The tested specimens are stacked on a stable rotating system. Due to the ability to change the distance between tube and sample, as well as sample to detector, we can virtually control magnification and FOV. A magnification change will produce images with different spatial resolution. In this way, changing the FOV scanner can actually achieve different spatial resolutions
Results: In this scanner, the spatial resolution varies as a function of the system FOV where the FOV can be changed from 43 to 10 (by changing the source to object distance), thus improving the spatial resolution from 3.9 up to 14.4 cycle/mm, respectively.
Conclusion: The system designed in this research can be used as a scanner in pre-clinical and industrial research, due to the relationship between the FOV and the spatial resolution.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
401
401
https://ijmp.mums.ac.ir/article_13064_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13064
Determination of Dosimetric characteristics of a New 192Ir-PDR Brachytherapy Source According to AAPM TG- 43 Protocol using Monte Carlo simulation technique
Vahid
Lohrabian
Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Tehran, Iran
author
Ali Reza
Kamali-Asl
Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Tehran, Iran
author
Mohammad Reza
Javanshir
Nuclear Science Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
author
Nematollah
Heidarloo
Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Tehran, Iran
author
Hamid Reza
Hemmati
Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Tehran, Iran
author
text
article
2018
eng
Introduction: 192Ir is one of the important sources frequently used in brachytherapy. Up to now, a lot of commercial models of this source have been made which Ir-192 has been recently added to them. The aim of the present study is to determine the dosimetric parameters of this new source model based on the recommendations of TG-43(U1) protocol using Monte Carlo simulation technique.
Materials and Methods: The assessed parameters included dose rate constant, radial dose function, anisotropy function, and dose distribution around the source. Calculations were performed in water phantom using MCNP4C Monte Carlo code.
Results: The dose rate constant of this new source in water was 1.07+0.06 cGyh-1U-1 which was in a good agreement with the TLD measured data (1.13+0.07 cGyh- 1U-1).
Conclusion: The results of this study showed that the dosimetric characteristics of this new brachytherapy source are comparable with those of other commercially available sources. Furthermore, the simulated parameters were in accordance with the previously measured ones. This means that the Monte Carlo simulated dosimetric parameters could be employed to obtain the dose distribution around this new brachytherapy source based on TG-43(U1) protocol.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
402
402
https://ijmp.mums.ac.ir/article_13065_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13065
Assessment of patient entrance skin dose (ESD) and effective dose (ED) for the most common interventional radiological exams at Mazandaran hospital
seyed ali
rahimi
Iran
author
text
article
2018
eng
Introduction:
Nowadays we are witnessing an exponential application of interventional radiology
techniques in various communities as well as Iran. Radiological technique is regarded
as the 2nd contributing factor in increasing the amount of public doses in various
societies. So that related radiation protection organization has recommended
measuring patient doses resulted from such techniques. The aims of this study have been the measurement of skin entrance dose, effective dose and also calculating the
parameters required to estimate the effective dose of interventional radiology systems
to reduce patient doses during common diagnostic and therapeutic interventional
examinations at Mazandaran hospital.
Materials and methods:
After reviewing and analyzing interventional radiology examination data at an imaging
center of a Mazandaran hospital over a 12 month period, the five most commonly
interventional radiology examinations, including cholangiography, liver
chemoembolization, uterine fibroids embolization, bile duct stinting and brain
embolization was selected for dosimetry calculations. For each examination, 10
patients were selected and their skin dose was measured using thermoluminescent
dosimeters (TLDs). The effective doses resulting from these examinations were
calculated using computational software (PCXMC) based on Monte Carlo calculations in
an average human phantom.
Results
The average entrance skin dose measured for the patients cholangiography, liver
chemoembolization, uterine fibroids embolization, bile duct stinting and brain
embolization was 52, 139, 413, 263 and 594 mGy respectively. Effective dose resulted
from the above examinations were 2.9,13, 36, 17.2 and 12 mSv respectively.
Conclusion
As expected, the patient dose in interventional radiology exams varied a lot because it
depends on many factors including the type of medical imaging systems, complexity
interventional examination, experience and skill of the operator, and patient weight.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
405
405
https://ijmp.mums.ac.ir/article_13067_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13067
Assessment and Comparison of Homogeneity and Conformity Indexes in Step-and-Shoot, Compensator-Based Intensity Modulated Radiation Therapy (IMRT) and Three-Dimensional Conformal Radiation Therapy (3D CRT) in Prostate Cancer
Kaveh
Shirani Tak Abi
Kaveh Shirani Tak Abi, Medical Physicist of Sina Radiotherapy Oncology Department, Bu Ali Hospital, Tehran, Iran.
author
Hassan Ali
Nedaie
Hassan Ali Nedaie, Assistant Prof. of Medical Physics, Radiotherapy Oncology Department, Tehran University of Medical Sciences, Tehran, Iran.
author
Hussain
Gharaati
Hussain Gharaati, Prof. of Medical Physics, Radiotherapy Oncology Department, Tehran University of Medical Sciences, Tehran, Iran.
author
Hossein
Hassani
Hossein Hassani, M. Sc of Medical Radiation Engineering, Department of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
author
Marzieh
Salimi
Marzieh Salimi, PhD. Candidate of Medical Physics, Medical Physics and Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.
author
Reza
KhodaBakhshi
Reza KhodaBakhshi, Radiation Oncologist, Consultant and Executive Director of Sina Radiotherapy Oncology Department, Bu Ali Hospital, Tehran, Iran.
author
Farid
Nezhad Dadgar
Farid Nezhad Dadgar, Assistance Prof. of Radiation Oncology, Sina Radiotherapy Oncology Department, Bu Ali Hospital, Islamic Azad University, Medical College, Tehran, Iran.
author
Malihe
Rezaie Yazdi
Malihe Rezaie Yazdi, Medical physicist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
Maryam
Rezaie Yazdi
Maryam Rezaie Yazdi, Medical physicist of Iran Mehr Radiotherapy Oncology Department, Iran Mehr Hospital, Birjand, Iran.
author
text
article
2018
eng
Introduction: Intensity modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D CRT) are two treatment modalities in prostate cancer, which provide acceptable dose distribution in tumor region with sparing the surrounding normal tissues. IMRT is based on inverse planning optimization; in which, intensity of beams is modified by using multileaf collimators and also compensators with optimum shapes in step and shoot (SAS) and compensator-based method, respectively. Materials and Methods: Prescribed dose was 80 Gy for both IMRT procedures and 70 Gy for 3D CRT. Treatment plans of 15 prostate cancer candidates were compared to target the minimum dose, maximum dose, V 76 Gy (for IMRT plans) V 66.5 Gy (for 3D CRT), mean dose, conformity index (CI), and homogeneity index (HI). Results: Dose conformity in compensators-based IMRT was better than SAS and 3D CRT. The same outcome was also achieved for homogeneity index. The target coverage was achieved 95% of prescribed dose to 95% of planning target volume (PTV) in 3D CRT and 95% of prescribed dose to 98% of PTV in IMRT methods. IMRT increases maximum dose of tumor region, improves CI and HI of target volume, and also reduces dose of organs at risks. Conclusion: Results of this study showed that both IMRT methods provide better target coverage in comparison of 3D CRT. In SAS technique, maximum dose reduced compared with compensator-based IMRT while, in the later method, CI and HI improved; it must be mentioned that 3D CRT also had the acceptable HI and CI results. IMRT approaches represented better homogeneity and conformity over 3D CRT and in comparison of two IMRT methods, all acceptable results can be achieved in compensator IMRT.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
406
406
https://ijmp.mums.ac.ir/article_13068_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13068
Investigating the effects of different kernels used for CT image reconstruction on dose distributions in treatment planning of kidney cancer radiotherapy
Chegeni
Nahid
Ph. D, Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
Marziyeh
Tahmasbi
Ph. D, Department of Radiology Technology, Paramedicine Faculty, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
Mohammad Javad
Tahmasebi Birgani
Ph. D, Radiation Therapy and Medical Physics Department, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences
author
Elahe
Soroosh Fard
M.Sc student, Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
text
article
2018
eng
Introduction: The quality of CT images used for treatment planning of cancer patients is an important issue in accurate outlining of the tumor volume and organs at risk. Different
kernels in CT scanner systems are available for improving the image quality. Applying these
kernels on CT images will change the CT numbers and electron density of tissues,
consequently. Therefore, the aim of this study was to assess effects of different CT kernels on
Hounsfield unit variations, the related computed electron densities and the calculated dose
distributions in radiation treatment planning system.
Materials and Methods: The 16 slice Siemens CT scanner used in this work. The B30, B35, B41 and B50 kernels applied on abdomen CT images for a kidney cancer patient. The ISOgray
treatment planning system was used for radiation treatment planning and calculating dose
of 6MV photon beam energy. The dose volume histogram (DVH) of left kidney as target
volume and spinal cord as organ at risk were calculated.
Results: The B50 kernel, had the greatest effect on calculated CT numbers for considered
reference points relative to standard kernel B30, among the applied kernels for image
reconstruction (16-19 HU variations). The average of calculated percent dose in target
volume for 3 reference points obtained %99.19, %100.36T %99.89 and %100.87 for
standard kernel B30 and other B35, B41 and B50 kernels, respectively. Mean dose in DVH was
2.03 for B30 and 2.05 for other kernels.
Conclusion: The Hounsfield units of the selected reference points, in the target volume of
reconstructed CT images by various kernels had relatively high variations respect to B30
kernel. Despite these variations, electron density and consequently the average of calculated
percent dose in the target volume did not show considerable changes. Hence, it can be
concluded that the use of image reconstruction kernels to improve the quality of CT images
will help to determine the edges and outlines of tumors and organs at risk more precisely.
While, applying these kernels does not significantly affect the amount of calculated doses in
the treatment planning system
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
407
407
https://ijmp.mums.ac.ir/article_13069_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13069
The evaluation of change in attenuation coefficient of cerrobend block used for radiation protection of healthy tissues in megavoltage photon radiation therapy after multiple melting
Mohamad Javad
Tahmasebi Birgani
Radiation Therapy and Medical Physics Department, Golestan Hospital, Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammad Ali
Behrooz
Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Fatemeh
Maghsoodinia
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Fariba
Farhadi Birgani
Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction:
Protecting the vital organs in radiation therapy is one of the most important issues. Cerrobend alloy, the most common material used as the shield, is melted several times and used for different patients. In this study changes in attenuation coefficient of cerrobend due to melting was investigated.
Materials and Methods:
In melting furnace, cerrobend was melted up to nine times and irradiated by Varian accelerator at radiotherapy department of Golestan hospital and the dose was measured by CC-13 ionization chamber with and without cerrobend blocks. The attenuation coefficients of cerrobend blocks were measured for irradiation fields of 6 × 6 cm2 and 10×10 cm2 at the photon energies of 6 mv and 18mv and analyzed by statistical methods.
Results:
Results of regression analysis with P<0.05, indicated that there was a significant relationship between the attenuation coefficient and frequencies of cerrobend melting: the attenuation coefficient increases with the increasing frequency of cerrobend melting.
Conclusion:
Continuous increasing in the frequency of cerrobend melting leads to increase in the attenuation coefficient of cerrobend block, thus cerrobend blocks can be used for patients, safely.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
408
408
https://ijmp.mums.ac.ir/article_13070_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13070
Energy and field size dependence of a silicon diode designed for small-field dosimetry
Mehran
Yarahmadi
Department of Medical Physics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran
author
Sonja
Wegener
Department of Radiation Oncology, University of Wuurzburg, Josef-Schneider-Strasse 11, 97080 Wuurzburg, Germany
author
Otto A.
Sauer
Department of Radiation Oncology, University of Wuurzburg, Josef-Schneider-Strasse 11, 97080 Wuurzburg, Germany
author
text
article
2018
eng
Purpose: To investigate the energy dependence/spectral sensitivity of silicon diodes designed for small-field dosimetry and obtain response factors (RFs) for arbitrary photon spectra using Monte Carlo (MC) simulations.
Methods: The EGSnrc user-code DOSRZnrc was used to calculate the dose deposition in water and in the active volume of a stereotactic diode field detector (SFD). Then, the RFs of the SFD were calculated for several circular field sizes and energies at 5 cm depth in water. Several low-energy photon spectra (mean energy 55 to 200 keV), as well as Co-60 radiation (mean energy 1.25 MeV) and a 6 MV Elekta Synergy beam (mean energy 2.9 MeV), in 10×10 cm2 field size were used to validate the MC calculations, using a simple beam model. The RFs of the SFD detector for a 6 MV Elekta Synergy linac photon beam in different field sizes were calculated. These were also measured with EBT3 Gafchromic film and the SFD detector.
Results: For the reference field size, differences between measured and calculated RFs were less than 5% at mean energies below 1 MeV and less than 1% at energies above 1 MeV. The calculated RFs for a 6 MV Elekta Synergy linac photon beam as a function of different field sizes showed a good agreement between the measurements and previously reported results. This agreement was within 2% for all considered field sizes.
Conclusion: While at high photon energies, the change of response of the SFD is marginal, whereas it is extreme at low energies. Therefore, it is desirable to benchmark response calculations also in the low energy domain. Our results, with a simple beam model and geometry, indicate that a validation of the simulations by experimental results is achievable. The present work provides a comprehensive table that can be used to calculate SFD detector response factors depending on both, field size and photon energy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
409
409
https://ijmp.mums.ac.ir/article_13072_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13072
Evaluation of gene expression of MLH1 and MSH2 between inhabitants of High Background Radiation Areas in Ramsar, Iran
E.
Bakhtiari
Medical physics department, babol university of medical sciences, cellular and molecular biology research center
author
K.
Ebrahimnejad Gorji
Medical physics department, babol university of medical sciences, cellular and molecular biology research center
author
A.
Shabestani Monfared
Medical physics department, babol university of medical sciences, cellular and molecular biology research center
Babol university of Medical Sciences, Babol, Mazandaran, Iran Email: monfared_ali@yahoo.com
author
H.
Akhavan niaki
Genetics department, babol university of medical sciences
author
S.
Borzoueisileh
Medical physics department, babol university of medical sciences, cellular and molecular biology research center
author
M.
Kosari Monfared
Genetics department, babol university of medical sciences
author
text
article
2018
eng
Introduction:
Annual effective radiation dose from all natural sources is approximately about 2.4 mSv and contribution of unnatural or man-made sources is 0.8 mSv. In some places of Ramsar, radiation dose due to radon exposure is about 3700 Bqm -3 while according to US EPA instruction radon levels should be 200 Bq m-3. Amazingly, there is not a meaningful result in the studies about health indices and dose assessments in residents of Ramsar, Iran. Even though the inhabitants of Ramsar expose to high dose radiation and they have more chromosomal aberration than control group but studies' results about frequency of cancer was not significant statistically. DNA mismatch repair (MMR) is a really safe keeping system in all being kinds. An important task of MMR is to certify replication accuracy by correcting wrong bases and insertion-deletion mutations in a new synthesized DNA and is responsible for constancy of genome in both prokaryotes and eukaryotes.
Materials and Methods:
Radiation level and dose distribution was measured. Sample collection was done from two groups including inhabitants of high background radiation area and normal background radiation area. RNA was Extracted by tripure. Quatitative Real Time PCR was performed and GAPDH used for normalization of gene expression data.
Results and Conclusion:
For the first time, we observe the significant upregulation of MLH1 gene in HBRA (Talesh mahalleh) population, revealed triggering of MMR system in response to high dose of background radiation.
MLH1 overexpression show significant association with Talesh mahalleh people age: Higher expression in above 50 year cases, demonstrate adaptation occurred during life span of residents.
MLH1 overexpression level in both sexes is similar, but MSH2 expression is significantly higher in female residents of Talesh mahalleh.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
412
412
https://ijmp.mums.ac.ir/article_13071_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13071
Comparing different techniques of Post Axillary field in Breast Cancer Treatment
S.
Khoshkharam
Medical Physics department, Reza Radiation Oncology Center, Mashhad, Iran. E-mail:sekhoshkharam@yahoo.com telephone: 09153224195
author
T
Moshirian
Medical Physics department, Reza Radiation Oncology Center, Mashhad, Iran.
Medical Physics Department, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
F
Varshoei
Medical Physics department, Reza Radiation Oncology Center, Mashhad, Iran.
author
F
Homaei
Medical Physics department, Reza Radiation Oncology Center, Mashhad, Iran.
author
text
article
2018
eng
As we know breast cancer is the second death reason in Iran. One step of treatment process
is radiotherapy, which needs careful consideration of contouring and therapeutic techniques
Lung, thyroid, spinal cord, trachea and humerus are sensitive organs in breast cancer
radiation therapy. The most clinical studies recommended two ways for delivering 95
percent of dose to supraclavicular and axillary nodes, one of them is an anterior field with a
posterior axillary boost (AP-PAB) technique for the axillary lymph nodes and supraclavicular treatment and another one is an anterior to posterior parallel pair (AP-PA) technique, at
Reza Radiotherapy and Oncology Center in Mashhad an anterior to posterior parallel pair
(AP-PA) technique was used. The aim of this study is comparing and evaluating delivered
dose for all organs in these techniques.
The study population comprised breast cancer patient in Reza Radiation and Oncology
Center (2016). Prowess panther version 5.2 was used as a treatment planning software.
Plans for 20 breast cancer cases were done with (AP-PAB) technique and (AP-PA) technique.
In each techniques delivered dose was investigated for lung, spinal cord, humerus, thyroid,
trachea, supraclavicular lymph node, axillary lymph node and the hot spot. Organ at risk and
nodes delivered dose were compared.
