Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
Absorbed Dose Assessment from Short-Lived Radionuclides of Radon (222Rn) Decay Chain in Lung Tissue: A Monte Carlo Study
66
74
EN
Zohreh
Danaei
0000-0002-5079-3737
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
zohrehdanaee69@yahoo.com
Hamid Reza
Baghani
0000-0003-0392-9192
Physics Department, Hakim Sabzevari University, Sabzevar, Iran
hamidreza.baghani@gmail.com
Ali Asghar
Mowlavi
0000-0001-7217-6871
Physics Department,Hakim Sabzevari University, Sbazevar, Iran
aa_mowlavi@yahoo.com
10.22038/ijmp.2019.38027.1486
<strong><em>Introduction:</em></strong> Internal exposure to radon gas progeny can lead to serious biologic damages to the lung tissue. The aim of this study was to evaluate the absorbed dose by lung tissue due to the exposure from short-lived radioactive products of radon (<sup>222</sup>Rn) decay using Monte Carlo simulation.<br /> <strong><em>Material and Methods:</em></strong> A lung equivalent phantom including 64 air sacs was simulated by MCNPX code. Then, the absorbed dose from short-lived radioactive products of radon decay chain including <sup>218</sup>Po, <sup>214</sup>Po, <sup>214</sup>Pb and <sup>214</sup>Bi was calculated for both suspended and deposited states of daughter nuclides inside the lung.<br /> <strong><em>Results:</em></strong> The results showed that alpha decay has more contribution to the lung absorbed dose in comparison with the beta and gamma decay. Furthermore, the received dose by the lung was higher when the radon progenies were deposited inside the lung so that the maximum received dose to lung was 100 times higher than that of calculated in suspended state.<br /> <strong><em>Conclusion: </em></strong>Short-lived daughter radionuclides of radon decay chain, especially alpha emitter products, can be considered as dangerous internal radiation sources. The biological effects of these daughter radionuclides is more severe when are suspended inside the respiratory system.
Radon,Radon Progeny,Lung,Dosimetry,Monte Carlo Method
https://ijmp.mums.ac.ir/article_12971.html
https://ijmp.mums.ac.ir/article_12971_70012f816da4f4b9e0c689ab9f0e5404.pdf
Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
Comparison of Three-Dimensional Double-Echo Steady-State Sequence with Routine Two-Dimensional Sequence in the Depiction of Knee Cartilage
75
80
EN
sepehr
Lotfi Marangaloo
0000-0002-6308-8287
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
seplotfi@gmail.com
Amir shahriar
Ariamanesh
0000-0003-2522-2403
Department of Orthopedic ,Faculty of medicine,Mashhad University of Medical Sciences, Mashhad, Iran
drariamanesh@yahoo.com
Behzad
Aminzadeh
0000-0001-6569-4670
Department of radiology, faculty of medicine, Mashhad University of Medical Sciences, Mashhad, Iran
aminzadehb@mums.ac.ir
Hormoz
abedi
0000-0001-7158-5673
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
habedimp@gmail.com
ali
abbaszadeh
0000-0002-3413-5822
Department of Epidemiology & Biostatistics
School of Health, Mashhad University of Medical Sciences , Mashhad, Iran
aliabbas37254@gmail.com
Alireza
Montazerabadi
0000-0001-8768-0640
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
alireza.montazerabadi@gmail.com
10.22038/ijmp.2019.40783.1578
<strong><em>Introduction:</em></strong> There are some routine two-dimensional sequences, including short tau inversion recovery (STIR), T2-weighted fast-spin echo (T2W-FSE), and proton-density fast spin-echo for diagnosing osteoarthritis and lesions of the knee cartilage. However, these sequences have some disadvantages, such as long scan time, inadequate spatial resolution, and suboptimal tissue contrast which results in loss of image details, as well as missing the visualization of knee cartilage lesions. Three-dimensional (3D) sequences, such as the double-echo steady-state (DESS) sequence can decrease and overcome these problems to the smallest possible amount.<br /> <strong><em>Material and Methods:</em></strong> A total of 15 volunteers with knee pain were examined by a 1.5 Tesla magnetic resonance imaging.The contrast-to-noise ratio (CNR) and thickness values of the knee articular cartilage were measured. The CNR and thickness values were comparedby the Friedman test and the Wilcoxon signed-rank test.<br /> <strong><em>Results:</em></strong> The obtained results showed significant differences between sequences in CNR and thickness values. The DESS sequence with a flip angle of 40°showed the best CNR values and 3D fast low-angle shot (FLASH) showed the worst results. In addition, the results showed no significant differences between FLASH, 3D DESS 40° and 90° in terms of cartilage thickness. However, thickness values of these sequences were much higher than that of the PD, T2, and STIR sequences.<br /> <strong><em>Conclusion: </em></strong>The 3D DESS sequence with two flip angles of 40°and 90° are the best sequences for visualizing the cartilage and the synovial fluid. Because they provide the best contrast between the cartilage and the synovial fluid, it is recommended to use DESS sequences in the evaluation of cartilage defections.
