@article { author = {Nabavi, Mansoureh and Nedaie, Hassan Ali and Salehi, Narges and Naderi, Mansour}, title = {Stereotactic Radiosurgery/Radiotherapy: A Historical Review}, journal = {Iranian Journal of Medical Physics}, volume = {11}, number = {1}, pages = {156-167}, year = {2014}, publisher = {Mashhad University of Medical Sciences}, issn = {2345-3672}, eissn = {2345-3672}, doi = {10.22038/ijmp.2014.2621}, abstract = {"Stereotactic" is an exact radiotherapy treatment modality which implements invasive and non-invasive facilities for improving precise dose delivery. Stereotactic refers to three-dimensional localization of a specific point in space by a unique set of coordinates that relate to a fixed external reference frame. An accurate delivery of radiation is attainable using these techniques with high precision (1-2 mm) which leads to dose reduction in critical organs and adjacent normal tissues while delivering the highest dose to tumoral tissue. Stereotactic irradiation consists of two techniques of delivery: Stereotactic RadioSurgery (SRS) which is an accurate single fractionated delivery of radiation to intracranial lesions and is attained by converging series of radiation beams on a target from various angles. Stereotactic Radiotherapy  (SRT) which is a fractionated irradiation of intra and extra cranial lesions. This review article intends to highlight the radiobiological and physical aspects of these techniques and also introduces three commercially available stereotactic machines systematically and functionally.}, keywords = {Equipments,Stereotactic radiosurgery,stereotactic radiotherapy}, url = {https://ijmp.mums.ac.ir/article_2621.html}, eprint = {https://ijmp.mums.ac.ir/article_2621_8411707e06edf38cdf6ff5830d504f48.pdf} } @article { author = {Basirjafari, Sedigheh and Aghayari, Saeideh and Poorabas, Seyed Mohammad and Moladoust, Hassan and Asadinezhad, Mohsen}, title = {Assessment of Outdoor Gamma Radiation Dose Rates in 49 Cities of Guilan Province, IRAN}, journal = {Iranian Journal of Medical Physics}, volume = {11}, number = {1}, pages = {168-174}, year = {2014}, publisher = {Mashhad University of Medical Sciences}, issn = {2345-3672}, eissn = {2345-3672}, doi = {10.22038/ijmp.2014.2622}, abstract = {Introduction Guilan is one of the provinces in North of Iran, with population of 2,480,874 and a total area of ​​14,042 square kilometers. This study assesses the outdoor natural gamma dose rates in the air of 49 cities in Guilan and calculates corresponding average annual effective dose. Materials and Methods A total of 260 different sample points measurements were carried out. The results include both terrestrial and cosmic ray components of gamma radiation level. Results The outdoor gamma dose rates range from 65 to 127 nSv h-1 with the mean of 94 ± 24 nSv h-1. Conclusion The average outdoor gamma dose rate for Guilan determined in this study is significantly higher in comparison with values reported by UNSCEAR 2000 from different countries with the mean of 59 nSv although in comparison with many provinces of Iran, it is lower.}, keywords = {Background Radiation,Guilan,Iran,Outdoor Dose Rate}, url = {https://ijmp.mums.ac.ir/article_2622.html}, eprint = {https://ijmp.mums.ac.ir/article_2622_5b22e391e35a6b7a9b8be1b3eb03af5f.pdf} } @article { author = {Eidi, Ramezan and Aghamiri, Seyed Mahmoudreza and Sheibani, Shahab and Jaberi, Ramin and Pourbeigi, Hossein and Mashayekhi Galatoiyeh, Mohsen and Hosseini Daghigh, Seyed Mohsen}, title = {Silastic Thickness Optimization in Uveal Melanoma Brachytherapy by Monte Carlo Method}, journal = {Iranian Journal of Medical Physics}, volume = {11}, number = {1}, pages = {175-181}, year = {2014}, publisher = {Mashhad University of Medical Sciences}, issn = {2345-3672}, eissn = {2345-3672}, doi = {10.22038/ijmp.2014.2624}, abstract = {Introduction In order to treat uveal Melanoma , first, radioactive seeds are laid on a silicone- made substance which is called Silastic after that they are inserted in the plaque, and finally, this plaque containing silicone-made substance is stitched to the sclera surface. The dose gradient within the tumor and healthy tissues can be varied due to changing the Silastic thickness between sclera surface and radioactive seeds. In turn, this leads to difference in the amount of absorbed dose of tumor and healthy tissues. Present study is to investigate the optimum Silastic thickness in uveal Melanoma brachytherapy.  