By comparing two technique dose volume histogram for each breast cancer case, based on
the analysis of data collected by software SPSS (p value=0.7 for average dose at 30% of lung
volume, p value=0.2 for average dose at 95% of axillary lymph nodes volume, p value=0.8
for average dose at thyroid, p value=0.8 for average dose at humerus, p value=0.6 for average
dose at trachea, p value=0.5 for average of maximum dose at spinal cord and p value=0.08
for average dose at 95% of supraclavicular lymph nodes volume. According to the results
there is not significant difference between these techniques because p value is higher than
0.05 for all organs in the other hand average dose at 30% of lung volume is 2% lower in (AP-
PAB) technique, average dose at thyroid is 1% lower in (AP-PAB) technique, average dose at
trachea is 4% lower and average of maximum dose at spinal cord is 4% lower in (AP-PAB)
technique. Average dose at 95% of axillary lymph nodes volume is 0.9% higher in (AP-PAB)
technique also average dose at 95% of supraclavicular lymph nodes volume is 1.2% higher
and average dose at humerus is 1.7% lower in (AP-PA) technique. This study shows (AP-
PAB) technique is acceptable for patients with critical conditions (cases with high dose
constrain of organ at risk.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
413
413
https://ijmp.mums.ac.ir/article_13073_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13073
Breast dose in conventional and digital mamography
Jafar
Rezapour
Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Reza
Paydar
Department of Radiology, Faculty of Paramedicine, Iran University of Medical Sciences, Tehran, Iran.
author
Ahmad
Mostaar
Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: The amount of doses received in mammography is one of the biggest concerns in the world. According to some statistics, every 12 minutes a woman dies due to breast cancer. Mammography concerned to detect breast cancer at an early stage of the disease as well as for screening, however due to the risk of exposure, the increasingly and widespread use of mammography for breast cancer screening is a controversial subject. This research was done to compare the breast dose in the conventional and digital mammography devices that used in mammography centers in Tabriz city on 1395. Materials and Methods: This research is a descriptive study. In the first three mammograms, according to the instructions of the Atomic Energy Organization of Iran (AEOI) for quality control were tested. Information about 322 patients who for mammography went to four centers over four months were collected, then the values of average dose of mammary glands in the mammogram images as milli-Gray (mGy) were calculated and analyzed. Results: In the 4 clinics, the mean values of compressed tissue thickness in the conventional mammography device for CC and MLO were 4.01 ± 0.92 cm and 4.49 ± 1.63 cm and the dose values were 1.53 ± 0.58 mGy and 1.58 ± 0.59 mGy respectivel, P-value that received is 1. Also the mean values of compressed tissue thickness in digital mammography device for CC and MLO were 5.8 ± 1.00 cm and 6.30 ± 1.01 cm and the dose values 2.07 ± 0.71 mGy and 2.15 ± 0.69 mGy were obtained respectively and also p-value is received 0.925. Conclusion: According to this study, it seems that despite the benefits of digital mammography on the conventional mammography, digital mammography device has more average absorbed dose rather than conventional mammography device. Due to the higher absorbed dose, doing of regular quality control and dose reduction techniques are recommended in digital mammography.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
414
414
https://ijmp.mums.ac.ir/article_13074_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13074
Intermittent low dose irradiation enhances the effectiveness of radio-therapy for human breast adenocarcinoma cell line MDA–MB–231
Amir
Danyaei
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Halime
Mansoury Asl
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Ali
Teimoori
Department of Virology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Mohammadjavad
Tahmasbi
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Hashem
Khanbabaei
Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
text
article
2018
eng
Introduction:
Hormesis and adaptive responses are two important biological effects of low-dose ionizing radiation (LDIR) in organism and mammalian cell lines. Notably, LDIR generates distinct
biological effects in cancer cells from normal cells, e.g., it may affect the growth of cancer cells via the activation of certain cell signaling pathway, which does not exist in normal cells. Therefore, LDIR is considered as a promising assistant method of clinical cancer therapy.
Materials and Methods:
In order to investigate the intermittent LDIR effect on breast cancer, MDA–MB–231 cells were divided into four experimental groups. Group A, cells were irradiated in 10 fractions
with a dose of 30 mGy at each one. The time interval between two irradiations was 24h.
Group B, were cultured simultaneously for the same10 days and received a dose of 300 mGy
and subsequently a high dose of 2 Gy after 24h. Group C, accepted a single high dose of 2 Gy.
Group D was mock irradiation group as control. We examined cell proliferation activity using
MTT assay and PI-Annexin V kit to assay cell apoptosis after 24 hours of last irradiation dose
(2Gy). Also we used RT-PCR to examine the cell cycle arrest and apoptosis pathway. For this
purpose we examined p21 and cespase3 genes in this study.
Results:
The intermittent LDIR increased cell apoptosis up to 32.55% and in other groups, apoptosis
were 30.14%, 25.49% and 8.37% in single LDIR, HDIR and control group respectively. The
apoptosis percentages were markedly higher than in the intermittent LDIR groups (P<0.01).
Through the cell growth assays, we observed that 300 mGy intermittent LDIR significantly
increased the killing effect of radiotherapy (viability: 71.95%) (P<0.01). Although apoptosis
in intermittent LDIR was the highest (32.55%) in comparison with other groups, the
expression of caspase3 gene in this group was the lowest (1.42fold), 4.26fold and 5.2 fold in
single LDIR and HDIR respectively. On the other, the expression of p21 gene, which plays the
role of cell cycle arresting, was the lowest in intermittent LDIR group (1.21fold) which
suggests that low dose of radiation can reduce the expression of p21 gene and promotes cell
cycle in damaged cell and finally causes the death of cancer cells.
Conclusion:
Intermittent LDIR followed by HDIR are a novel strategy to improve radiotherapy efficiency
and could be combined with other therapeutic modalities for cancer treatments. Low dose
has a different mechanism for killing cancer cells, therefore, it has no killing effect
on normal cells.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
415
415
https://ijmp.mums.ac.ir/article_13075_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13075
Primary efforts to optimize image quality in chest direct digital radiography of pediatric patient (for the age group 0 to 1 and 1 to 5 years) with survey some effective parameters in image quality and patient dose
Behzad
Mohsenzadeh
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran
author
Fereshte
Rahmani
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran
author
Zeinab
Kaveh
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran
author
Khatereh
Shamsi
MSc in radiobiology Department of Medical Physics Babol University of Medical Sciences
author
Hamed
Bagheri
Radiation & wave research center Aja University of Medical Sciences
author
Mohammad Reza
Deevband
Department of Medical Physics and Biomedical engineering, Faculty of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran TEL: 09123044609, E-mail: mdeevband@sbmu.ac.ir
author
Leila
Azimi
Departeman of imaging, Velayat hospital, University of medical science, Qazvin, Iran
author
text
article
2018
eng
Introduction: This study, evaluate pediatric digital radiography. Due to the high rates of this test and the high sensitivity of children to ionizing radiation in comparison with adults, it is attempted to achieve near optimal conditions by reducing the dose and maintaining the image quality. The object of the study is to change the irradiation parameters such as kV and mA and change them to a point where the dose is as high as possible for improved image quality or image quality preservation.
Materials and Methods: Irradiation data from 50 children were collected for each of 2 age groups 0-1and 1-5 years old, and the mean values of voltage, current, and tube-to-table distance were obtained. To investigate Improving image quality as the dose reduced, a homogeneous phantom was constructed to produce an equivalent chest distribution with less than 5% accuracy. The Monte Carlo simulation and the equivalent human phantom ORNL were used to make this phantom. Then, with use of a digital radiographic system and dosimetric instruments that calculate the dose, the dose of homogeneous phantom was measured. Subsequently, irradiation parameters such as kV and current were changed to provide voltages higher than reference voltage and lower current flow rates than those referring to a dose lower than the reference dose, the choice of these conditions is due to the decrease in absorption dose. Finally, three parameters MTF, SNR and CNR are measured using the tools designed in this phantom.
Results: With the results obtained for three parameters of each of the two age groups, the result was that for the age group 0-1, the best selection for the voltage and current was 60 and 2.5, respectively, in which the dose reduced and image quality increased. For 1 -5 years the voltage 75 with a current range of 3.2 to 5 mAs was close to optimum.
Conclusion: This article has determined wide variations in radiation dose of x-ray examinations. Also, to Reduce patient dose and enhance image quality is suggested following solutions:
1- utilization of Automatic Exposure Control (Of course, it's not easy to use for children with small body)
2- Used additional filters such as copper: This filter by removing low-energy beam makes the beam harder, and photoelectric effect reduced, as a result, the patient dose is reduced.
The works that was done in this study: Improving the exposure parameter compared to dose reference extracted 50 images for each age group and as well as improved its image quality.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
416
416
https://ijmp.mums.ac.ir/article_13076_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13076
Effect of Hyperthermia on self-renewality of prostate cancer stem cells
Jila
Rajaee
PhD Medical Physics, Department of Radiation Sciences, School Allied of Medical, Iran University of Medical Sciences, P.O. Box: 1449614525, Tel: 02186704540, fax: 02188622533, zh.rajaee@gmail.com , rajaee.j@iums.ac.ir
author
Samideh
Khoei
Professor of Biophysics, Head of Medical Physics Department, Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, P.O. Box: 1449614525, Tel: 02188622647, fax: 02188622647, khoei.s@iums.ac.ir
author
Seied Rabi
Mahdavi
Associate Professor of Medical Physics, Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, P.O. Box: 1449614525, Iran, Tel: 02188622647, fax: 02188622647, mahdavi.sr@iums.ac.ir
author
Marzieh
Ebrahimi
Associate Professor of Immunology, Department of Stem Cells and Developmental Biology at Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran,
author
text
article
2018
eng
Introduction:
Prostate cancer (PCa) is the most prevalent malignant tumor in the male population worldwide and it is the second leading cause of cancer-related death in males. PCa is almost incurable due to the resistance of PCa to conventional treatments. Cancer stem cells (CSCs) theory suggests that a small subpopulation of cancer cells is responsible for tumor development, relapse and metastasis. This cells possess self-renewal and give rise to nontumorigenic progeny that make up the bulk of the tumor.
Materials and Methods:
DU145 cells were cultured in stem cell medium containing serum-free medium to generate floating spheres (prostatospheres) enriched cancer stem cells. Sphere formation is progressively used as a golden method for enriching stem cells.
Following monolayer and sphere culture, DU145 cells were treated with different doses of hyperthermia. Hyperthermia was applied at 43 °C for 0, 30, 60 and 90 min in a precision water bath with ± 0.1 C accuracy.
The survival and self-renewing of the cells were evaluated by colony formation assay (CFA) and Sphere formation assay (SFA). SFA is based on the self-renewing properties unique to CSCs. CFA is used as a measure of the proliferative potential of cells. The results were compared between monolayer and sphere cells.
Results:
The results show that in both monolayer and Sphere cultures, Survival Fraction (CFA) decreases with the increase of heating time. Prolonged hyperthermia can affect the survival. Results of Survival Fraction (CFA) in equal durations of hyperthermia treatment were not significantly different between monolayer cells and Sphere cells. For both cultures Survival Fraction (SFA) decrease with the increase of hyperthermia exposure time. Results of Survival Fraction (SFA) after 90 min of hyperthermia treatment were significantly different between monolayer cells and Sphere cells.
Conclusion:
Hyperthermia is a promising approach which is utilized alone or in combination with radiotherapy and/or chemotherapy for the treatment of a variety of tumors.
Due to the relative resistance of CSCs to therapy, determination and characterization of thermoresistance of CSCs in the prostate tumor is the key to develop more efficient therapeutic strategies.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
417
417
https://ijmp.mums.ac.ir/article_13077_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13077
Effect of Radiation on self-renewality of prostate cancer stem cells.
Jila
Rajaee
PhD Medical Physics, Department of Radiation Sciences, School Allied of Medical, Iran University of Medical Sciences, P.O. Box: 1449614525, Tel: 02186704540, fax: 02188622533, zh.rajaee@gmail.com , rajaee.j@iums.ac.ir
author
Samideh
Khoei
Professor of Biophysics, Head of Medical Physics Department, Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, P.O. Box: 1449614525, Tel: 02188622647, fax: 02188622647, khoei.s@iums.ac.ir
author
Seied Rabi
Mahdavi
Associate Professor of Medical Physics, Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, P.O. Box: 1449614525, Iran, Tel: 02188622647, fax: 02188622647, mahdavi.sr@iums.ac.ir
author
Marzieh
Ebrahimi
Associate Professor of Immunology, Department of Stem Cells and Developmental Biology at Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran,
author
text
article
2018
eng
Introduction:
CSCs have been identified in prostate cancer (PCa), one of the most diagnosed malignancies in men over the world, for which radiation resistance is a major problem in the treatment of advanced stages.
Cancer stem cells (CSCs) have the ability to self-renew and differentiate to give rise to heterogeneous phenotype of the tumor cells. It is believed that CSCs are involved in metastasis, recurrence and therapy resistance in various cancers. Recently CSCs have been identified in prostate cancer. In vitro one of the main properties used to enriched cancer stem cells is their capacity to form spheres in non-adherent culture conditions.
Materials and Methods:
Human prostate carcinoma cell line (DU145) were plated in serum-free suspension culture system allowed for tumorsphere forming that enriched cancer stem cells. To identify prostate CSCs in adherent cells and nonadherent sphere cells of prostate cancer cell lines, the expression of the CD133 and CD44 cell-surface markers were assessed by flowcytometry. To evaluate of different doses of radiation (electron 6 MeV) on the self-renewal and proliferation of the Du145, sphere-formation assay (SFA) and plating efficiency (colony formation assay (CFA)) were assessed. The results were comparing with the parental cells. SFA is based on the self-renewing properties unique to CSCs. CFA is used as a measure of the proliferative potential of cells.
Results:
The results show that both SF (CFA) and SF (SFA) declined with the increase of radiation dose in cells treated as monolayer or sphere culture. However, the extent of reduction in cells treated as monolayer culture was significantly higher compared to cells treated as spheroids, suggesting higher resistance of spheroids to radiation.
According to these results, tumorspheres from PCa showed more radioresistant than bulk of tumor.
Conclusion:
Due to the relative resistance of CSCs to radiotherapy, determination and characterization of radioresistance of CSCs in the prostate tumor is the key to develop more efficient therapeutic strategies.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
418
418
https://ijmp.mums.ac.ir/article_13078_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13078
Comparison of Absorbed Dose in Thyroid and Lens as Organs at Risk Between in vivo Dosimetry and 3-D Treatment Planning Calculation in Head and Neck Radiotherapy by Linac Beam
Shima
Majidi
Department of Radiation Oncology, Shohada-E Tajrish Hospital, Tehran, Iran
author
Seyed Rabie
Mahdavi
Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran
author
Farhad
Manouchehri
Nuclear Science and Technology Research Institute, Radiation Applications School, Tehran, Iran
author
Alireza
nikoofar
Department of Radiation Oncology, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: Critical organs and structures may receive significant amounts of irradiation even if they are not the target of radiotherapy or located outside the treatment field. Although the sensitive thyroid gland and lens are not directly the targets of treatment, they can be affected by irradiation during the treatment of tumours in head and neck region. The purpose of this project is to compare measured dose by TLD and calculated dose in 3Dtreatment planning system (3DTPS) in thyroid and lens as critical organs during radiation therapy for patients with head and neck cancers. It can be improved treatment planning process to reduce absorbed doses of critical organs and side effects in radiotherapy. Beside knowing the absorbed dose of critical organs can be estimate secondary cancer in these organs.
Materials and methods: In this study the absorbed dose of thyroid and lens in anthropomorphic phantom and also 20 patients suffering from tumors in head and neck region under treatment by linac (varian 2100), measured by thermoluminesencent dosimeter chips (TLD-100). The results compared to calculated doses in 3DTPS called CorePlan in ETAR algorithm and analyzed by SPSS 19 software in paired T-Test. The secondary cancer risk was calculated using data provided in National Council on Radiation Protection & Measurements (NCRP) 116.
Results: According to the measurements performed on phantom the results of average absorbed dose in nasopharynx field organs were as follows in order: thyroid 190.94 ± 3.8 cGy/F, lens 10.3 ± 0.8 cGy/F, by TLD, respectively, and 195.2 ± 5.3cGy/F, 10.7 ± 0.2 cGy/F calculated by 3DTPS. In larynx field the results were: thyroid 181.1 ± 2.6 cGy/F, lens 1.1cGy/F, measured by TLD, respectively, and 186.1 ± 33.7 cGy/F, 0 cGy/F, calculated by 3DTPS. According to the treatment planning performed on the patients the results of average absorbed dose were in thyroid 4253.16 ± 1013 cGy and in lens 253.58 ± 84.2 cGy. The measurement of average absorbed dose by TLD in lens was 238.67 ± 83.4 cGy. Results revealed the fatal cancer risk for thyroid was about 3.4%.
Conclusion: The results showed that there are no significant differences between 3DTPS calculation and TLD measurement in thyroid and lens organs. It can be used of 3DTPS to estimate the absorbed dose of these organs in head and neck cancers. This study showed that the thyroid received a dose near to the TD5/5 in reported by Emami et al, which encourages recommendation of thyroid function follow up after radiotherapy in head and neck cancers.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
419
419
https://ijmp.mums.ac.ir/article_13079_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13079
Enhancement of radio sensitization by gold-silica shell- core nanoparticle in MCF7 breast cancer cells
Ghazal
Darfarin
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
author
Roya
Salehi
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Department of Medical Nanotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical Science, Tabriz, Iran
author
Effat
Alizadeh
Department of Medical Biotechnology, Faculty of Advanced Medical Science, Tabriz University of Medical Sciences, Tabriz, Iran
author
Behnam
Nasiri motlagh
Tabriz Valiasr Hospital, Department of Radiation Oncology, Tabriz, Iran
author
Abolfazl
Akbarzad
Tuberculosis and Lung Disease Research Center of Tabriz, Tabriz University of Medical Sciences
Department of Chemical Engineering, Northeastern University, Boston, MA, USA
author
Alireza
Naseri
Faculty of Advanced Medical Sciences, Tabriz University of Medical Science, Tabriz, Iran
author
Alireza
Farajollahi
Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Department of Medical Physic, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Imam Reza University Hospital, Radiotherapy Department, Tabriz University of Medical sciences, Tabriz, Iran
author
text
article
2018
eng
Introduction: In the present study, we investigated the role of gold-silica shell-core nanoparticle in megavoltage irradiation of MCF7 breast cancer cells.