Osteoarthritis,cartilage,MRI,DESS sequence
https://ijmp.mums.ac.ir/article_13673.html
https://ijmp.mums.ac.ir/article_13673_12ec4d1a24b3c17638272bdfa991f226.pdf
Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
A Comparative Study of the Construction of Positron Emission Tomography/Computed Tomography Facilities in Three South African Hospitals
81
89
EN
Nompumelelo
Milldred
Masango
0000-0001-5179-9084
Department of Medical Physics, Faculty of Health Science, Sefako Makgatho Health Science University, Pretoria, South Africa
nompumelelodumako@gmail.com
Bronwin
Prince
Van Wyk
0000-0002-6627-603
Department of Medical Physics, Faculty of Medicine, Dr George MUkhari Hospital, Pretoria, South Africa.
bronwin.vanwyk@smu.ac.za
Modisenyane
Simon
Mongane
University of free State
Faculty: Health Sciences
PO Box Bloemfontein 9300, Republic of South Africa
monganems@ufs.ac.za
10.22038/ijmp.2019.35911.1455
<strong><em>Introduction:</em></strong> Development of higher energy modalities such as positron emission tomography/computed tomography (PET/CT), has led to more complex shielding problems. This is due to several factors, such as the radiopharmaceutical relatively high-administered activity, high patient throughput, and high energies of 511 kilo-electron volt (keV) positron annihilation photons. Therefore, this study aimed to compare three different methods used to determine the required shielding thicknesses of PET/CT facilities.<br /> <strong><em>Material and Methods:</em></strong> The required shielding thicknesses for three facilities were determined by using three different shielding methods, i.e. narrow beam, broad beam and Monte Carlo approximation. The design goal was chosen as 6 mSv/year for radiation workers and 1 mSv/year for the public. In addition, occupancy factors (T) were established, and all calculations had a use factor (U) of 1. The workload (W) of facilities and thicknesses of all barriers were then calculated for the three facilities.<br /> <strong><em>Results:</em></strong> For narrow beam approximation the average required thicknesses obtained were 6.16 mm lead, 5.12 cm concrete and 2.95 cm iron. Broad beam approximation required an average of 7.55 mm lead, 8.01 cm concrete and 2.96 cm iron thicknesses. Monte Carlo approximation required 7.62 mm lead, 10.59 cm concrete and 2.94 cm iron thicknesses.<br /> <strong><em>Conclusion: </em></strong>The narrow beam approximation demonstrated the least shielding thickness required for the materials used in this study, which can lead to under-shielding. The broad beam and Monte Carlo approximations demonstrated higher required shielding thickness although there were discrepancies between these two approximations for lead, concrete, and iron.
PET/CT,Shielding,Monte Carlo
https://ijmp.mums.ac.ir/article_13422.html
https://ijmp.mums.ac.ir/article_13422_56532caa0b374b4cb68425b3adea1b6c.pdf
Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
A Comparative Study of 3-D Conformal Radiotherapy Treatment Plans with and Without Deep Inspiration Breath-Hold Technique for Left-Sided Breast Cancer
90
98
EN
Mohammed
Ali
Morsy
0000-0002-5047-3944
Physics Department, Faculty of Sciences, Suez Canal University
ph_moh_ali@yahoo.com
Ehab
Marouf
Attalla
10.22038/ijmp.2017.2
Prof. of Medical physics ; National Cancer Institute, cairo university &amp; children&#039;n Cancer Hospital ,Egypt
attalla.ehab@gmail.com
Wahib
Mohamed
Attia
0000-0001-8628-9252
Professor of Physics,
Physics Department,
Faculty of Science (Ismailia)
Suez Canal University
wahibattia@hotmail.com
10.22038/ijmp.2019.40081.1545
<strong><em>Introduction:</em></strong> The rate of cardiac diseases have increased among patients who underwent radiotherapy for left-sided breast cancer. The study’s aim was evaluate the dose to organs at risk in free-breathing 3-dimensional conformal (FB-3DCRT) against 3-dimensional conformal deep inspiration breath-hold (3DCRT-DIBH) in patients with left-sided breast cancer.<br /> <strong><em>Material and Methods:</em></strong> In total, 15<sup>th</sup> female patients diagnosed with left-sided breast cancer were included in this study from December 2017 to December 2018. All selected patients were subjected to FB and DIBH computed tomography (CT) scans. The 3DCRT plans were created on both DIBH and FB scans for each selected patient. Various doses were obtained from dose-volume histograms and then compared. The data were analyzed in SPSS software (version 20) (IBM; IL). P-value less than 0.05 was considered statistically significant.<br /> <strong><em>Results:</em></strong> The results obtained from the DIBH and FB conditions were compared. The average maximum dose and V95% for planning target volume <em> </em>was approximate for both DIBH and FB, and the average mean doses to the heart, left anterior descending artery, and left lung were decreased by 40.50% (P=0.0003), 54.30% (P=0.02),and 18.50% (P=0.0002) in DIBH, respectively. Moreover, the heart V25% and V30% were decreased by 36% (P=0.06) and 35.8 % (P=0.03) in DIBH, respectively. Regarding the left lung, a decrease by 18.10% in V10% (P=0.0006) and 18% in V20% (P=0.0002) was also observed in DIBH.<br /> <strong><em>Conclusion: </em></strong>The 3DCRT-DIBH for patients with left-sided breast cancer maintained the benefits of radiotherapy while minimizing cardiac risks. All patients completed their treatment smoothly.