Materials and Methods: gold-silicon oxide shell-core nanoparticles (NPs) were obtained by conjugation of gold nanoparticle with amine or thiol functionalized silica nanoparticles (AuN@SiO2 and AuS@SiO2). The structure of each nanoparticle was fully characterized by FTIR and TEM. The NPs treated cells were irradiated by using 6 and 18 MV x-rays. MTT and Brdu assay, DAPI staining and cell cycle were used to evaluate efficiency of nanoparticle in radiation therapy.
Results: The average size of AuN@SiO2 and AuS@SiO2 NPs was 23.79±7.04 and 31.28±7.37 nm, respectively. The Brdu findings revealed significantly more death in AuN@SiO2 (amine) treated and exposed cells compared to AuS@SiO2 (thiol) treated cells. (p<0.05). Cell cycle study show that presence of NPs enhanced the effect of radiotherapy, in particular, highest destructive effects were observed at the radiation dose of 8 Gy using energy 18 MV.
Conclusion: It was concluded that our findings may open the possibilities for cooperative radiotherapy and gold-silica shell-core nanoparticle by increasing cytotoxicity in MCF7 cells and decreased side effect from single modality radiotherapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
420
420
https://ijmp.mums.ac.ir/article_13080_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13080
Relative brightness due to temperature changes with ultrasound image analysis during Radiofrequency ablation
Zeinab alsadat
Ahmadi
Ph.D. Student of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Iran
author
Manijeh
Mokhtari Dizaji
Professor of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Iran
author
Atusa
Montaseri
Master of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Iran.
author
text
article
2018
eng
Introduction: Diagnosis of primary and secondary cancers to treat patients with diffuse and malignant tumors is an important subject. The appropriate treatment will be eliminating primary and metastatic tumors. Radiofrequency ablation with localized heat induction in the target tissue causes irreversible cellular damage and tissue coagulation. Estimation of tissue temperature changes is carried out under the guidance of ultrasound system. In addition to parameters such as variation in attenuation coefficient, acoustic power, thermal expansion, and variation in sound speed, the brightness of the ultrasound image shows a clear change in temperature. The aim of this study was to change brightness of ultrasound images in order to evaluate the thermal variations of tissue by Radiofrequency method.
Materials and Methods: With the fixation of ultrasound probe on the target tissue, all transverse cross- sectional images are visible from tip of the Radiofrequency electrodes and thermal sensor. DICOM images were transferred to PC and analyzed with RADWORKS Diagnostic 5.1 software. In order to estimate brightness of images for every degree temperature variation, ROI was plotted in desired areas, and average brightness values in pixels were assessed as a parameter without unit. In ultrasonic image processing, Circular ROIs was placed on both sides of thermal sensor, dimensions of each window were 2000 pixels (size of each pixel 0.05mm). To evaluation relative brightness, increasing temperature from 22˚C to 70 ˚C and reducing the temperature from 70 to 30 ˚C on reference image (with 22 ˚C) was drawn.
Results: brightness value for each temperature was normalized to mean brightness of reference image and relative brightness variation was calculated. Results for each temperature were calculated as mean and standard deviation with descriptive analysis. Then, to verify the correlation between brightness and temperature variations, Pearson correlation analysis was performed with 95% confidence. As temperature rises, relative brightness parameter increased linearly (R> 0.99 and P<< 0.005) with cooling tissue, slop of brightness images decreased faster in linear phase of 22 to 50 ˚C (R> 0.98). During heating of the tissue at 22 ˚C until 60 ˚C for every 13 ˚C, relative brightness increased by 25%. Then temperature range from 60 to 63 ˚C was quickly achieved maximum value. In cooling stage, until the temperature reaches 30 ˚C, it continued with 25% steps per 7 ˚C reduction of temperature. At 35 -33 ˚C, it has reached -50% and -52% of the initial value.
Conclusion: In this study, not only brightness of Ultrasound images can be used as a qualitative measure of tissue thermal variations but also it can be provided as a quantitative map of brightness variation during Radiofrequency ablatio
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
421
421
https://ijmp.mums.ac.ir/article_13081_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13081
Change of Hemoglobin Concentration with nano particles can predict breast cancer using near infrared source?
Parinaz
Mehnati
Medical radiation sciences research group, Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Bahman
Alipour
Medical radiation sciences research group, Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
Roya
Salehi
Medical radiation sciences research group, Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
author
text
article
2018
eng
Introduction: Early detection and treatment of breast cancer may be helping to save the lives of patients. Many new techniques have been urban to detect breast cancer. One of them is the use of nano-particles for accuracy and early diagnosis after photo transfer. In this study, rod gold nano particles was used according their ability to change light source transfer intensity.
Material and methods: rod gold nano particles and bloods with 1, 2 and 4 hemoglobin concentrations used to simulate breast cancerous conditions. Nanoparticles with each concentrations of hemoglobin injected into the breast phantom including vessels and transmitted light intensity measured by power meter. Light source was near infrared at 635 wavelengths.
Results: The intensity of the passing lights from normal hemoglobin concentrations was 6.71μw but when measured in the cancerous breast, it declined to 5.59μw and 3.97μw, for twice and four times the concentration of Hb in without nanoparticle condition, respectively.
. When the nanoparticles were blended with hemoglobin concentrations The intensity of the passing lights were determined to be 3.42μw, 2.13μw, and 1.98μw, for, normal, twice and four times the concentration of Hb, respectively.
Conclusions: This study showed that addition of rod gold nano particles to different concentration of hemoglobin provides an effective variation on the near infra red transferring intensity. This study suggests that near-infrared light accompanied by gold nanoparticles has the potential for early breast cancer diagnosis
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
422
422
https://ijmp.mums.ac.ir/article_13082_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13082
In vivo evaluation of the combination effect of near- infrared laser and PLGA polymer containing 5- fluorouracil – loaded Nano-graphene oxide
Arezoo
Mohammadi Gazestani
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran;
author
Samideh
Khoei
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran;
Razi Drug Research Centre, Iran University of Medical Sciences, Tehran, Iran;
author
Sepideh
Khoee
Department of Polymer Chemistry, School of Sciences, University of Tehran, Tehran, Iran;
author
Soraya
Emamgholizadeh Minaei
Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran;
author
Manijeh
Motevalian
Razi Drug Research Centre, Iran University of Medical Sciences, Tehran, Iran;
Department of Pharmacology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction:
Recently, nanographene oxide (NGO) is proven to be as a great candidate for drug delivery, and phototherapies cancer. Photothermal sensitivity of NGO and its optical absorption in the NIR region lead to photothermal ablation of tumors. Nevertheless, the major drawback of GO is its toxicity in biological systems, To overcome this problem, nanoscale GO prepare with biocompatible coating such as poly (lactic-co-glycolic acid) (PLGA).
5-Fluorouracil (5-FU) was loaded onto the biodegradable polymers or graphene sheets to extend its lifetime. The GO–super paramagnetic iron oxide nanoparticle (GO–SPION) composite has attracted extensive attention because of its highly controlled optical and magnetic properties. In this content, GO- SPION was modified with a biocompatible polymer, PLGA, and are used as the carrier for loading and delivery of 5-FU with the aim to achieve highly efficient cancer chemotherapy and photothermal therapy with minimal side effects in vivo applications.
Materials and Methods:
Mouse colon cancer CT26 cells (3 × 106) in a 100 μL serum-free RMPI-1640 medium were injected subcutaneous onto the right flank of BALB /c mouse. The mice were randomly divided into nine treatment groups of five mice. And after treatment, tumor sizes were measured in different groups.
Results:
Our results showed that single injection of NGO-SPION-PLGA-5-Fu, magnetic drug delivery and 808 nm laser irradiation (0.8 W/cm2, 3 min), effectively suppress the growth of tumors compared with 5-fluorouracil alone (P < 0.01). Finally, hyperthermia in combined with chemotherapy have tumor growth inhibition about 87.92%.
Conclusion:
Taken together, our results indicate that 5-FU loaded NGO-SPION-PLGA nanoparticles had good anti-tumor activity against colon cancer xenografts.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
423
423
https://ijmp.mums.ac.ir/article_13112_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13112
Impact of region of interest size and location in Gafchromic film dosimetry
Neda
Gholizadeh Sendani
Department of Medical Radiation Engineering, University of Isfahan, Isfahan, Iran
author
Alireza
Karimian
Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota, USA
author
S.
Rabie Mahdavi
Department of Biomedical Engineering, University of Isfahan, Isfahan, Iran
author
Iraj
Jabari
Radiation Biology Research Center and Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota, USA
author
Clara
Ferreira
Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota, USA
author
Parham
Alaei
Department of Medical Radiation Engineering, University of Isfahan, Isfahan, Iran
author
text
article
2018
eng
Introduction:
Accurate film dosimetry requires careful consideration of sources of uncertainty. Some of the sources of uncertainty are dependent on the size and location of region of interest (ROI), especially in small fields. Avoiding the penumbra is often a reason for using a small ROI. In contrast, choosing very small ROIs may increase uncertainty due to the reduction of the sampling data. Using a dose profile as flat as possible for the ROI becomes more significant in small fields in which the flatness of profile is greatly affected by the penumbra. This study aims to evaluate dependency of measured dose on size and location of region of interest (ROI) in Gafchromic EBT3 film for small field dosimetry.
Materials and Methods:
Gafchromic EBT3 films were irradiated using the 6MV beam from a linear accelerator at 10 cm depth (100 cm SSD) of a solid water phantom for a range of field sizes of 6×6 to 100×100 mm2. For scanning, 48 bits RGB mode with a spatial resolution of 72 dpi was used. The red channel of ImageJ software was used for evaluation. The appropriate location of ROIs were found by two methods. First, the ROI was visually placed at the center of image. Second, the profile of pixel value versus distance was plotted and the center of profile was used. Each scanned film was read using both methods and for three ROI sizes (1, 2, and 4 mm). In every scan, the film was re-positioned in the center of scanner. This uncertainty was compared with scan-to-scan variability when using piece of glass on top of the film. A plastic scintillator, Exradin W1, was used as a reference dosimeter. To obtain doses from W1 scintillator, a calibrated ion chamber with the same setup as W1 was used.
Results:
Comparing the three ROI sizes using both methods showed that there is less than 2% difference from reference in output factor measurements for field sizes larger or equal to 10×10 mm2. For field sizes of 15×15 and 10×10 mm2, the smaller mean percentage differences were observed in profiled-ROI (4×4 mm2) and centered-ROI (4×4 mm2). For the field sizes of 8×8 and 6×6 mm2, the profiled-ROI (2×2 mm2) had smallest mean percentage difference, which was 0.88%. The scan to scan variability was less than 0.31%.
Conclusion:
The ROI size of 4×4 mm2 is appropriate for dose measurements in field sizes of 100×100 mm2 to 10×10 mm2, regardless of the method of finding location of ROI. In field sizes smaller than 10×10 mm2, finding location of the ROI by profile of pixel values increases the accuracy of measurement, and ROI size of 2×2 mm2 has the smallest difference from the reference dose measurements.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
424
424
https://ijmp.mums.ac.ir/article_13113_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13113
Exploratory analysis of using supervised machine learning in [18F] FDG PET/CT images to predict treatment response in patients with metastatic and recurrent Brest tumors
M.
Nejabat
Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
author
L.
Papp
Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
Center of Medical Physics and Biomedical Engineering, QIMP Group, Medical University of Vienna
author
L.
Monschein
Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
author
M.
Hacker
Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
author
T.
Beyer
Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
Center of Medical Physics and Biomedical Engineering, QIMP Group, Medical University of Vienna
author
A.
Leisser
Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
author
A.R.
Haug
Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Austria
author
text
article
2018
eng
Aim: Despite grate progress in treatments, breast cancer is still the most common invasive cancer and the most cause of cancer related death in women. Treatment could be improved and perhaps standardized if more reliable markers for tumour progression and poor prognosis could be developed. The aim of this study was to evaluate whether patient-based machine learning (ML) driven analysis of 2-deoxy-2-(18F) fluoro-D-glucose PET/CT ([18F] FDG-PET/CT) is feasible to predict for treatment response and overall survival (OS) in patients with ENT tumours. Materials and methods: In total 136 patients with the diagnosis of metastatic and recurrent breast cancer (ductal/Lobular), who had a positive [18F] FDG- PET/CT scan between 12/2008 and 12/2015 were included in this analysis. Up to five malignant lesions were delineated on the PET images using semi-automatic VOIs, which were summed up to one total tumour volume, followed by feature extraction. Clinical data such as age, tumour grade, OS, course of treatment, response and P53, HER2, ER (oestrogen receptor) and PR (progesterone receptor) status were collected. ML approaches were utilized to identify relevant textural features on PET/CT and patient features and their relative weights for survival and response prediction. The established models were validated in a Monte Carlo (MC) cross-validation scheme, as presented in Papp et al. The individual datasets for these ML executions was selected from the given MC subset by bootstrapping.
Results: Median OS was 20.0 months (range: 0-89 mo). 46 patients received chemotherapy (8 patients received surgical resection after chemotherpy), 34 resections, 37 radiations and 23 hormonotherapy; response rates were 21/46, 18/35, 15/37 and 9/23 for the four treatment groups respectively. A treatment-based subgroup analysis yielded the best results with sensitivity (SNS) of 0.76, specificity (SPC) of 0.68 and an area under the curve (AUC) of
0.72 predicting for response and SNS of 0.7, SPC of 0.8 and AUC of 0.8 predicting for tumour grade after chemotherapy. For the whole cohort prediction of OS, response and grade showed values of 0.8, 0.6 and 0.6, 0.5, 0.6 and 0.7, 0.6, 0.6 and 0.7 for SNS, SPC and AUC respectively. Conclusion: These results demonstrate that textural and joint fusion features from PET-CT obtained by supervised ML are a valuable option for predicting OS, response and tumour grade in breast tumours.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
425
425
https://ijmp.mums.ac.ir/article_13114_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13114
In vitro study of radiosensitization of PLGA-SPION nanoparticles loaded with Gemcitabine
Nima
Hamzian
Assistant Professor, Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Maryam
Hashemi
Assistant Professor, Nanotechnology Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Mahdi
Ghorbani
Assistant Professor, Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Mohammad
Ramezani
Professor, Pharmaceutical Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Mohammad Hossein
Bahreyni Toosi
Professor, Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
author
text
article
2018
eng
Introduction:
To increase the radiation therapy efficiency, two approaches have been employed which include increasing the dose delivery or modifying the biological response to ionizing radiation. This study aimed to modify the biological response to ionizing radiation by combination therapy using radio-sensitizer agent and anticancer drug.
Materials and Methods:
In order to achieve this aim, super paramagnetic iron oxide nanoparticles (SPIONs) were prepared and used simultaneously with gemcitabine (Gem) as a chemotherapeutic drug. These two agents were encapsulated simultaneously in PLGA to form multifunctional drug delivery system. The physicochemical characteristics of the nanoparticles including particle size distribution, morphology, encapsulation efficiency and in vitro release were studied. The dose enhancement ratio (DER) of gemcitabine hydrochloride as well as PLGA-Gem, PLGA- SPION and PLGA-SPION-Gem nanoparticles were calculated and compared in human breast cancer cell line (MCF-7).
Results:
The PLGA-SPION-Gem nanoparticles exhibited narrow size distribution with spherical shape. The hydrodynamic diameters of nanoparticles were between 170 to 180 nm. Gemcitabine and SPION encapsulation efficiency were between 13.2% to 16.1% and 48.2% to 50.1%, respectively. In vitro gemcitabine release kinetics study showed a controlled behavior. The dose enhancement ratio for Gem, PLGA-Gem, PLGA-SPION and PLGA-SPION- Gem was the highest at 1 Gy 60Co and were 1.04, 1.63, 2.34 and 3.18, respectively. The radio sensitization of PLGA-SPION-Gem nanoparticles indicated a more significant radio sensitization activity compared with either other nanoparticles or gemcitabine alone (p≤0.001).
Conclusion:
We have successfully developed a gemcitabine and SPION-loaded PLGA with multifunctional drug delivery system for radiosensitization in radiotherapy. Future work includes in-vivo investigation of radiosensitization and other application of these nanoparticles.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
426
426
https://ijmp.mums.ac.ir/article_13115_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13115
Pseudo-CT Generation from Magnetic Resonance Imaging by fuzzy look up table algorithm
Niloofar
Yousefi Moteghaed
Department of Biomedical Engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Ahmad
Mostaar
Department of Biomedical Engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
text
article
2018
eng
Introduction: Despite growing interest in the use of magnetic resonance imaging (MRI) in the external radiotherapy design process (RT), Computer Tomography (CT) remains a gold standard and is regarded as a basic imaging modality in radiotherapy. MRI shows the high contrast in soft tissues without any radiation exposure to patients. As a result, MRI is used in functional tissue structures with registration on the CT images. Unfortunately, this causes systematic errors during the registration of MRI and CT images. The purpose of this study is to investigate the possibility of removing the CT simulator images and replacing it with pseudo-CT images (which created by MRI images) for the electron density calculation in radiotherapy treatment planning.
Materials and Methods: The pseudo-CT images were generated for 10 randomly chosen patients with brain disease. Data consisted of image voxels chosen within the segmented area of the brain in both MRI and CT images. The relation between MRI intensity and electron density was derived from HU converted model by fuzzy look up table algorithm.
Results: It was found that the MRI intensity value is related to the HU value within different parts such as skull bone, sinus, and brain. The mean prediction errors of the conversion model are -0.53, -0.082, 0.0145HU in brain, skull and air regions respectively. The mean absolute errors are 19.40 , 50.53,1.22
Conclusion: The proposed method enables generation of pseudo-CT data for the different segmented part of the brain from MRI series with appropriate mean prediction errors.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
427
427
https://ijmp.mums.ac.ir/article_13116_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13116
Recent Advances in PET-MR Hybrid contrast agent
Ramin
Akbaripour
Student of Nuclear Medicine Technology, Student Research Committee, Kermanshah University of medical sciences, Kermanshah, Iran. Email: arman.aaa1376@gmail.com
author
Saleh
Salehi Zahabi
Assistant Professor in Medical Physics, Department of Radiology and Nuclear Medicine, Kermanshah University of medical sciences, Kermanshah, Iran. Email: Saleh.salehizahabi@kums.ac.ir
author
text
article
2018
eng
Introduction:
All of the Imaging modalities have advantages and disadvantages alone. So if we want to have the best and perfect image, combining these modalities produces something we desired. PET-MR images consist of morphologic and metabolic data. MRI and PET provide high spatial and contrast resolution and high sensitivity and molecular information respectively. Hybrid PET-MR devices need Hybrid contrast agent that can be used for both of modalities.
Materials and Methods:
Hybrid PET-MR contrast agents have several advantages in some cases imaging separately is used. For this purpose, unimodal approach method is underuse. In this method contrast agents for one of both techniques, given nonsimultaneously or simultaneously, are used to obtain multiparametric information. Other method is bimodal approach that A bimodal imaging agent is generated with the goal of providing an enhanced contrast agent for a specific purpose. the most logical use of this approach is to add a radionuclide component to an MR contrast agent, hence providing:
Better quantification (PET vs MR imaging), and
Better whole body detectability, for guiding high-resolution MR imaging.
Most used MR contrast agent is SPION. To produce hybrid contrast agents in this method, a dextran-coated SPION is binded to a chelator like DOTA or DTPA or something else and PET tracer which is mentioned and sometimes an antibody or a peptide or agent of other modalities of imaging.
Results:
These agents are therefore capable of monitoring physicochemical properties in vivo and detecting enzyme deficiency or disorders. One of the most important use of hybrid contrast agents are in oncology. Lymph node imaging, tumor neoangiogenesis imaging and diffusion- weighted imaging (DWI) involve in applications of contrast agents.
Conclusion:
The use of PET-MR hybrid contrast agents is spreading daily and many project in different fields are performing and developed in recent years. Hybrid contrast agents are the most part of Medical Imaging in future.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
429
429
https://ijmp.mums.ac.ir/article_13117_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13117
(SPION-PLGA) ±PEG nanoparticles loaded with Gemcitabine as a multifunctional nanoparticle for therapeutic and diagnostic applications
Nima
Hamzian
Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Mohammad
Ramezani
Pharmaceutical Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
author
Maryam
Hashemi
Nanotechnology Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
author
Mahdi
Ghorbani
Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Mohammad Hossein
Bahreyni Toosi
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
Abstract
The aim of this study was to develop a novel multifunctional nanoparticle, which encapsulates SPION and Gemcitabine in PLGA±PEG to form multifunctional drug delivery system. For this aim, super paramagnetic iron oxide nanoparticles (SPIONs) were synthesized and encapsulated simultaneously with Gemcitabine (Gem) in PLGA±PEG copolymers via W/O/W double emulsification method. Optimum size and encapsulation efficiency for radiosensitization, hyperthermia and diagnostic applications were considered and the preparation parameters were systematically investigated and physicochemical characteristics of optimized nanoparticle were studied. Then SPION-PLGA and PLGA-Gem nanoparticles were prepared with the same optimized parameters and the toxicity of these nanoparticles was compared with Gemcitabine in human breast cancer cell line (MCF-7). The optimum preparation parameters were obtained with Gem/polymer equal to 0.04, SPION/polymer equal to 0.8 and 1% sucrose per 20 mg of polymer. The hydrodynamic diameters of all nanoparticles were under 200 nm. Encapsulation efficiency was adjusted between 13.2% to 16.1% for Gemcitabine and 48.2% to 50.1% for SPION. In-vitro Gemcitabine release kinetics had controlled behavior. Enhancement ratios for PLGA-Gem and SPION-PLGA-Gem at concentration of nanoparticles equal to IC50 of Gemcitabine were
1.53 and 1.89 respectively. The statistical difference was significant (p-value=0.006 for SPION-PLGA-Gem and p-value=0.015 for PLGA-Gem compared with Gemcitabine). In conclusion, we have successfully developed a Gemcitabine loaded super paramagnetic PLGA- Iron Oxide multifunctional drag delivery system. Future work includes in-vitro and in-vivo investigation of radiosensitization and other application of these nanoparticles.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
431
431
https://ijmp.mums.ac.ir/article_13118_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13118
Study of multifunctional PLGA-SPION nanoparticles loaded with Gemcitabine as radiosensitizer
Nima
Hamzian
Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
author
Maryam
Hashemi
Nanotechnology Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Mahdi
Ghorbani
Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
author
Mohammad
Ramezani
Pharmaceutical Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran.
Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Mohammad Hossein
Bahreyni Toosi
Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
author
text
article
2018
eng
Abstract
This study aimed to modify the biological response of cells to ionizing radiation by combination therapy using radio-sensitizer agent and anticancer drug. Super paramagnetic iron oxide nanoparticles (SPIONs) were prepared and used with gemcitabine (Gem). These two agents were encapsulated simultaneously into poly (D, L-lactic-co-glycolic acid) (PLGA) to form multifunctional drug delivery system. The physicochemical characteristics of the nanoparticles (NPs) were studied. The dose enhancement ratio (DER) of various treatment groups was calculated and compared using human breast cancer cell line (MCF-7). The DER for PLGA-SPION-Gem was the highest at 1 Gy 60Co (3.18). Cumulative effect from simultaneous use of two radiosensitizer (Gem and SPIONs) was observed. Thus, we have successfully developed PLGA NPs loaded with gemcitabine and SPION as a radiosensitizer system which potentially could be used in radiotherapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
432
432
https://ijmp.mums.ac.ir/article_13119_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13119
The Investigation of Absorbed Dose in Gastroesophageal Reflax Imaging Procedure in Children and Neonates
Seyedeh fatemeh
Khatani
Department of Pediatrics, Ghaem Hospital, Mashhad University of Medical Sciences
author
Parviz
Parvaresh
Department of Physics, Payame Noor University, Mashhad
author
Zahra sadat
Esmati
Department of Physics, Payame Noor University, Mashhad
author
text
article
2018
eng
Introduction: Nuclear medicine techniques have been widely employed in the assessment of gastroesophageal dysfunction. Gastroesophageal reflux (GER) is a common, self-limited process in infants and children that usually resolves at 12 to 18 months of age. Clinical management of GER includes conservative treatment, thickened feedings, positional therapy and parental reassurance. On the other hand, GER disease (GERD) is a less common, more serious pathological process that is manifested by poor weight gain, signs of esophagitis and persistent respiratory symptoms that usually warrant medical management and diagnostic evaluation.
photon sources are used for many applications, especially in medicine imaging. Milk scan is used as a sensitive and accurate method for diagnosing GERD in children. The aim of this study is to estimate the amount of absorbed doses in the organs of the stomach, esophagus, and heart of children and infants, who suffer from GERD, using the nuclear imaging.
Materials and Methods: By using the computational phantoms of (ORNL) and the MCNPX code in the Monte Carlo method, the absorbed dose of the 99mTc source was calculated as for different age groups. In this test, a certain radiopharmaceutical, which is often Tc99m colloid sulfur, is mixed with the breast milk or milk powder and will be given to the child. After entering the stomach, this radiopharmaceutical will go to an area in the esophagus and will be detected and imaged using the gamma camera.
Results: Results from the gamma dosimeter calculation, in which stomach has the highest absorbed dose from photon radiation because this radiopharmaceutical has the maximum accumulation in this organ. it is noteworthy that all the results in this study haven't exceeded the recommended ICRP standards.
The obtained results revealed that the absorbed energy fraction in the organs of the esophagus and heart has an inverse relationship with the distance the source organ. The organ, which absorbs the most dose from gamma radiation is stomach and this is expected because we defined the organ in the calculation code as the radiation source. Our study also shows a correlation between the age of the patients investigated and the rate of their absorbed dose, older children showing a absorbed dose is decreased than younger children.
Conclusion: The major objective of the present study is to diagnose GERD, using the labeled colloid sulfur radiopharmaceutical with 99mTc, to take the maximum absorbed dose in the stomach and the minimum dose in the organs of the esophagus and heart to create the maximum of effect for imaging and the minimum of complications.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
433
433
https://ijmp.mums.ac.ir/article_13120_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13120
Determination of the Effect of Sono-Photo Dynamic Therapy by using dual frequency in the presence of Mesoporous Silica Nanoparticles Encapsulated Porphyrin in the Treatment of Adenocarcinoma
Tahereh
Khani
MSc. Student of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Hadi
Hassanzadeh
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Majid
Jadidi
Professor of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Shima
Moshfegh
MSc. Student of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Monireh
Hoseinzadeh
MSc. Student of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Sahar
Jafari
MSc. Student of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Shokoufeh
Souri
MSc. Student of medical physics, Department of Medical Physics, Semnan University of Medical Sciences, Semnan, Iran.
author
Shoka
Sharyari
BSc. Student of Radiology Department of Radiology, Semnan University of Medical Sciences, Semnan, Iran
author
Shima
saidi
BSc. Student of Radiology Department of Radiology, Semnan University of Medical Sciences, Semnan, Iran
author
text
article
2018
eng
Introduction:
Breast cancer is the most common cancer among women in the world and in Iran. Sono-
photodynamic therapy is a new modality for cancer treatment. In this method, a sensitizer that activates by ultrasound and light produces photochemical and synchochemical activities, thereby causing the toxicity and destruction of tumor cells. The use of dual frequency ultrasound in this therapeutic approach increases synchymic activity and as a result, increases the cellular toxicity. Nanoparticles can be used in the delivery system to eliminate the limitations of sensitizers and improve the efficacy of the treatment. This study
to survey the effect of sono-photodynamic therapy with hematoporphyrin-encapsulated
drug in mesoporous silica nanoparticles in the animal model of adenocarcinoma.
Materials and Methods:
After induction of breast tumor adenocarcinoma in inbred Balb/C mice and reaching the
appropriate tumor size (diameter of 7-10 mm), the mice were randomly divided into 6
groups of 6 including control group, sham, injection of the drug encapsulated in dose of 5
mg/kg, a laser radiation group with a wavelength 650 nm (150 mW), the group of sonication
at the frequency 1MHz (2 W/cm2) + 3 MHz (2 W/cm2) and the group of injection of the drug
encapsulated in dose of 5 mg/kg with sonication at the frequency 1MHz (2 W/cm2) + 3 MHz
(2 W/cm2) and with laser radiation. The treatment process in different groups was
evaluated by evaluating the size of the tumor. Data were analyzed using SPSS software
version 22 and ANOVA test.
Results:
For laser radiation group with the injection of the encapsulated drug and with sonication at
a frequency 1 MHz (2 W/cm2) + 3 MHz (2 W/cm2), the trend of relative changes in volume
was less than other groups, and also the IR parameter was significantly higher than other
groups.
Conclusion:
The results of the study indicate significant inhibitory growth in the laser with sonication
group of two frequencies in the presence of sensitizing hematoporphyrin encapsulated in
mesoporous silica nanoparticles compared to other groups. This synergy can be due to
increased sonochemical activity, resulting in increased toxicity and cell death.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
435
435
https://ijmp.mums.ac.ir/article_13125_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13125
Measure the concentration of radon in fresh milk and compare it with radon values in samples of pasteurized milk
Abbas
Imani Pourya
Nuclear Engineering, Kerman Graduate University of Advanced Technology , e-mail:AbbasImaniPourya@gmail.com
author
text
article
2018
eng
Radon is one of the most important radioactive gases.Radon emits alpha particles and ultimately,it can cause genetic disorders.There are many reports of carcinogenesis and its harmful effects.One way to get this gas into the body is by eating and drinking.In the meantime,milk is one of the most consuming foods that can be contaminated with radon.In this study, the concentration of radon gas was investigated in two samples of fresh milk in Mahan city in Kerman, and finally,it was compared with the amounts of radon in pasteurized milk.Radon detection was performed by Rad 7 and due to the sensitivity of Rad 7 and the probability of occurrence, only two samples were studied. The average radon concentration in ten samples of pasteurized milk was 105.32±64.89 Bq m-3, while radon concentration in two samples of fresh milk was 3350±422 Bq m-3 and 315±129 Bq m-3.The value of 315±129 Bq m-3can be due to device error,because studies indicate that radon in fresh milk should be much higher than 315±129 Bq m-3.Finally, it was observed that radon concentration in fresh milk is higher than that of radon in pasteurized milk.Because in the stages of transfer, boiling, pasteurization and packaging of milk, a large amount of radon in the milk comes out, the lower the concentration of radon gas, the lesser its effect on eating milk.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
436
436
https://ijmp.mums.ac.ir/article_13126_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13126
Feasibility of using Medical Imaging Interaction Toolkit in volumetric studies to accurate diagnosing of vascular emboli by Extended NURBS-based Cardiac-Torso phantom
SeiedehFatemeh
Ayatifard
Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
author
Mahnaz
Amini
Assistant Prof., Lung disease research center, Faculty of Medicine Mashhad university of Medicine Sciences, Mashhad, Iran.
author
Masoud
Pezeshkirad
Assistant Prof., Department of Radiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
author
Negar
Moro vatdar
Assistant Prof., of Community Medicine Imam Reza Clinical Research Units, Faculty of Medicine Mashhad University of Medical Sciences, Mashhad, Iran.
author
Jalil
Pirayesh Islamian
Associate Prof., Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
author
text
article
2018
eng
Introduction: Important complications of venous thromboembolism (VTE) are a longer hospital stay, readmission, recurrence of the emboli, complications of anticoagulant therapy and death in a sever condition. In present study, the volume measurement accuracy of the medical imaging interaction toolkit (MITK) software on determining VTE in computed tomography images was evaluated. Methods: Several VTEs, ranged from 0.1 to 20 mm, were simulated in the arteries of a XCAT Phantom. Then, the MITK software was used for localization and volume measurement of the produced VTEs on the images of the simulated phantom. Results: The scatter plot and correlation coefficient were showed a high correlation between the calculated emboli volume measures by MITK software with those designed in the XCAT Phantom (r=0.98; p<0.001), The differences of the calculated measures and the simulated clots were mostly related to the clot volumes less than 0.1 ml (mainly due to the inability of the software to measure the range), which may be clinically ignored. However, a difference of about 0.01 ml for the clot volumes greater than 0.1 ml was in acceptable range. Conclusion: MITK software may be used for volume measurement studies in medical diagnosis, also for VTE accurate measurement to achieve a more accurate diagnosis and to eliminate the need to onsite diagnosis by the imaging system due to MITK capability on running in a personal computer.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
438
438
https://ijmp.mums.ac.ir/article_13127_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13127
Effective dose assessment in body organs after injection of 131I-MIBG
Elham
mirmosayeb
Department of Nuclear Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Mehdi
Salehi Barough
Department of Nuclear Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
author
Seyed Pezhman
Shirmardi
Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran.
author
text
article
2018
eng
Introduction:
Development of a novel radiopharmaceutical needs assessment of its biological- distribution in animal models, most commonly mice prior to its common application.
This study describes the biodistribution and absorbed dose prediction 131I-MIBG in human organs after injection in mice.
Materials and Methods:
In this research, 131I-MIBG radiopharmaceutical was injected to mice. After 4, 12, 24, and 48 hours post injection, the mice sacrificed and its organs dissected and counted by well detector. Then with having the Injected dose per gram of organs, absorbed dose of organs was calculated by MCNP simulation code and MIRD methods.
Results:
The results showed that the intestine and thyroid organs absorbed the least and most dose after injection of 131I-MIBG in mice.
Conclusion:
Many studies have demonstrated the usefulness of using animal distribution as a model for absorbed dose estimations in humans. Radiation dosimetry for 131I-MIBG was estimated for humans based on the biodistribution data in normal mice. The obtained results by MIRD and MCNP had shown close results.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
440
440
https://ijmp.mums.ac.ir/article_13130_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13130
Pretreatment quality control of single isocenter half- beam treatment planning technique using an amorphous silicon electronic portal-imaging device (EPID)
Farzaneh
Allaveisi
Department of Medical Physics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Nasrin
Amini
Department of Radiation Therapy, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
text
article
2018
eng
Introduction: Electronic portal imaging devices (EPIDs) are fundamentally used for
instantaneous verification of the patient set‐up, block shape, and leaf positions during radiation therapy.
In radiotherapy, situations arise in which an inclined PTV must be treated mutually with adjacent nodal regions. This methodology is most widely used for matching tangential/lateral breast/head and neck fields to supraclavicular and axillary nodal fields. The single-isocenter half-beam technique (SIHB) is the commonly used technique for field matching in the three-dimensional radiation therapy (3DCRT) in which abutting fields asymmetrically with no divergence at the central axis are matched. Linear accelerator asymmetric jaw junctioning is used in single isocenter half-beam treatment planning (SIHB) technique. In practice, the major difficulty of the SIHB technique lies in creating the dose accuracy at the central axis and dose homogeneity in the abutting region of half beams with sufficient precision represents.
The aim of this work was to investigate the use of amorphous silicon EPIDs for pretreatment quality control of the SIHB-based treatment plans.