left,Sided Breast Cancer FB and DIBH 3,DCRT Plans
https://ijmp.mums.ac.ir/article_13421.html
https://ijmp.mums.ac.ir/article_13421_124845c75c1e08236bd324393ee9cdbe.pdf
Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
Establishment of Diagnostic Reference Levels and Estimation of Effective Dose from Computed Tomography Head Scans at a Tertiary Hospital in South Africa
99
106
EN
Mpumelelo
Nyathi
0000-0001-5874-7957
Department of Medical Physics
Sefako Makgatho Health Sciences University
SouthAfrica
mpumelelo.nyathi@smu.ac.za
10.22038/ijmp.2019.39685.1531
<strong><em>Introduction:</em></strong> Head scans are the most frequently performed computed tomography (CT) examinations worldwide. However, there is growing concern over the probability of increased cancer risks among the exposed populations. Diagnostic reference levels (DRLs) identify radiation dose that is not commensurate with clinical objectives. The aim of this study was to establish DRLs for CT head procedures and estimate effective dose (ED).<br /> <strong><em>Material and Methods:</em></strong> The dose absorbed by the head slice of a Rando Alderson phantom was measured using calibrated lithium fluoride thermoluminescent dosimeters (TLDs) exposed to a CT scanner operated on clinical parameters. The measurements were done at the periphery and center of the slice, and repeated twice with a new set of TLDs. The radiation dose absorbed by the TLDs was read using a Harshaw TLD reader, Model 5500. The measured doses were used to calculate the weighted CT dose index (CTDI<sub>w</sub>), CT dose index volume (CTDI<sub>v</sub>), and dose length product (DLP). Finally, the ED was calculated using the formula; ED = k × DLP, where <em>k</em> was considered as 0.0021.<br /> <strong><em>Results:</em></strong> The mean absorbed dose was 30.9 mGy, while the established CTDI<sub>v</sub> and DLP values for the head protocol were 40 mGy and 990 mGy.cm, respectively. Additionally, the ED was calculated as 2.1 mSv. These values compared well with some international values.<br /> <strong><em>Conclusion: </em></strong>According to the results of the present study, the established CTDI<sub>v</sub>, DLP, and ED for head scan were well-compared with some international values, except in the cases using different scan lengths and scanner algorithms.
Effective Dose,Computed Tomography Dose,Absorbed Dose
https://ijmp.mums.ac.ir/article_13341.html
https://ijmp.mums.ac.ir/article_13341_d60ca8a5bc9f6cc873eff2d8665762e6.pdf
Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
Radiological Hazard Assessment of Radionuclides in Sediment and Water Samples of International Meighan Wetland in Arak, Iran
107
113
EN
Reza
Pourimani
0000-0002-0102-0578
Department of Nuclear Physics,
Faculty of Science
Arak University,
Arak 38156
Iran
r-pourimani@araku.ac.ir
Ramin
Fardad
0000-0001-7775-9857
Department of Physics, Faculty of Science, Arak University, Arak, Iran
fardad_ramin@yahoo.com
Hasan
Khalili
0000-0002-2839-4158
Department of Physics, Faculty of Science, Arak University, Arak , Iran
h-khalili@araku.ac.ir
10.22038/ijmp.2019.39081.1512
<strong><em>Introduction:</em></strong> There are natural and artificial radioactive nuclei in our environment, as well as in the structure of the living organism. Currently, industrial and municipal pollution has also an impact on increasing the level of radiation. The present study investigated the effect of inlet water from Arak Wastewater Treatment Plant on international Meighan Wetland and assessed the radiological indicators of sediments and water samples in this area.<br /> <strong><em>Material and Methods:</em></strong> In this study, the specific activity of radionuclides in water and sediment samples taken from the water entry areas of the international Meighan wetland was determined using a high purity germanium detector (Baltic Scientific Instrument LTD, 005- Latvia). Radiological indices for collected samples were calculated, and the topographical maps of radiation dose distribution were plotted using Surfer software (version 13).<br /> <strong><em>Results:</em></strong> Specific activities of <sup>226</sup>Ra, <sup>232</sup>Th, <sup>40</sup>K, and <sup>137</sup>Cs in sediment samples were in the range of 14.44-26.58, 22.78-34.56, 360.84-447.79, and 0.7-13.03 , respectively. The average values of the external hazard index for sediment samples were calculated at 0.25.<br /> <strong><em>Conclusion: </em></strong>According to the obtained results, it can be concluded that pollution is more embedded in the Treatment Plant's basin, and a small amount goes to the wetlands. Radioactivity in the research area is normal, and topographic maps show that the distance from the entrance reduces the activity of radium and increases the activity of cesium. Assessment of hazard indicators showed that radiation levels in this area are not dangerous to human health.
Cancer,Dosage,Natural radiation,sediment,water
https://ijmp.mums.ac.ir/article_13262.html
https://ijmp.mums.ac.ir/article_13262_d1140d86c214ac02ed0dd2239bef5d70.pdf
Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
Assessment of Different Training Methods in an Artificial Neural Network to Calculate 2D Dose Distribution in Radiotherapy
114
119
EN
Mahdi
Saeedi-Moghadam
0000-0002-6235-3632
Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
m_saeedimoghadam@yahoo.com
Kamal
Hadad
0000-0003-4495-0350
Nuclear Engineering Department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran.
hadadk@shirazu.ac.ir
Banafsheh
Zeinali-Rafsanjani
0000-0002-4815-0345
Medical imaging research center, Shiraz University of medical sciences, Shiraz, Iran
b.zeinali.r@gmail.com
Reza
Jalli
0000-0001-9167-4737
Medical imaging research center, Shiraz university of medical sciences, Shiraz, Iran
jallireza@yahoo.com
10.22038/ijmp.2019.39429.1522
<strong><em>Introduction:</em></strong> Treatment planning is the most important part of treatment. One of the important entries into treatment planning systems is the beam dose distribution data which maybe typically measured or calculated in a long time. This study aimed at shortening the time of dose calculations using artificial neural network (ANN) and finding the best method of training the ANN using Monte Carlo-N-particle (MCNP5) modeling.<br /> <strong><em>Material and Methods:</em></strong> Back-propagation learning algorithm was applied to design the neural network. The ANN was trained by MCNP5 calculations, and different kinds of methods were tested to determine the best method for training. In order to evaluate the accuracy of the ANN, the beam profiles and percentage depth dose (PDD) in the field size of 15×15 cm<sup>2</sup> were anticipated by ANN using various training methods. Eventually, the results were compared with those obtained from the MCNP5 code.<br /> <strong><em>Results:</em></strong> There were good agreements between the results of comparing MCNP5 calculations with experimental measurements. Among the different training methods, Trainbfg had the least error for calculation of PDD and beam profile.<br /> <strong><em>Conclusion: </em></strong>The best training method was found to be Trainbfg, and the results revealed the sufficient accuracy of the modeled ANN.
Simulation Training,Radiation Dosage,Radiotherapy Planning Computer-Assisted
https://ijmp.mums.ac.ir/article_13834.html
https://ijmp.mums.ac.ir/article_13834_fa2b431ecfcd12590317ef6c75741b3a.pdf
Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
Dosimetric Study of an Indigenous and Heterogeneous Pelvic Phantom for Radiotherapy Quality Assurance
120
125
EN
Sudha
Singh
0000-0002-6542
University Department of Physics,
Ranchi University, Ranchi- 834008, Jharkhand State, India.