Materials and Methods: The zero jaw position was studied at the gantry angle of 0º. All measurements were made for 6, 10, and 15MV photon beams. The EPID used in this study was a CCD camera‐based iView EPID mounted to an Elekta synergy platform. The EPID has been calibrated to convert a grayscale EPID image into a two‐dimensional absolute dose distribution. In addition, calculations of the central field dose were performed at a fixed EPID distance of 157.5cm.
The double-exposure technique and EPID was used for measuring the junction doses for each asymmetric jaw. The junction dose was obtained as a function of jaw position.
Then, the EPID- based junction dose measurements were compared with radiographic film measurements of junction dose.
Results: The results, obtained for 6, 10, and 15MV photon beams, showed that there was an approximately linear relationship between doses and gap or overlap. Because of the non- water equivalent EPID scattering properties, there were a different in the junction doses measured with the EPID and film. A correction factor was obtained to convert the EPID measured junction dose to film measured equivalent.
Conclusions: The inaccurate abutting junction between the half beams results in under or overdose of the normal tissue between the two volumes. In the present study, we carried out a procedure for daily EPID-based quality assurance of the SIHB technique of treatment planning. The utilization of this method can be significant enough to warrant the accuracy and safety of the SIHB technique in clinical procedures.
Conclusion: our study showed that the aSi EPID can be used as a transit dosimeter. The technique to reconstruct the dose delivered in the patient is straightforward, reproducible, and rapid for repeated in vivo dose verification.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
441
441
https://ijmp.mums.ac.ir/article_13131_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13131
Investigating the effects of glaucomatous (POAG) damage on the mVEP parameters
Amir
Daniaee
Ph. D, Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
Ali
Kasiri
MD, Department of Ophthalmology, Ophthalmology Research Center, Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Seyed Mahmoud
Latifi
M. Sc, Department of Health School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
author
Parvin
Armiun
M. Sc, Department of Medical Physics, Ahvaz Jundishapur University of Medical Sciences: Ahvaz, Iran
author
text
article
2018
eng
Introduction:
Glaucoma is considered as a major cause of irreversible vision loss, worldwide. Glaucoma includes a diverse ophthalmopathies characterized by attenuating the neural and connective tissue segments and eventually progression of specific patterns of visual dysfunction. Currently, perimetry is known as the most accurate diagnostic method in glaucoma and its follow up. For all patients with visual field defects, automated perimeters, such as the Humphrey Field Analyzer (HFA), enable rapid screening. This technique suffers from some disadvantages. Electrodiagnosis could be considered as an optional method in ophthalmology. Two important aspects of this method are its functionality and objectivity. The main purpose of this study is to investigate the effects of glaucomatous damage on the mfVEP parameters of patients suffering from primary open angle glaucoma (POAG).
Materials and Methods: The study was conducted at the ophthalmology clinic of Imam Khomeini hospital of Ahvaz. 15 healthy subjects and 15 patients with POAG. In addition to routine ophthalmological examinations including visual acuity, anterior segment examination, posterior segment examination, intra-ocular pressure, mfVEP with electrophysiological system, Reti Port/Scan 21 and visual field test with automated Humphrey ZEISS HFA II 750i Perimeter were also performed. All patients were categorized as unilateral POAG. The MD and PSD in more involved eyes in POAG patients were -6.72 (SD= ± -5.61) and 5.6 (SD= ± 4.95), respectively. To obtain an mfVEP, the low- and high- frequency cut off of recording was amplified at 1 and 100 Hz. The sample rate was set at about 1020 times per second.
Results: In this study, visual field assessing using mfVEP was applied to diagnose glaucomatous damage and also to determine the correlation of the ΔmfVEP parameters with the Δglobal indices (MD and PSD) between the two eyes of each patient by three following approaches. In the first and the second methods, intersubject and intrasubject comparisions between Δglobal indices of the HFA in the interpolated visual fields and ΔmfVEP parameters were done and no correlations were found. In the third method, the correlation between the number of points in each sector of mfVEP with the Δamplitude and the Δlatency in each patient (> mean ± 2SD) was determined. Moreover, the correlation of those points with the Δglobal indices of patients was clarified. there was a strong correlation between the ∆MDs and the number of abnormal points with the ∆amplitudes more than 256 nV, in POAG subjects (n = 15, r = 0.802, p <0.05).
Conclusion: Comparing the monocular mfVEP responses from both eyes is an appropriate method to detect unilateral damage. Achievement of more development and making the mfVEP test more functional, can be a solution for early diagnosis in most of the eye diseases.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
442
442
https://ijmp.mums.ac.ir/article_13132_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13132
Comparison of forward intensity modulated radiation therapy and two field tangential wedged beam techniques in radiotherapy of breast cancer: dosimetric and radiobiologic study
Farzaneh
Allaveisi
Department of Medical Physics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Zeinab
Salehi
Department of Radiation Therapy, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Nasrin
Amini
Department of Radiation Therapy, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Safoora
Nikzad
Department of Medical Physics, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
author
text
article
2018
eng
Introduction: This study aims to compare the dose delivery parameters and radiobiologic model prediction of Tumor Control Probability (TCP) of the FIMRT technique compared with rectangular two tangential wedged fields (2FW) in the treatment of breast cancer. Furthermore, reduction of the heart and lung dose in the FIMRT was studied via dosimetric parameters and radiobiologic model prediction of Normal Tissue Complication Probability (NTCP).
Materials and Methods: 25 left-sided breast cancer patients were selected. The planning target volume (PTV) and organs at risk (heart ad ipsilateral lung) were countered. The tangential technique of treatment planning consists of two optimized wedged beam (2FW) were compared to FIMRT plans for same patients.
The FIMRT and 2FW was planned for delivery of 50Gy dose to the target for 25 fractions. The minimum dose, maximum dose, mean dose and homogeneity index (HI) of the dose for the PTV were obtained for both techniques. Moreover, maximum and mean dose for the lung and heart tissues were obtained. The monitor unit (MUs) and the PTV97% were recorded.
Paired samples t-test was used for statistical analysis and p<0.05 was considered as significant level.
TCP and NTCP for radiation pneumonitis and late heart mortality was calculated with the Lyman model for organs at risk using dose-volume histogram (DVH).
Results: the homogeneity index between the two techniques was significant (p>0.05), HI=
1.32 vs 1.10 for 2FW and FIF, respectively. Mean dose to the breast PTV as mean±standard deviation value was 46.6±0.5 Gy for FIMRT vs. 46.8±1.3 Gy for 2FW plans.
The PTV97% was 92.5%± 3.2%, and 91.1%± 3.7 for the FIMRT and 2FW. The MUs of the 2FW plans and FIMRT plans were 326.4±11.2 and 212±10.3, respectively.
With the FIMRT, the mean dose of the heart and the lung was (2.9Gy vs. 1.9Gy) and (12.1Gy vs. 8.3Gy) respectively; the maximum doses in the heart and lung were decreased significantly from (3.5Gy to 2.1Gy) and (15.8Gy to 10.2Gy) in favor of the FIMRT plans.
TCP was 72.3% for FIMRT and 72.1% for 2FW plans.
The NTCP for radiation pneumonitis was (0.4%±0.1%) and (0.6%±0.5%) for the FIMRT and 2FW techniques, respectively. The NTCP for late heart was (6.1%±2.1%) for the 2FW technique. However, it was reduced to (3.8%±1.9%) in the FIMRT technique. Differences of the NTCP values were statistically significant for both lung and heart (p<0.05).
Conclusion: the treatment MUs were significantly reduced by the FIF-RT technique (p<0.05). For all organs, mean NTCP were lower for FIMRT than for the 2FW plans. The FIMRT delivered more homogenous dose to the target while maintaining or increasing the TCP. The FIMRT technique can be considered as a straightforward and fast technique to use clinically particularly in clinics that have not inverse IMRT.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
443
443
https://ijmp.mums.ac.ir/article_13134_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13134
Comparison between field-in-field technique and the use of conventional wedges for treatment planning of esophageal cancer
Farzaneh
Allaveisi
Department of Medical Physics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Nasrin
Amini
Department of Radiation Therapy, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Safoora
Nikzad
Department of Medical Physics, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
author
text
article
2018
eng
Introduction: This study was conducted to evaluate and quantify the treatment planning performance of MLC-optimized field-in-field planning technique (FIF), also named forward IMRT, versus wedge-based three field (W3F) technique in terms of dosimetric and radiobiological parameters for esophageal carcinoma.
Material and Methods: Twenty patients with esophageal cancer were selected. For each patient, two different treatment plans, one W3F and one FIF were created. The plans were delivered on an Elekta linear accelerator equipped with a 40 multi-leaf collimator. The quality and performance of the FIF plans were evaluated and compared with those of W3F plans regarding the conformity index (CI), homogeneity index (HI), mean dose (Dmean), maximum dose (Dmax), and tumor complication probability (TCP) for the planning target volume (PTV). Also, the parameters of the Dmean, and VxGy were used for evaluating the organs at risk (OARs) (including heart, lung, liver, and spinal cord). Moreover, the used monitor units per fraction (MU/fr) were compared between the two plans.
Results: A paired t-test statistical analysis did not show any significant differences (P>0.05) between the two treatment plans in terms of the Dmean, Dmax, CI, and HI parameters. The dose sparing parameters of the OARs including the lung V20Gy and Dmean of the liver and lungs were significantly reduced in the FIF plans compared with the W3F ones. Furthermore, the FIF technique indicated the advantage of significant decreasing the used MU/fr.
Conclusions: The FIF technique showed evident advantages regarding OAR sparing over the W3F technique for radiotherapy of the esophageal carcinoma patients. The FIF can be considered as a simple and easy-executable treatment planning technique in the clinical situations of esophageal malignancies, especially in clinics with no IMRT.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
444
444
https://ijmp.mums.ac.ir/article_13135_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13135
The Bystander Effects of Ultraviolet Radiation and Silver Nanoparticles on the H2AX gene expression in TK6 Cells
Zohreh
Eftekhari
Student research committee, Shiraz University of Medical Sciences, Shiraz, IRAN
Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, IRAN
author
Reza
Fardid
Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, IRAN
Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, IRAN
author
Abbas Behzad
Behbahani
Diagnostic Laboratory Sciences and Technology Research Center, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, IRAN
author
text
article
2018
eng
Introduction:
The radiation induced bystander effect (BSE) is the induction of biological changes in unexposed cells, by signals transmitted from bystander cells that cause the spread of radiation toxicity to adjacent or far tissues. In addition, reactive oxygen species (ROS) and reactive nitrogen species (RNS) such as cytokines are involved in mediating mechanisms in bystander effect through unknown factors. Bystander effects occur due to stressors, such as ionizing radiation, Ultra violet Radiation (UVR) and chemotherapy drugs, which include a wide range of biological processes, such as DNA damage, cell death, apoptosis, cell survival reduction, delayed and premature mutations, and Micronuclei formation.
Silver nanoparticles (Ag NPs) are widely used in electronics, bio-sensing, food industry, paints, sunscreens and medical devices. Due to the widespread use of these particles, the toxicological risks of Ag NPs must be determined for effective and safe use. The aim of this study was to investigate the possibility of increasing bystander effect on TK6 human lymphoblastoid cell line, which were exposed to UVC and Ag NPs.
Materials and Methods:
The studied groups included Control, UVR, Ag NPs, UVR+ Ag NPs, BSE of UVR, BSE of UVR + Ag NPs. TK6 cells were cultured in 24-well plates. After 24hrs Cells were exposed to Ag NPs (10μg/ml) for 1hr. Then they were exposed to UVR and after irradiation to determining the bystander effect, the irradiated cells medium was transferred to non-irradiated cells. Expression level of H2AX mRNAs were examined by relative quantitative real-time polymerase chain reaction (PCR).
Results:
The results showed that there was a significant difference in the mean expression level of H2AX genes of the UV group compared to the control group, control with Ag NPs, BSE of UV with BSE of UV + Ag Nps. There were not differences between control and BSE of UV. Conclusion:
Our findings demonstrate the gene expression of H2AX increased in UVR, Ag NPs, UVR + Ag NPs, groups significantly. In bystander groups UVR + Ag NPs decreased the H2AX gene expression in comparison to control group.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
445
445
https://ijmp.mums.ac.ir/article_13136_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13136
Advantages and disadvantages of removed flattening filter Linac: A Monte Carlo study on full quantitative dosimetric data of 18 MV-Varian Linac
Mansour
Zabihzadeh
Cancer, Environmental and Petroleum Pollutants Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Associate Professor, Department of Clinical Oncology, Faculty of Medicine, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
Seyed Rabee
Mahdavi
Associate Professor, Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran.
author
Mohammad Reza
Ay
Professor, Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
author
Mojtaba
Hoseini- Ghahfarokhi
PhD student, Department of Medical Physics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
author
text
article
2018
eng
Introduction: During intensity modulated radiation therapy (IMRT) technique, theoretically, presence of flattening filter (FF) across the beamline of clinical linear accelerator (linac) is not essential to obtain uniform lateral profiles due to intensity modulation of photon beams by multileaf collimators (MLCs). The aim of this study was to investigate the dosimetrical properties of 18 MV photon Beam-Varian linac with and without FF.
Materials and Methods: All dose measurements were performed on 18 MV, FF Mode-Varian 2100C/D linac. The FF and flattening filter free (FFF) modes of linac were modeled by MCNPX 2.4. code. The photon and contaminant electrons spectra, dose rate, present depth doses (PDD), lateral dose profiles, total and collimator scatter factors and out of field doses were calculated and compared with and without FF.
Results: Removing the FF increased the photon and contaminant electron fluences by factors of 5.48 and 3.94 for a 5 × 5 cm2 field size, respectively. The surface dose increased up to 155%. The flatness of dose profile was disturbed and deteriorated with increase of field size. Despite the dependence of the total scattering factor on field size, the variation of collimator scattering factors was neglected. The out-of-field dose decreased about 81.5 % for a 5 × 5 cm2 field size.
Conclusion: Removing FF from the linac’s head increases the dose rate and decreases the out-of-field dose, but the increased skin dose and deteriorated flatness of lateral dose profile are the main
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
446
446
https://ijmp.mums.ac.ir/article_13137_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13137
Metal Artifact Reduction of Dental Fillings in Head and Neck CT Images
Farahnaz
Rahimi
M.Sc. Student, Department of Medical Radiation Engineering, Shahid Beheshti University, G.C. Tehran, Iran, far.rahimi@sbu.ac.ir
author
Sanaz
Hariri Tabrizi
PhD, Department of Medical Radiation Engineering, Shahid Beheshti University, G.C. Tehran, Iran, S_HaririTabrizi@sbu.ac.ir
author
Zohreh
Azma
M.Sc. Department of Medical Radiation Engineering, Shahid Beheshti University, G.C. Tehran, Iran. zohreh.p2a@gmail.com
author
text
article
2018
eng
Introduction: The issue of metal artifact and its reduction is as old as the clinical use of computed tomography itself. When metal objects such as dental fillings, hip prostheses or surgical clips are present in the computed tomography (CT) field of view (FOV), make severe artifacts that reduce the image quality and accuracy of CT numbers. They can lead to unreliable clinical results due to inability in true tumor volume delineation and uncertainty in dose calculation of treatment planning software. So far, no generally accepted solution to this problem, especially for small size dental fillings, has been found. Herein, an approach is presented to reduce the dental filling artifacts in CT images of head and neck patients with multiple dental fillings. The proposed approach is compared with the commercial orthopedic metal artifact reduction (O-MAR) algorithm by Philips company.
Materials and Methods: Our algorithm consists of six steps: 1) metallic object segmentation by thresholding, 2) obtaining the prior image by multi thresholding of the initial image, 3) normalization of the original image sinogram by prior image, 4) interpolation (replacing the affected projection data by previous slice unaffected projection data, 5) denormalization of the corrected sinogram and 6) application of a two dimensional adaptive filter to the final image. The forth step can be implemented by substitution of affected projections with opposite view projections. Both methods were tested and previous slice substitution was superior. Quantitative evaluation of the commercial and proposed algorithms was done in terms of peak signal-to-noise ratio (PSNR), signal-to- noise ratio (SNR) and structural similarity index (SSIM) on a CT image of a head and neck patient with four dental fillings. The posterior part of the head in original image was considered as the reference image. Also two uniform regions of interest (ROI) were considered in the image. ROI1 was posterior region of the head away from dental fillings, while ROI2 was restricted to the tongue region near to the dental fillings.
Results: The PSNR, SNR, SSIM values obtained by the proposed method and O-MAR algorithm were 37.05, 36.13, 22.29, 21.37, 0.93 and 0.84, respectively. Using our approach, the standard deviation of CT numbers in ROI1 was 27 times less than the original image and 7% better than the commercial competitor. However, for ROI2 the commercial algorithm was 36% more successful in reduction of variations due to metal artifact.
Conclusion: The proposed approach can be applied successfully for dental filling artifact reduction in head and neck patients. Although the performance of the commercial method was superior to ours in near dental regions, for the farther regions with more critical organs was vice versa. However, weighting the interpolation and adaptive filtering steps may result in even better results.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
447
447
https://ijmp.mums.ac.ir/article_13138_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13138
Evaluation of the Observance of Radiation Protection Principles in Dentistry Centers in Kermanshah province (West Iran)
Mohammad Rasoul
Tohidnia
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Rasool
Azmoonfar
MSc of Radiobiology and Radiation Protection, Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Sogand
AbbasiAzizi
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Tahereh
Izadi
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
Fataneh
Aziz- zadeh
Radiology and Nuclear Medicine Department, Paramedical School, Kermanshah University of Medical Sciences, Kermanshah, Iran
author
text
article
2018
eng
Introduction:
Radiography plays an important role in the diagnosis of oral and dental disease and one of the most common diagnostic procedures in dentistry. Recent reports have raised concern about the increased use of ionizing radiation in dental imaging and the possibility of cancers. The effective dose of some dental radiographic examinations is high enough, so appropriate protective measures should be taken to reduce the dose of the patient. This study was designed to investigate the principles of radiation protection in dentistry centers.
Materials and Methods:
This cross-sectional study was design to assess level of radiation protection principles in dentistry centers. The radiology departments of 74 dentistry centers volunteers participated in this study. The data collection tool was a checklist that based on principles of radiation protection, which was used after verifying its content validity. Data were analyzed by SPSS 18 and the results were presented using descriptive statistics including mean and variance for quantitative and frequency variables and percentage for qualitative variables.
Results:
Based on the findings of this study, 75.7% of the centers were equipped with an intra-oral radiography. Despite observance principles of radiation protection for patient at dentistry center were in appropriate level (97. 3%), the observance of the protective principles was not adequate for the skilled workers in any center. Also, automatic processor for film processing wasn’t used at any of the centers and there was no systematic quality control program for radiographic devices. The most commonly used protective measure was the observance of a minimum distance of 2 meters from the patient (97.3%) during radiation. and the minimum protective measures, the use of high-speed film (1/4%), respectively.
Conclusion:
According to results in this study, the knowledge and practice of radiation protection are not satisfactory. Therefore, organizing retraining programs, equipped x-ray rooms with protection devices, Periodic monitoring of fully observance of safety regulations in these centers are recommended
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
448
448
https://ijmp.mums.ac.ir/article_13139_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13139
Integrating fMRI data into 3D conventional radiotherapy treatmentplanning of brain tumors
Arman
boroun
Department of medical physics, faculty of medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Shahrokh
Naseri
Medical physics research center, Mashhad University of Medical Sciences, Mashhad, Iran
author
Sirus
Nekooei
Associate Professor of Radiology, Mashhad University of Medical Sciences, Mashhad, Iran
author
Kazem
Anvari
Cancer Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Hossein
Akbari_Lalimi
Department of medical physics, faculty of medicine, Mashhad University of Medical Sciences, Mashhad, Iran
author
Jamshid
Jamali
Department of Biostatistics, faculty of Health, Mashhad University of Medical Sciences, Mashhad, Iran
author
Hamid
Gholamhosseinian
Medical physics research center, Mashhad University of Medical Sciences, Mashhad, Iran
author
Alireza
Montazer abadi
Medical physics research center, Mashhad University of Medical Sciences, Mashhad, Iran
author
text
article
2018
eng
Introduction: This study was aimed to investigate the beneficial effects of functional magnetic resonance imaging (fMRI) data in treatment planning for patients with CNS tumors in order to decrease the injury of functional regions of the brain followed by increase in life quality and survival of patients. This study pursues a novel approach in planning for the treatment of brain tumors in which using fMR imaging as a repeatable procedure, safe, and shorter scanning time functional regions of the brain are imaged and considered as organs at risk in radiation treatment planning. The present survey has been proposed for the first time in Iran and we hope that the obtained results will lead to increased quality of life.
Materials and Methods: In this study, 11 patients with brain tumor were enrolled. Prior to processing and analyzing of radiation treatment planning, computed tomography (CT), conventional MR, and fMR images were acquired from the patients. fMRI data were obtained using 1.5 T Siemens scanner. Initially, structural scans were acquired an axial T1- weighted MP-RAGE sequence for the localization of activation. fMRI scans were acquired using an echo planar imaging (EPI) sequence in the same position as the structural images. Employed tasks for each patient were determined considering the tumor location and extension in conventional MR images together with our knowledge in neuroanatomy. Owing to the higher risk of radiation damage in regions near to tumor, tumor-vicinity tasks were selected. fMRI data were processed via SPM software and functional active volumes were recognized. fMRI data and conventional MR images of T1W acquired in a same position were fused with one another and sent to the planning system. In order to investigate the potential benefits of integrating fMRI information in planning system, 3D conventional plans with and without fMRI data were compared using DVH analysis. All the active volumes were contoured as functional organs at risk (FOARs) in radiation treatment planning.
Results: Comparing the two plans it is expected to observe a significant dose decrease in functional regions while maintaining a similar coverage to the planning target volume and keeping structural organs at risk within accepted dose tolerance.
Conclusion: Precise combination of fMRI data in radiation treatment planning is expected not only to reduce radiation injury, but also to increase the cure rate for tumors by allowing delivery of a sufficient dose without fear of adverse reactions. Therefore, not only we have missed anything, but rather have prevented the critical regions from radiation damage which can lead to increased quality of life and life expectancy of patients.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
449
449
https://ijmp.mums.ac.ir/article_13140_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13140
Optimization of Bremsstrahlung imaging in Yttrium internal radiation therapy
Payvand
Taherparvar
Faculty of Science, University of Guilan, Rasht, Guilan, Email: p.taherparvar@guilan.ac.ir, Tell and Fax numbers: 01333323132
author
Nazila
Shahmari
Faculty of Science, University of Guilan, Rasht, Guilan, Email: nazila70.physic@gmail.com , Tell and Fax numbers: 01333323132
author
text
article
2018
eng
Introduction:
Treatment efficacy of radiation therapy using Yttrium-90 radionuclide is evaluated by the
bremsstrahlung SPECT imaging following radiation therapy. The radioisotopic images have the ability to provide reliable activity map of 90Y distribution. But these images have a low quantitative accuracy in the 90Y bremsstrahlung SPECT imaging, therefore the optimization of some imaging important indicators i.e. the energy window width and collimator
geometry, which heavily affect acquisition images quality, is necessary. The aim of this
paper is to estimate the effects of the energy window width and the hole diameter of a ME
collimator on the image contrast of the 90Y bremsstrahlung SPECT images obtained using
SIMIND Monte Carlo simulation program and improve image quality which could be used
to estimate activity distribution after radiation therapy.
Materials and Methods:
In this paper we simulated the SPECT system and a Jaszczak phantom consist of six hot
spheres in different diameters by use of the SIMIND Monte Carlo simulation program to
study 90Y SPECT images by assessment of the holes diameter of a ME collimator including
2.35, 2.59, 2.82, 2.94, 3.06 and 3.3 mm with fixed values of the collimator and septa
thicknesses (3.2 cm and 1.14mm, respectively) in the two energy windows including 60-
160 keV and 60-400 keV. SPECT imaging protocol is selected according to the clinical study.
An activity of 1.5GBq 90Y was considered for the hot spheres without background activity.
We used OS-EM algorithm to reconstruct projections and evaluated the contrast of the
reconstructed images of six hot spheres of Jaszczak phantom with selection of proper ROIs.
Results: The comparison of the images contrast of Jaszczak phantom spheres indicated that
generally with increasing the hole diameter of collimator, the images contrast of the
spheres were decreased. In order to, in comparison to the 1st energy window (60–160 keV),
the 2nd energy window (60-400 keV) was increased the image contrast. The results showed
that for a fixed collimator and septa thickness values (3.2 cm and 1.14mm, respectively),
the optimal value of the hole diameter was found 2.35 mm. Also from the stand point of the
image contrast, the optimal energy window was found ranging from 60 to 400 keV.
Conclusion:
By use of the evaluation of the images contrast of Jaszczak phantom by SIMIND Monte Carlo
simulation study, the best contrast is obtained when by use of the wide energy window
ranging from 60 to 400 keV, which increased the imaging system sensitivity and decreased
variance of the activity estimation. Moreover, a ME collimator with fixed values of 3.2 cm
and 1.14 mm for the collimator and septa thicknesses, respectively and a hole diameter of
2.35 mm can improve the 90Y activity estimation and provide a suitable image quality for
the 90Y bremsstrahlung SPECT imaging.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
450
450
https://ijmp.mums.ac.ir/article_13142_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13142
Positional changes in parotid glands during head and neck radiation therapy
Fahimeh
Rezaie
MSc in Medical Physics, Student Research Committee, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Karim
Khoshgard
Assistant Professor, Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
author
Abdolazim
Sedighi Pashaki
MD in Radiation Oncology, Department of Radiation Oncology, Mahdieh Radiotherapy Center, Hamadan, Iran. a.sedighipashaki@gmail.com
author
Mohammad Hadi
Gholami
Mahdieh Radiotherapy and Oncology charity center, Hamadan, Iran.
author
text
article
2018
eng
Introduction:
Xerostomia is the most common complication due to radiation–induced damage to salivary glands in head and neck cancer radiotherapy and it reduces quality of life. Parotid glands are main glands which they are account for secretion of stimulated saliva. Studies have demonstrated that mean tolerance parotid’s radiation dose under 26-30 Gy result in an increase in the number of patients who keep more than 25% of their initial stimulated saliva flow. But some studies have indicated that radiation in head and neck region causes positional changes in parotid glands. It may increase the parotid gland’s portion of radiation dose and consequently increases xerostomia complication. In this study radiation-induced positional changes in parotid glands are evaluated.
Materials and Methods:
In this study 10 head and neck cancer patients were studied. CT scan images obtained from them before and also after radiotherapy. Then position of parotid glands was evaluated by treatment planning software. In this purpose distance of parotid’s center of mass to radiopaque marker, located on patient’s mask, was measured. Then its radiation– induced positional changes were calculated.
Results:
In this study parotid mean dose was 4252±853 cGy. At this analyze at the end of radiotherapy, positional changes of parotid glands were observed.
Conclusion:
It seems that radiotherapy at head and neck regions may result in positional changes for parotid glands. Then there is probable that more portions of parotid glands involve in radiation fields and increase the damage to them. Therefore more attention to parotid glands, as an organ at risk, is necessary at planning treatment of head and neck cancers.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
451
451
https://ijmp.mums.ac.ir/article_13143_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13143
In vivo dose verification using using an amorphous silicon flat panel-type imager (a-Si EPIDs)
Farzaneh
Allaveisi
Department of Medical Physics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
Nasrin
Amini
Department of Radiation Therapy, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
author
text
article
2018
eng
Introduction: Electronic portal imaging devices (EPIDs) could be used to dose verification of radiotherapy treatment plans. In vivo dose verification is performed to reduce differences found between dose delivered to the patient and the prescribed dose. The aim of this study was to perform a fast and efficient technique for the verification of delivered dose to the patient using an a-Si EPID. To this end, the transit dose was measured using the EPID. Then, back projection of the portal dose images obtained during the treatment was performed to reconstruct the in vivo dose.
Materials and Methods: This study was performed using an amorphous silicon flat panel- type imager (a-Si EPIDs) (Elekta iViewGT) on an Elekta linear accelerator. EPID transit images were acquired for different high-energy open photon beams (i.e., 6, 10, and 15 MV). Then, the following procedure was used to derive the parameters of a formalism to reconstruct the dose in a single plane, intersecting the isocenter, perpendicular to the beam axis and parallel with the EPID detector plane.
The formalism is based on the conversion of the aSi EPID response to dose at the maximum depth in water. Moreover, the doses at the maximum depth in the absence of phantom as well as dose in the phantom at the point of interest are obtained by using the transit Tissue Maximum Ratio (TMR).
The ionization chamber located at the center of the EPID plane was used to measure the dose. Then, a comparison between the central axis doses of the EPID signal and ionization chamber measurements was performed.
In order to check the clinical implementation of the technique as well as the verification of patient plans, the protocol has been performed on 10 patients with prostate cancer treated with three dimensional conformal beams. For every patient, EPID images acquisition and measurement were made during the radiotherapy for seven successive fractions.
Results: The deviation between the ionization chamber and EPID signals in this study was in acceptable range (1 SD) which is consistent with the tolerance of the established studies. Furthermore, ratios between the prescribed dose planned by TPS and reconstructed dose from EPID measurements agreed well (mean±SD: 0.995±0.033).
Conclusion: our study showed that the aSi EPID can be used as a transit dosimeter. Furthermore, the applied method to reconstruct the dose delivered in the patient is straightforward, reproducible, and rapid for repeated in vivo dose verification.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
452
452
https://ijmp.mums.ac.ir/article_13145_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13145
The dosimetry assessment of Varian Linear Accelerators of 6, 15 and 20 MV by Monte Carlo Method
Ali
Rasouli
PhD student of nuclear physic, Faculty of physics, Shahrood University of Technology, Shahrood, Iran, arsalan.physics@gmail.com.
author
Hossein
Tavakoli-Anbaran
Associate professor, Faculty of physics, Shahrood University of Technology, Shahrood, Iran, tavakoli.Anbaran@gmail.com,
author
text
article
2018
eng
Introduction: Monte Carlo method is often applied in radiation therapy as utilized in all the branches of science. An important requirement for successful radiotherapy is carefully examine the dose distribution specifications and decrease the difference between these features with experience to an acceptable level. In this study, the characteristics of 6, 15 and 20 MeV incident x-rays are provided for 10×10 cm2 fields. This information is necessary to achieve an accurate treatment planning.
Materials and Methods: The MCNP code is employed to simulate 6 MeV photon beam from a major manufacturer of a Varian linac accelerator. The used phantom in this research was water. The output data charts have illustrated, by two software origin and table curve. Results: In order to validate the performance and accuracy of the simulated head, the parameters associated with 5×5 cm2 field were compared to empirical values. In this study, 6, 15, 20 MeV (6, 15, 20 photon modes) energy spectra, percentage depth dose, beam profile are calculated. The comparisons between calculated and experimental results show good agreement (with ±4%). Conclusion: The MCNP code has a suitable precision in calculation of dose distribution for these modes of Varian. There is a good agreement between empirical and simulation result for 6 MV photon beam for both percentage depth dose and beam profiles. For the next two modes, comparing results with references indicates that the results are acceptable as well as other applications in radiotherapy.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
453
453
https://ijmp.mums.ac.ir/article_13146_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13146
Comparison of different TBI techniques in terms of dose homogeneity
Elham
Hossein nezhad
MSc student of medical physic, Tehran university of medical sciences, Tehran, Iran. E-mail: elhamhoseinnezhad@gmail.com Tel:
+98 9178013685
author
Ghazale
Geraily
Phd of medical physic, Tehran university of medical sciences, Tehran, Iran
author
Mostafa
Farzin
Radiation oncologist, cancer Institute of Imam khomeini hospital, Tehran university of medical sciences, Tehran, Iran
author
Mahbod
Esfahani
MSc of medical physic, cancer Institute of Imam khomeini hospital, Tehran, Iran
author
text
article
2018
eng
Introduction: Total body irradiation (TBI) is a form of external beam radiotherapy which is used in conjunction with chemotherapy with the purpose of immunosuppression. Since the target in TBI is the whole body so a uniform dose distribution throughout the entire body during TBI is necessary. As recommended by AAPM dose variation must be within ±10% of prescription dose. A review was undertaken of clinical treatment techniques of TBI with purpose of assessment and comparison of dose distribution homogeneity in these methods.
Materials and Methods: This review article was conducted using PubMed, Science Direct and Google scholar. The articles were limited to megavoltage photon beams. Total marrow irradiation was excluded from the study.
Results: Numerous TBI techniques have been developed with the purpose of dose distribution homogeneity improvement. Some centers use opposed lateral fields and tissue compensators over thinner parts of the body to make homogeneity percent whitin10%. Compensators are usually made of lead, while, some centers use rice bags as compensators to make dose homogeneity within ±5%. Field-in-field technique is one of the recent methods that has been investigated by some departments. This technique dose not requires patient movement trough the treatment or secondary dose modulation equipment to make a homogeneous dose distribution. Arc therapy in a TBI technique that uses two generic arcs with rectangular segments to deliver TBI treatment dose with less than 3% dose deviation was also performed. Translational couch (TC) technique is the technique that uses translational couch to administer total body irradiation reproducibly and safely. This system can replace the stationary anterior-posterior technique for providing better dose uniformity within the patient compared to fixed beam techniques. Dynamic field technique is a method that does not require additional devices or complex processes to overcome the space limitations of small treatment rooms. This technique can deliver a uniform dose distribution to the body midline in a small treatment room while keeping the lung dose within the tolerance level. Techniques mentioned above are some of the various methods witch are being used to improve dose distribution homogeneity in total body irradiation.
Conclusion: Although with the evidences from literature there is limited substantiation to consider a treatment method better than others, but with regard to the size of the treatment room, workload of the radiotherapy department and prevalent technology used within each treatment department it is recommended to implement the suitable and optimum method in each department. However, when only compare the technique in terms of homogeneity percent the best techniques are FIF and Arc-therapy with almost ±3% homogeneity percent.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
454
454
https://ijmp.mums.ac.ir/article_13147_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13147
Evaluation of organs at risk dose in the left breast IOERT procedures whit and without shielding disc using monte carlo simulation
Ghazale
Mansorian
Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
Department of Radiation Sciences, School of Para medicine, Iran University of Medical Sciences, Tehran, Iran
author
Ali
Neshasteh-Riz
Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
author
Mostafa
Robatjazi
Department of Medical Physics and Radiological Sciences, Faculty of Medicine, Sabzevar University
author
Fereshteh
Koosha
Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
Department of Radiation Sciences, School of Para medicine, Iran University of Medical Sciences, Tehran, Iran
author
Reza
Paydar
Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
Department of Radiation Sciences, School of Para medicine, Iran University of Medical Sciences, Tehran, Iran
author
text
article
2018
eng
Introduction: One of the treatment choices in breast cancer is Intra operative electron beam radiation therapy (IOERT). Due to high dose delivery in this procedure, shielding disk is used to protect organs at risk (OARs). In this study, we evaluate the OARs dose in the breast IOERT using Monte Carlo simulation with and without shielding disk in RANDO phantom.
Material and Methods:
Simulation of dedicated IOERT linear accelerator (LIAC) head with 5cm diameter applicator was performed using BEAMnrc Monte Carlo simulation cod. Three phase-space files for each nominal electron beam energies (6,8,10,12 MeV) produced in the end of the applicator, after 2 cm tissue in the end of applicator. The last phase-space was created after disk. These phase- space were used in DOSXYZnrc for irradiation of RANDO phantom. Both lungs and heart were considered as OARs in the IOERT of the left breast irradiation. For each energy, the 3ddose files, as an output of DOSXYZnrc and contoured organs in the RANDO phantom imported to CERR software. 12Gy was considered as a normalized value in the target. Then dose-volume- histogram (DVH) data were extracted for analysis.