ssingh8@gmail.com
payal
raina
payalraina2008@gmail
Ranchi university, Ranchi
payalraina2008@gmail.com
Om Prakash
Gurjar
0000-0001-9262-0132
All India Institute of Medical Sciences (AIIMS), Bhopal
ominbarc@gmail.com
10.22038/ijmp.2019.39332.1520
<strong><em>Introduction: </em></strong>In vitro dosimetric verification prior to patient treatment plays a key role in accurate and precision radiotherapy treatment delivery. Since the human body is a heterogeneous medium, the aim of this study was to design a heterogeneous pelvic phantom for radiotherapy quality assurance.<br /> <strong><em>Material and Methods:</em></strong> A pelvic phantom was designed using wax, pelvic bone, borax powder, and water mimicking different biological tissues. Hounsfield units and relative electron densities were measured. Various intensity-modulated radiotherapy (IMRT) plans were imported to the pelvic phantom for verification and implemented on the Delta 4 phantom. The quantitative evaluation was performed in terms of dose deviation, distance to agreement, and gamma index passing rate.<br /> <strong><em>Results:</em></strong> According to the results of the CT images of an actual patient, relative electron densities for bone, fat, air cavity, bladder, and rectum were 1.335, 0.955, 0.158, 1.039, and 1.054, respectively. Moreover, the CT images of a heterogeneous pelvic phantom showed the relative electron densities for bone, fat (wax), air cavity, bladder (water), and rectum (borax powder) as 1.632, 0.896, 0.159, 1.037, and 1.051, respectively.The mean percentage variation between planned and measured doses was found to be 2.13% within the tolerance limit (< ±3%) .In all test cases, the gamma index passing rate was greater than 90%.<br /> <strong><em>Conclusion: </em></strong>The findings showed the suitability of the materials used in the design of the heterogeneous phantom. Therefore, it can be concluded that the designed phantom can be used for regular radiotherapy quality assurance
Algorithm,Phantom,CT Number,Intensity Modulated Radiotherapy
https://ijmp.mums.ac.ir/article_13616.html
https://ijmp.mums.ac.ir/article_13616_53c4400796e9f168aab951235749980c.pdf
Mashhad University of Medical Sciences
Iranian Journal of Medical Physics
2345-3672
17
2
2020
03
01
Investigation of Neutron Contamination of Flattening Filter and Flattening Filter-Free 10-MV Photon Beams in Elekta InfinityTM Accelerator
126
132
EN
Sitti
Yani
0000-0002-8947-7395
Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung
sitti.yani@s.itb.ac.id
Indra
Budiansah
0000-0003-2835-8517
Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung
indra.budiansah@gmail.com
Fauzia Puspa
Lestari
0000-0001-5567-4959
Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung
fplestari@gmail.com
Mohamad
Rhani
0000-0002-6960-1248
Department of Radiation Oncology, Concord International Hospital, Singapore/ Singapore
mohamad.fahdillah@gmail.com
Rasito
Tursinah
0000-0003-1743-2443
National Nuclear Energy Agency
rasito@batan.go.id
Freddy
Haryanto
0000-0002-6353-8460
Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung
freddy@fi.itb.ac.id
10.22038/ijmp.2019.37195.1471
<strong><em>Introduction:</em></strong> This study aimed to measure the neutron contamination of flattening filter (FF) and flattening filter-free (FFF) 10-MV photon beams delivered by the Elekta Infinity<sup>TM</sup> accelerator.<br /> <strong><em>Material and Methods:</em></strong> The photoneutron spectrum produced by the Linac head was evaluated using a Monte Carlo (MC) simulation. The geometry and composition of the head Linac material were modelled based on information obtained from the manufacturer. In this simulation, MC N-Particle Transport Code software (MCNP6) was utilized to model the Linac head and simulate the particle transport. Evaluation of neutron contamination was carried out for the Linac with FF and without it (i.e., FFF). In this regard, the FFF beam was built by removing the FF from the Linac components. The scoring plane, as the neutron spectra calculation area for FF and FFF beams, was placed 99 cm from the target.<br /> <strong><em>Results:</em></strong> The neutron type produced by the head Linac Elekta Infinity<sup>TM</sup> 10-MV photon mode was mostly thermal and fast. Although there were differences in the neutron intensity of FF and FFF beams, the type of neutrons produced by these two modes had the same energy. Based on the photoneutron reaction energy threshold, it can be concluded that the neutrons produced from the head Linac were the result of photoneutron interactions of high-energy photons with molybdenum-96 and tungsten-184 isotopes.<br /> <strong><em>Conclusion: </em></strong>The photoneutron quantity did not change for FF and FFF beams; however, a larger quantity of neutrons was produced in the FF beam.
Neutron,Monte Carlo Method Photon Beam,Linear Accelerator
https://ijmp.mums.ac.ir/article_13423.html
https://ijmp.mums.ac.ir/article_13423_85d1bb69744dae139e37e4ea4cf691d8.pdf