Results: The mean and maximum dose for each OAR in all energies with and without disk and with consideration of 2 cm tissue as a target were extracted from DVH data. For all nominal energies, the right lung dose was zero. The maximum and mean dose range in the left lung without disk were 11.5-13.9 and 0.15-0.5 Gy, respectively. These values for heart were 0-2.9 and 0-0.16Gy. The mean dose of heart and the left lung were un-remarkable with applying 2cm tissue and disk.
Conclusion: With the increase of the electron beam energy in the IOERT, an increase of OARs dose was seen with and without shielding disk application. On the other hand, application of shielding disk in breast IOERT reduces OARs dose significantly
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
456
456
https://ijmp.mums.ac.ir/article_13148_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13148
The protective effects of melatonin on blood cells of rectal cancer patients following radiation therapy; a randomized controlled trial
Nasim
Kouhi Habibi
Student Research Committee, Babol University of Medical Sciences, Babol, Iran
author
Ali
Shabestani Monfared
Cancer Research Center, Babol University of Medical Sciences, Babol, Iran
author
Kourosh
Ebrahimnejad Gorji
Department of Medical Physics Radiobiology and Radiation Protection, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
author
Masomeh
Karimi
Department of Radiation Therapy, Babol University of Medical Sciences, Babol, Iran
author
Ali Akbar
Moghadamnia
Department of Pharmacology, Babol University of Medical Sciences, Babol, Iran
author
Mehdi
Tourani
Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
author
Sajad
Borzoueisileh
Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
author
text
article
2018
eng
Introduction: Rectal cancer is a heterozygous disease in which cancerous cells grow in the rectum and lower parts of the colon. The primary cause of this cancer is not yet known, but factors such as over age 50, smoking, family history, improper diet or having a history of polyps and inflammatory bowel disease are the major risk factors for developing the rectum cancer. The rectum cancer symptoms are mainly characterized by rectal bleeding, but clinical signs such as fatigue, shortness of breath, anemia, bowel obstruction, weight loss, and dizziness may also be observed. Radiotherapy, chemotherapy, and surgery are the most common therapeutic approaches of rectal cancer. Almost all of the given therapies, such as radiotherapy could cause a declination in blood counts which could result in hematological disorders. Recent studies have demonstrated that administration of melatonin could reduce the adverse effects of radiation through activating and enhancement of the cellular anti- oxidant system in many animal models. In this study, we aimed to examine the radioprotective effects of melatonin on the blood cell counts of patients with rectum cancer undergoing radiotherapy.
Method and Material: This double-blind placebo-controlled study conducted on 60 rectal cancer patient referred to Rajaii Hospital of Babolsar, Iran. An equal number of patients were randomly assigned to the control group which received placebo and study group which received 20 mg melatonin a day as an intervention. The capsules of 20 mg melatonin were administered once a day for five days a week until 28 days at 45 minutes before radiotherapy, orally at 11 AM for 28 days. Blood samples were taken before melatonin receiving at day 1 and also day 28, then, to measure the changes in blood cell counts representing our primary outcomes, the samples were analyzed by Sysmex K810i auto- analyzer.
Result: The blood cells counted in both groups before and after administration of melatonin and placebo. The number of male and females was 20 and 10 respectively for both groups. The mean ages of participants were 53.58± 7.41. the blood cells count changes have been compared before and after receiving melatonin or the placebo. Our results showed that the platelet, white blood cells, lymphocyte and neutrophil population reduction induced by radiotherapy were slighter or even insignificant in melatonin recipients compared to control. However, the difference between red blood cells in both groups was not significant. Conclusion: This study is the first in vivo study in patients with rectal cancer that has been used melatonin as a radio-protector to reduce the harmful effects of treatment. Our results are indicating that melatonin could prevent or minimize the unfavorable effects of radiotherapy on blood cell count reductions by attenuating the adverse influence of radiation, probably through stimulation of cellular anti-oxidant potential as previously reported in animal models.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
457
457
https://ijmp.mums.ac.ir/article_13149_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13149
Evaluation of Iridium_192 radioisotope dosimeter calculations for vascular Brachiotherapy
Shima
Shekari
Azad islamic uni of Borujerd, medical radiation engineering department, Borujerd, Iran
author
text
article
2018
eng
Introduction:
One of the most effective means for treatment of coronary arteries cramp (CHD) is coronary intravascular Brachiotherapy. In this study, with use of MCNP code, in order to invastigating the score of ditribution of absorbed dose, drope in dose, and simulation mean, radiation doses around iridium_192 radioactive has been done.
Materials and Methods:
For this purpose, ORNL Fantum standard and human vessel has been chosen. In Fantum and simulation site, the rate of received dose from photon spring radiation with average energy about
0.38 Mg electron volt is well-performed.
Results:
Results show the importance of the amount of electron absorbed doses from photon interaction with a material in way of intravascular Brachiotherapy. This although shows that with the use of gama or photon, a great amount of dose will absorb in outside of vessel. This high amount in outside of vessel shows the importance of created electrons with use of interaction between photon and the material.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
458
458
https://ijmp.mums.ac.ir/article_13150_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13150
Investigation of dose distribution 252Cf Isotron brachytherapy source based on TG-43U1 protocol by Monte Carlo method
Ome Leila
Ahmadi
Ph. D Student of Nuclear Physics, Faculty of Physics and Nuclear Engineering, Shahrood University of Technology, Shahrood, Iran
author
Hossein
Tavakoli-Anbaran
Associate Professor, Faculty of Physics and Nuclear Engineering, Shahrood University of Technology, Shahrood, Iran Email: tavakoli-anbaran@shahroodut.ac.ir, Telephone: +982332395270 Fax numbers: +982332395270
author
text
article
2018
eng
Introduction:The commercial 252Cf sources are too large in size and clinical applications of neutronbrachytherapy (NBT) are limited to a small number of intracavitary treatments of cervical cancers. Recently, under the Cooperative Research and Development Agreement (CRADA) with Isotron Inc., the Oak Ridge National Laboratory (ORNL) encapsulated a new medical 252Cf sources, called Isotron sources that used to intracavitary and interstitial brachytherapy. On the other hand, prior to the clinical application of brachytherapy sources, their dose distributions should be investigated. In this study, Monte Carlo calculations of dose distribution the 252Cf Isotron source is done in the water phantom.
Materials and Methods:
Dose distributions parameters based on TG-43U1 protocol are radial dose function and anisotropy function. Physical and geometrical parameters of the 252Cf source were simulated by MCNPX (2.6.0) code based on TG-43U1 protocol in the water medium. To estimate the dose rate distribution in water, the source was situated in the center of a spherical 20 cm radius water phantom. The Radial dose function was determined in water, in a cylindrical annulus 0.2 mm × 0.2mm deep positioned along the transverse axis at distances ranging from 0.5 to 10 cm from the source center. The neutron absorbed doses in water were calculated using F6 tallies. Anisotropy functions were calculated at intervals of 1, 2, 3, 4, 5, 10 cm and at different polar angles from θ=0º to 90º with respect to the source long axis in the water phantom.
Results:
Statistical uncertainty for neutron absorbed dose rates at r ≤ 3.5 cm are lower than 0.3%, and at 4-10cm are lower than 0.6%. For radial dose function results show that the radial dose function decreased more slowly. Uncertainty calculated is lower 0.4%. The Anisotropy function exhibited little anisotropy about the capsule. Thus Anisotropy function can be considered unity for practical purposes with no significant loss in accuracy due to the thin walls, low cross-sections, and High-Z materials comprising the encapsulation. The uncertainty in calculated data is lower 1 %.
Conclusion:
The calculated dosimetry parameters of Isotron source indicate that Anisotropy function can be considered unity for practical purposes. The radial dose function with increased distances decreased more slowly. Then neutrons can leave their energy at greater distances from the source. Hence, neutrons can be used to treat tumors that are large, due to their greater penetration depth.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
459
459
https://ijmp.mums.ac.ir/article_13151_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13151
Design and manufacturing a CTDI pediatric phantom for CT dosimetry using TLD, ion chambers, and gel dosimetry
Mehrnoosh
Karimipoorfard
Nuclear engineering department, Shiraz University, Shiraz, Iran
author
Zahra
Molaeimanesh
Nuclear engineering department, Shiraz University, Shiraz, Iran
author
Simin
MehdizadehNaderi
Radiation Research Center, Shiraz University, Shiraz, Iran
author
Sedigheh
Sina
Radiation Research Center, Shiraz University, Shiraz, Iran
author
text
article
2018
eng
Introduction:
Nowadays, the demand for CT-scan is increased, and this issue has become a critical subject in radiation protection, because of the risk of cancer especially for children. The quality assurance of CT images is a necessary factor that can effect on children dose. The CT dose index is an important dosimetry index in CT-Scan dosimetry. The purpose of this study is to obtain CTDI in pediatric imaging, using a home-made phantom, and TL dosimetry.
Materials and Methods:
A CTDI pediatric phantom was constructed by Lucite material. The phantom consists of 15 cylindrical slabs with diameter of 10 cm, and thickness of 1cm. One central, and four peripheral holes were drilled on each slab. Several rods were designed to be inserted in the holes. The rods were designed so that the CTDI could be measured by ion chambers, gel dosimetry and TLD. To obtain the CTDI, fifty TLD chips were placed in small holes drilled on the rods. The CTDI100 was estimated using the results of TLDs located in central, and peripheral rods. The measurements were repeated using a 10-cm ion chamber. Finally, the CTDI was calculated as: CTDIW=1/3CTDI100, central+2/3CTDI100, pereperal
Results:
According to the results of this study, CTDIw values for head imaging, obtained by TLD and ion chamber were 46.42, 50.75 mGy respectively.
Conclusion:
The designed phantom can be effectively used in pediatric CT dosimetry. The slab form of the phantom allows us to use radio-chromic dosimeters for CT dosimetry. Further, it can be concluded that the multi-application phantom is useful for use in CT-scan centers.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
460
460
https://ijmp.mums.ac.ir/article_13152_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13152
Designed free-lead composite shields for diagnostic medicine radiation fields by using MCNPX code
Zahra
Molaeimanesh
Medical Radiation Engineering department, Shiraz University, Shiraz, Iran.
author
Mehdi
Zehtabian
Medical Radiation Engineering department, Shiraz University, Shiraz, Iran.
author
Zahra
Dadashi-nasab
Medical Radiation Engineering department, Shiraz University, Shiraz, Iran.
author
text
article
2018
eng
Introduction:
Nowadays, applications of free-lead radiation shields are increased specially for weighting factor and toxicity of lead elements. Although touching the lead may be results in the nervousand blood system of body, it is not exactly proven yet. Protective measures are the fundamental parts of radiation protection. On the other hand, high weighting factor of lead shields are caused to fallow off using apron just in necessary situations. The primary principle of radiation protection is based on ALARA (As Low as Reasonable Achievable) law. Therefore, free-lead shields are attended of investigator. Three factors were proposed for designing radiation shields consist of: percent of attenuating against radiation in field, weight and cost. Choose of radiation shields are usually based on these three factors.
Materials and Methods:
In this study, attenuating factor, weight and cost are proposed for designing composite radiation shields. A source of radiation is collimated like X-ray machines in diagnostic medicine fields. The source has 90, 100 and 120keV spectrums that is output of IPEM78 software. The composite consists of the following eight elements. Tungsten(W), Barium(Br), Bismuth(Bi), Antimony(Sb), Cadmium(Cd), Cerium(Ce), Gadolinium(Gd) and Tin(Sn) are simulated by MCNPX code. The composites include one, two or three element with variant percentage. The dimension of each designed shield (composites and lead) in MCNPX code is 15*15*0.05cm3. Tallies F4 and F6 are applied for estimating local flux behind the shield. All the simulation codes with a standard deviation less than 0.5% are accepted. The relative flux of each composites is calculated by: Frel= Festimated/ Freal.
Results:
For composites which has two elements consist of W-Ce (55.16%-44.84%), W-Sb (52.38%- 47.62%) and W-Cd (31.25%-68.75%) are 63.4%, 50.4% and 47.7%, respectively. The relative flux of the composites with three elements consist of W-Ce-Cd (50%-30%-20%), W-Bi- Ce (45%-28%-27), W-Sn-Ce (46%-50%-4%), W-Sn-Cd (44%-50%-6%) and W-Sn-Bi (44%-50%-
6%) are Frel 58.1%, 55.9%, 51.6%, 49.5% and 49.2%, respectively. weight of These composites are equal to the weight of a common lead shield, while they have a higher attenuating factor.
Conclusion:
The results show that the pure elements have a better attenuating than oxide and sulfite of them in markets. If the cost wasn’t important, pure Gd could be good choice with the best attenuating factor. If an equipped laboratory was available, the composite with W could be the best choice with a reasonable cost. Optimization of these three factors depends on the importance of the factors.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
461
461
https://ijmp.mums.ac.ir/article_13153_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13153
Investigation of dose distribution 252Cf Isotron brachytherapy source based on TG-43U1 protocol by Monte Carlo method.
Ome Leila
Ahmadi
Ph. D Student of Nuclear Physics, Faculty of Physics and Nuclear Engineering, Shahrood University of Technology, Shahrood, Iran
author
Hossein
Tavakoli-Anbaran
Associate Professor, Faculty of Physics and Nuclear Engineering, Shahrood University of Technology, Shahrood, Iran
author
text
article
2018
eng
Introduction:
The commercial 252Cf sources are too large in size and clinical applications of neutron brachytherapy (NBT) are limited to a small number of intracavitary treatments of cervical cancers. Recently, under the Cooperative Research and Development Agreement (CRADA) with Isotron Inc., the Oak Ridge National Laboratory (ORNL) encapsulated a new medical 252Cf sources, called Isotron sources that used to intracavitary and interstitial brachytherapy. On the other hand, prior to the clinical application of brachytherapy sources, their dose distributions should be investigated. In this study, Monte Carlo calculations of dose distribution the 252Cf Isotron source is done in the water phantom.
Materials and Methods:
Dose distributions parameters based on TG-43U1 protocol are radial dose function and anisotropy function. Physical and geometrical parameters of the 252Cf source were simulated by MCNPX (2.6.0) code based on TG-43U1 protocol in the water medium. To estimate the dose rate distribution in water, the source was situated in the center of a spherical 20 cm radius water phantom. The Radial dose function was determined in water, in a cylindrical annulus 0.2 mm × 0.2mm deep positioned along the transverse axis at distances ranging from 0.5 to 10 cm from the source center. The neutron absorbed doses in water were calculated using F6 tallies. Anisotropy functions were calculated at intervals of 1, 2, 3, 4, 5, 10 cm and at different polar angles from θ=0º to 90º with respect to the source long axis in the water phantom.
Results:
Statistical uncertainty for neutron absorbed dose rates at r ≤ 3.5 cm are lower than 0.3%, and at 4-10cm are lower than 0.6%. For radial dose function results show that the radial dose function decreased more slowly. Uncertainty calculated is lower 0.4%. The Anisotropy function exhibited little anisotropy about the capsule. Thus Anisotropy function can be considered unity for practical purposes with no significant loss in accuracy due to the thin walls, low cross-sections, and High-Z materials comprising the encapsulation. The uncertainty in calculated data is lower 1 %.
Conclusion:
The calculated dosimetry parameters of Isotron source indicate that Anisotropy function can be considered unity for practical purposes. The radial dose function with increased distances decreased more slowly. Then neutrons can leave their energy at greater distances from the source. Hence, neutrons can be used to treat tumors that are large, due to their greater penetration depth.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
462
462
https://ijmp.mums.ac.ir/article_13154_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13154
Normal Tissue Complication Probability (NTCP) modeling and validation of quantitative analysis of normal tissue effects in the clinic (QUANTEC) guideline using quality of life questionnaire for parotid gland during head and neck radiotherapy
Hossein
Abbassian
Medical Physics Department, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
author
Alireza
Amouheidari
Department of Radiation Oncology, Milad Hospital, Isfahan, Iran
author
Parvaneh
Shokrani
Medical Physics Department, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
author
text
article
2018
eng
Introduction:
Radiation therapy is the main treatment method for head and neck cancers, which comprise 3–5% of all cancers. A major side effect of this treatment is complication of the parotid glands, i.e. xerostomia, which occurs at relatively low doses. This complication leads to mouth dryness which is the most common problem for head and neck cancer survivors. There are different grades of xerostomia and severe xerostomia is defined as a long-term reduction in the function of salivary gland to less than 25% relative to the pre-radiotherapy baseline value. The grading of xerostomia is usually assessed by patient self-reports carried out by the quality of life questionnaire (QoL), designed based on indigenous criteria and internationally recognized protocols. In recent years several studies have focused on normal tissue complication probability (NTCP) modeling of xerostomia using quality of life questionnaires with or without functional analysis based on various standard model parameters. Lyman (LKB) model is commonly used to predict the normal tissue complication probability (NTCP). This model uses the patient’s calculated dose volume histogram of (DVH) of an organ at risk (OAR) and the dose response curve parameters. The quantitative analysis of normal tissue effects in the clinic (QUANTEC) effort is to refine the guidelines based on 3D dose/volume and outcome data. According to QUANTEC guideline to limit the severity of xerostomia, maximum dose received by one or both of parotid glands should be 20 Gy and 25 Gy (20/25 Gy), respectively. The aim of this study was to evaluate the NTCP model parameters for all grades of acute parotid complications using the LKB model during head and neck conformal radiotherapy treatment and using a QoL questionnaire. Materials and Methods:
50 patients with head and neck cancer who have been referred for radiotherapy to Milad Hospital in Isfahan, Iran, were selected. QoL questionnaire datasets of patients with squamous cell carcinoma and lymph node cancers beside the parotids were within the radiation field were analyzed. The European organization for research and treatment of cancer (EORTC) QLQ HN35 was used in three stages (before, during and at the end of treatment). Prescribed dose per fraction was modified to 2 Gy/fraction equivalent dose for each patients. The LKB model with DVH reduction to form the equivalent uniform dose (EUD), known as LEUD was used. The model parameters of TD50 (Tolerance Dose 50%) and m was assessed by fitting the patient reported complication data to the normal tissue complication probability (NTCP) curve. Results:
One patient (2%) at stage 2 and 5 patients (10%) at stage 3 experienced grade 3 xerostomia. The dose-response curves (LKB model) for occurrence of xerostomia was fitted to the QoL data which were collected at stages 2 and 3. These parameters were TD50 =23.3Gy, m =1 and TD50 =21.6 Gy, m =1 at stage 2 and stage 3, respectively.
Conclusion:
The agreement between the NTCP modeling based on QoL questionnaire data and the QUANTEC guidelines, confirms the cutoff values of 20/25 Gy to spare the parotid gland.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
463
463
https://ijmp.mums.ac.ir/article_13155_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13155
Review of mechanisms and recent advances in cancer photo thermal therapy
Hasan
Norouzi
Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences.
author
Karim
Khoshgard
Department of Medical Physics, School of Medicine, Kermanshah University of Medical Sciences.
author
text
article
2018
eng
Abstract.
Cancer is a major health problem all over the world. Photo thermal therapy (PTT) is a non-invasive method in cancer treatment. In PTT, the laser light usually in near-infra red region is absorbed and converted to heat in the cancerous tissue. The temperature above 40 ° C in PTT can induce some effects including irreversible damage to proteins, changes in enzyme structures, failed dual DNA repair, and lack of glucose. Low thermal threshold, low pH, and hypoxia condition of cancer cells can be exploited for PTT. But the remaining challenges facing researchers in cancer treatment are limited access, treatment resistant property, cancer metastasis and recurrence as well as normal cell damages. The purpose of this paper is to evaluate the PTT mechanisms and review the novel approaches of PTT in cancer treatment. In last decade, the PTT efficacy has been increased due to recent advances in nanotechnology. Use of nanoparticles (NPs) such as carbon-based NPs, metal NPs (e.g. gold, iron, and palladium) intensifies PTT efficacy due to surface plasmon resonance (SPR) property. Using SPR property and therefore improving the treatment efficiency, less intensive laser can be used for PTT. Therefore, concern about damage to normal cells has been considerably addressed. PTT based on NPs also can reduce the limited access in conventional PTT. Owing to enhanced permeability and retention effect of the NPs in tumors, tumors that are deeper than 3-5 cm can be treated efficiently. Using a proper active targeting of NPs for PTT, we can selectively target the cancer cells including the metastatic ones. PTT in accompany with the NPs can generate intense and sub-cellular localized heat in abnormal cells; therefore, the tumors resistance to PTT have been diminished thorough combination of PTT and chemo/radiotherapy. In conclusion, based recent advances especially in nanotechnology, PTT is a simple & non-invasive treatment that can provide a better output, and can reduce the costs, side effects, and other limitations in cancer treatment.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
464
464
https://ijmp.mums.ac.ir/article_13156_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13156
The Effect of Folic Acid-Conjugated Coated Iron Oxide Nanoparticles in The Radiosensitization of Human Cervical Carcinoma Cell Line at Clinical Electron energies (6MeV)
Hamid
Fakhimikabir
Department of Medical Physics and Medical Engineering, School of Medicine, Isfahan University of
Medical Sciences, Isfahan, Iran
author
Mohamad Bagher
Tavakoli
Department of Medical Physics and Medical Engineering, School of Medicine, Isfahan University of
Medical Sciences, Isfahan, Iran (Email:mbtavakoli1957@@gmail.com, Phone: 09102102414)
author
Ali
Zarrabi
Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, Iran
author
Alireza
Amouheidari
Department of Radiation Oncology, Milad Hospital, Isfahan, Iran
author
Soheila
Rahgozar
Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
author
text
article
2018
eng
Background and Purpose: The objective of this study was to investigate the therapeutic effect of Folic Acid-Conjugated polyglycerol coated iron oxide nanoparticles on the radiosensitivity of HeLa cells when irradiated with 6 MeV electron beams.
Materials and Methods: Different concentrations of iron oxide nanoparticles (PG-SPIONs and FA-PG-SPIONs (25, 50, 100, 200 µg ml-1)) were synthesized by the thermal decomposition technique. The effect of PG-SPIONs and FA-PG-SPIONs in combination with radiation (2, 4, 6 Gy) on the viability of cells and cell survival were estimated using the trypan blue dye exclusion test and MTT assay immediately and 48 h after irradiations, respectively.
Results: It was observed that the penetration rate of uptake for cells treated with > 50 µg ml-1 FA-PG-SPIONs was more than that of non-targeted nanoparticles. The data obtained by trypan blue dye exclusion test showed no significant reduction in cell viability for all groups in comparison with control group. The results revealed that increasing the radiation doses in the presence of the concentrations of the nanoparticles increased the value of radiosensitivity. The most radiosensitivity was obtained at the highest concentration of FA-PG-SPIONs (200 µg ml-1) as well as the longest radiation doses.
Conclusion: It was revealed that higher concentrations of the FA-PG-SPIONs in combination with 6 MeV electron beams could enhance radiosensitization of HeLa cells.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
465
465
https://ijmp.mums.ac.ir/article_13157_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13157
Chest-wall irradiation by kilovoltage x-rays: Observed local control rate versus predicted radiobiological tumor control probability
N
Shahsavani
Department of Radiology & Radiobiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
author
MA
Mosleh-Shirazi
Department of Radiology & Radiobiology, School of Paramedical Sciences,
Ionizing and Non-Ionizing Radiation Protection Research Center,
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
Sh
Omidvari
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
A
Abolhasani Foroughi
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
author
B
Zeinali Rafsanjani
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
author
H
Nasrollahi
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
M
Mohammadianpanah
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
A
Mosalaei
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
N
Ahmadloo
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
M
Ansari
Department of Radiotherapy & Oncology, Shiraz University of Medical Sciences, Shiraz, Iran
author
AE
Nahum
Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
author
text
article
2018
eng
Introduction:
The high local control rates observed in patients with breast cancer who had been treated by modified radical mastectomy, chemotherapy and chest-wall irradiation using 120 kV X-rays (50 Gy in 25 fractions) motivated us to investigate their observed tumor control probability (TCP) and test a well-established radiobiological TCP model against our data.
Materials and Methods:
To evaluate and compare the two TCPs (predicted vs. observed), we used the Royal Marsden TCP model and compared its results with our observed TCP, which was derived from the clinical data of 126 patients treated during a period of 10 years. To obtain typical dose distributions, we selected a representative sample of 10 patients’ CT images with different thicknesses and anatomies of the chest wall and computed the dose distributions by the MCNP Monte Carlo code using a validated model of the 120 kV x-ray tube. Then, the dose volume histogram for each patient’s chest wall target volume was computed and entered into the TCP model in the Biosuite software. Various breast cancer model parameters were then adjusted and the corresponding TCPs were recorded. Clonogenic cell density in the chest wall after mastectomy has not been reported and, therefore, we tested a wide range of values (1, 106 or 109 cells in the whole chest wall).
Results:
The observed TCP in patients was 80.7%. However, the dose distributions in the target volumes were inhomogeneous and large volumes of the targets received lower doses. The mean dose received by 50% of the target volume was 72% of the prescription. Assuming just one cell on the total volume of the chest wall, TCP was in the range 85.9%-99.7%, while for 106 or 109 cells, TCP was always zero irrespective of other model parameters.
Conclusion:
The high local control rate observed despite the highly inhomogeneous dose distributions obtained with this radiotherapy technique is similar to the rate for modern methods, which deliver a homogeneous dose to the whole target volume. This questions the hypothesis that the whole chest wall must receive 50 Gy. Our results add support to the suggested suitability of smaller target volumes for such patients. The model predicted TCPs comparable to the observed rate only when extremely low clonogenic cell densitiy values were used, which requires further investigation.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
466
466
https://ijmp.mums.ac.ir/article_13158_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13158
Evaluation of the Bystander effect caused ultrasound waves on the MCF-7 cell line
Masumeh
Rezaei
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Ahmad
Shanei
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Roghayeh
Kamran Samani
Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Seyed Hossein
Hejazi
Department of Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
Mohammad
Kazemi
Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
author
text
article
2018
eng
Introduction:
Non-target radiation effects are damages and effects that occur without the need for direct radiation exposure in cells. Bystander signals cause non-targeted irradiation effect that has been defined as radiation responses in which non-irradiated cells exhibit irradiated effects as a result of signals from adjacent irradiated cells. In this study, the bystander effects of ultrasound radiation on the MCF-7 cell line have been investigated.
Materials and Methods:
Two main groups were defined as target group and bystander group. Target group contained 3 subgroups. The first subgroup is control group which has no intervention. The second subgroup was exposed to ultrasound with the frequency of 1MHZ and intensity of 0.5 . The Third subgroup was exposed to ultrasound with the frequency of 1MHZ and intensity of 1 . The bystander group has 3 subgroups, too. Bystander subgroups received cell culture medium of target subgroups, respectively. The MTT assay has been investigated for bystander subgroups.
Results:
The MTT assay results showed cell viability in bystander cells that received the culture medium from irradiated target cells has not been reduced. In other words, no significant difference was observed between first and second bystander subgroups with control group (P > 0.05).
Conclusion:
Ultrasound waves with intensity of 0.5 and 1 do not induce the bystander effect on MCF-7 cell line.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
467
467
https://ijmp.mums.ac.ir/article_13159_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13159
Evaluation of a fast method of EPID-based dosimetry for IMRT and Comparison with 3D EPID-based dosimetry system using conventional two- and three-dimensional detectors for VMAT
Arass
Rasaei
Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Raheleh
Rooshenas
Department of medical radiation, engineering faculty, central Tehran branch, Islamic azad university, Tehran, Iran
author
text
article
2018
eng
Introduction: Electronic portal imaging devices (EPIDs) could potentially be useful for intensity-modulated radiation therapy (IMRT) and VMAT QA. The data density, high resolution, large active area, and efficiency of the MV EPID make it an attractive option. However, EPIDs were designed as imaging devices, not dosimeters, and as a result they do not inherently measure dose in tissue equivalent media. EPIDose is a tool designed for the use of EPIDs in IMRT and VMAT QA that uses raw MV EPID images to estimate absolute dose planes normal to the beam axis in a homogeneous medi. However, because of the inherent challenges of the EPID-based dosimetry, validating and commissioning such a system must be done very carefully, by exploring the range of use cases and using well-proven “standards” for comparison. Converted EPID images were compared to 2D diode array absolute dose. To provide a 3D dosimetric evaluation of a commercial portal dosimetry system using 2D/3D detectors under ideal conditions using VMAT.
Material & Method: A 2D ion chamber array, radiochromic film and gel dosimeter were utilized to provide a dosimetric evaluation of transit phantom and pre-treatment fluence’ EPID back-projected dose distributions for a standard IMRT & VMAT plan. In house 2D and 3D gamma methods compared pass statistics relative to each dosimeter and TPS dose distributions.
Results: Fluence mode and transit EPID dose distributions back-projected onto phantom geometry produced 2D gamma pass rates in excess of 97% relative to other tested detectors and exported TPS dose planes when a 3%, 3mm global gamma criterion was applied. Use of a gel dosimeter within a glass vial allowed comparison of measured 3D dose distributions versus EPID 3D dose and TPS calculated distributions. 3D gamma comparisons between modalities at 3%, 3mm gave pass rates in excess of 92%. Use of fluence mode was indicative of transit results under ideal conditions with slightly reduced dose definition.
Conclusions: 3D EPID back projected dose distributions were validated against detectors in both 2D and 3D. Cross validation of transit dose delivered to a patient is limited due to reasons of practicality and the tests presented are recommended as a guideline for 3D EPID dosimetry commissioning; allowing direct comparison between detector, TPS, fluence and transit modes. The results indicate achievable gamma scores for a complex VMAT plan in a homogenous phantom geometry and contributes to growing experience of 3D EPID dosimetry.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
468
468
https://ijmp.mums.ac.ir/article_13160_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13160
Assessment of out-of-field dose calculation algorithm by commercial treatment planning systems in IMRT and 3DCRT
Fahimeh
Faghihi Moghadam
Department of Medical Physics, Faculty of Medical Sciences, Shahid Beheshti University of Medical Science, Tehran, Iran
author
Mohsen
Bakhshandeh
Department of Radiology, Faculty of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
author
Mehdi
Ghorbani
Department of Medical Physics, Faculty of Medical Sciences, Shahid Beheshti University of Medical Science, Tehran, Iran
author
Bahram
Mofid
Department of Radiotherapy, shohada-e-Tajrish Hospital, Shahid Beheshti University of Medical Science.Tehran, Iran
author
text
article
2018
eng
Abstract
Introduction: The accuracy an assessment of out- of- field dose due to secondary cancer risk is clinically important. Actually radiotherapy treatment planning systems are not commissioned for the out-of-field dose calculations, so the estimation of dose distributions by TPSs beyond the borders of treatment fields is not well calculated. Now days using modern radiotherapy techniques such as IMRT because of many advantages is most common, while the increase time delivery and also higher number of monitor units (MU), results to increase peripheral dose which can lead to rise potentially risk of secondary cancers after IMRT. Based on documents, increase in collimator scatter and head leakage has been estimated to increase carcinogenic Risk. Because of lack of the study on modern technique(IMRT) and any type of TPSs, the aim of this project is the evaluation of accuracy of out-of-field dose calculations by Isogary and Eclipse TPSs, through the comparison of phantom measurements. Materials and Methods: In this study, For mesurements 2 phantoms were used in 2 steps, at first for evaluated the Eclipse treatment planning system, and at second step ISogary . The dose value was calculated by the Eclips and also ISogary in 3 different depths e.g., 10,15,20 cm and also in 3 different simple quadrate field size, 10×10, 20×20 and 30×30 cm2 at the 1 up to 8 cm from filed edge in 1cm gap interval. Next this values in the same condition were measured by the water phantom and ion chamber dosimeter (Farmer 0.6 cc PTW) and the reading of each point was convert to the Dose in Gy according to the TRS 398 protocol. In the 2th step the dose values were compared by the Delta4+ phantopm in IMRT technique for 10 patients and in the same condition the dose of Rectum and femoral head and bladder was calculated by the Eclipse TPS. Result: Based on the results of the current study, the underestimation in average was demonstrated 38.80 % in Eclipse TPS. And also in the Isogary TPSs the results showed that the overestimation in the 1 to 8 cm distance from field edge was in average 34.65%. Also in the 10 cm depth the average Error was Significant (P-value<0.05). In IMRT the rectum and bladder and also femoral head dose is underestimated by TPS in comparison with the measured values.
Conclusion: In conclusion based on this results the calculation of dose contributions by the TPSs was poor in out-of-field area. In IMRT technique underestimated of the dose calculations by TPS in the OARs was proved. While the magnitude of the underestimation was different and was more in the organs near the field edge. The underestimation of TPS is increase with increase distance from field edge.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
469
469
https://ijmp.mums.ac.ir/article_13164_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13164
Beam characteristic of P.E collimators Add-on multileaf collimator
Seyed Aliasghar
Rohani
Department of Medical Physics, Tehran University of Medical Science, Tehran, Iran
author
Ghazale
Graily
Department of Medical Physics, Tehran University of Medical Science, Tehran, Iran
author
Seied Rabi
Mahdavi
Radiation biology research center & medical Physics department, faculty of medicine, Iran university of medical
Science, Tehran, Iran
author
Ahmad
Mostaar
Department of Medical Physics, School of Medicine, Shahid Beheshti University of Medical Science, Tehran, Iran
author
text
article
2018
eng
Introduction:
Multileaf collimators (MLCs) are computer-controlled devices which are Useful and cost-effective tools for conformal therapy and intensity modulation radiotherapy (IMRT).
Nowadays MLCs are important and standard configuration of the new medical linear accelerators which are substitute of conventional Blocks and has eliminated the difficulties of working with blocks. MLCs are available from many manufacturers and their designs differ in the way they couple with conventional jaws, number and width of leaves and in their physical and dosimetric characteristics, well understanding on the mechanics and dosimetric characteristics of MLC is the basic task of medical physicist.
Materials and Methods:
In this study some mechanical and dosimetric characteristics of a P.E. Collimators Add-On MLC which is installed on VARIAN CLINAC 2100 C/D are presented. Scatter factors (Sc, Sp, Scp), central axis depth dose and beam profiles were measured before and after installation of MLC. mechanical and Leaf Leakages for 6MV and 18MV beams were measured with Gafchromic EBT3 films.
Results:
radiation and light fields were match below the 2mm acceptable level based on AAPM reports. Average leaf leakage was noted 1.79% for 6MV and 1.98% for 18MV beams, respectively. No significant differences were found in beam profiles, collimator (Sc), phantom (Sp) and total (Sc, p) scatter factors after MLC installation. The percent depth dose data for all fields and both beam energies were within 1.6 % of the original data.
Conclusion:
Based on the Mechanical and dosimetric results which have been achieved from our different standard tests, we found no significant differences between before and after MLC installation Values on Clinac 2100 C/D Varian LINAC.
Iranian Journal of Medical Physics
Mashhad University of Medical Sciences
2345-3672
15
v.
Special Issue-12th. Iranian Congress of Medical Physics
no.
2018
470
470
https://ijmp.mums.ac.ir/article_13166_d41d8cd98f00b204e9800998ecf8427e.pdf
dx.doi.org/10.22038/ijmp.2018.13166