Materials and Methods To measure changes of depth dose of the plaque in a sphere with a radius of 12 mm, MCNP4C code was applied. Exact specifications of a 20-mm Collaborative Ocular Melanoma Study (COMS) plaque, Silastic and three I-125 seed sources, 6711 model were integrated in simulation. Dose calculations were performed using F6 tally in spheres with a radius of 0.2 mm. Results By measuring the changes of dose rate of plaque in distances of 0.2 to 18 mm from the sclera surface and having the prescribed dose for the absolute treatment of eye melanoma, final absorbed doses by tumor and healthy tissues for each different Silastic thicknesses of 0, 0.5, 1, 1.5, and 2 were calculated. Conclusion Considering the results and sclera tolerance, it was concluded that the thickness of Silastic must not exceed 0.5 mm, because increasing the Silastic thickness from this area, increases absorbed dose by healthy tissues and also the treatment time.}, keywords = {Uveal Melanoma,I-125 Source,Monte Carlo,Silastic}, url = {https://ijmp.mums.ac.ir/article_2624.html}, eprint = {https://ijmp.mums.ac.ir/article_2624_353267d0fde7df5cda8a87e020792667.pdf} } @article { author = {Gholamhosseinian-Najjar, Hamid and Bahreyni-Toosi, Mohammad-Taghi and Zare, Mohammad-Hossein and Sadeghi, Hamid-Reza and Sadoughi, Hamid-Reza}, title = {Quality Control Status of Radiology Centers of Hospitals Associated with Mashhad University of Medical Sciences}, journal = {Iranian Journal of Medical Physics}, volume = {11}, number = {1}, pages = {182-187}, year = {2014}, publisher = {Mashhad University of Medical Sciences}, issn = {2345-3672}, eissn = {2345-3672}, doi = {10.22038/ijmp.2014.2625}, abstract = {Introduction Using ionization radiation for diagnostic and treatment fields has increased worldwide dramatically. This issue causes an increase in the absorbed and collective doses in society noticeably. With regard to two main principles in radiation protection, i.e., justification and optimization, it is necessary to have imaging process with minimum dose to patients and personnel. For achieving this, it is vital to perform quality control tests regularly. On this topic, many studies have been performed and reported worldwide  which  show necessities and meaningfulness of QC tests. Materials and Methods In this study, Unfors Mult-O-Meter model 303 is used for surveying accuracy of kVp and time, linearity of exposure with mAs, and reproducibility of exposure. Results According to recommendations of AAPM (2002) and ICRP 103, in this study, 27% of apparatuses in accuracy of kVp, 45% in accuracy of timer, and 30% in accuracy of reproducibility were out of accepted range. Conclusion In surveyed apparatuses, both ends of operating range have large errors in therefore it is recommended that these devices should not be used  in the mentioned regions. Performing strict quality control on all radioactive devices is one of the radiation protection priorities that should be done periodically .With regard to the results, repair, substitution or omition of  some devices are suggested.  }, keywords = {Mult-O-Meter, Quality Control,Radiography,Reproducibility of Results}, url = {https://ijmp.mums.ac.ir/article_2625.html}, eprint = {https://ijmp.mums.ac.ir/article_2625_4c0b20e00d0dbe21d64863b06388e480.pdf} } @article { author = {Mesbahi, Asghar and Zakariaee, Seyed-Salman}, title = {Optical Characterization of NIPAM and PAGAT Polymer Gels for Radiation Dosimetry}, journal = {Iranian Journal of Medical Physics}, volume = {11}, number = {1}, pages = {188-194}, year = {2014}, publisher = {Mashhad University of Medical Sciences}, issn = {2345-3672}, eissn = {2345-3672}, doi = {10.22038/ijmp.2014.2626}, abstract = {Introduction The purpose of the current study was to determine optical sensitivity of N-isopropyl acrylamide NIPAM and polyacrylamide gelatin and tetrakis hydroxymethyl phosphoniun chloride (PAGAT) polymer gels for different wavelength of visible light spectrum applied in optical computed tomography method. Materials and Methods NIPAM and PAGAT polymer gels with conventional formulations used for polymer gel dosimetry in radiation therapy were prepared. Using a laboratory spectrophotometer, light absorbance against wavelength of light spectrum from 400 to 700 nm was measured. The optical absorbance-dose response curves were obtained for different wavelengths and the results were compared to find the wavelength where the highest sensitivity of polymer gels is occurred. Results The results showed light wavelength dependency for polymer gels optical absorbance-dose sensitivity. The highest sensitivity was seen in the blue part of visible light at wavelengths of 440 and 460 nm for PAGAT and NIPAM, respectively.  Moreover, the sensitivity of NIPAM gel was higher than PAGAT for all studied wavelengths. Conclusion The sensitivity of both gels varied considerably with light wavelength and was higher in shorter wavelength of visible light. It is recommended to study optical absorbance-dose sensitivity of polymer gels for selecting the optimum light wavelength for optical measurements and optical computed tomography applications.}, keywords = {Gel Dosimetry,NIPAM polymer,Optical Response,PAGAT polymer}, url = {https://ijmp.mums.ac.ir/article_2626.html}, eprint = {https://ijmp.mums.ac.ir/article_2626_b8b82d9064ef27d2165312a32d0430e2.pdf} } @article { author = {Tahmasebi-Birgani, Mohamad Javad and Bayatiani, Mohamad Reza and Seif, Fatemeh and Zabihzadeh, Mansur and Shahbazian, Hojatolah}, title = {Electron Beam Dose Distribution in the Presence of Non-Uniform Magnetic Field}, journal = {Iranian Journal of Medical Physics}, volume = {11}, number = {1}, pages = {195-204}, year = {2014}, publisher = {Mashhad University of Medical Sciences}, issn = {2345-3672}, eissn = {2345-3672}, doi = {10.22038/ijmp.2014.2630}, abstract = {Introduction Magnetic fields are capable of altering the trajectory of electron beams andcan be used in radiation therapy.Theaim of this study was to produce regions with dose enhancement and reduction in the medium. Materials and Methods The NdFeB permanent magnets were arranged on the electron applicator in several configurations. Then, after the passage of the electron beams (9 and 15 MeV Varian 2100C/D) through the non-uniform magnetic field, the Percentage Depth Dose(PDDs) on central axis and dose profiles in three depths for each energy were measured in a 3D water phantom. Results For all magnet arrangements and for two different energies, the surface dose increment and shift in depth of maximum dose (dmax) were observed. In addition, the pattern of dose distribution in buildup region was changed. Measurement of dose profile showed dose localization and spreading in some other regions. Conclusion The results of this study confirms that using magnetic field can alter the dose deposition patterns and as a result can produce dose enhancement as well as dose reduction in the medium using high-energy electron beams. These effects provide dose distribution with arbitrary shapes for use in radiation therapy.}, keywords = {Electron Beam,Magnetic Field,Radiation Therapy}, url = {https://ijmp.mums.ac.ir/article_2630.html}, eprint = {https://ijmp.mums.ac.ir/article_2630_2cbce93288e60a364b15d48ff9bf26ef.pdf} } @article { author = {Tavakol, Marzieh and Karimian, Alireza and Mostajab Aldaavati, Sayyed Mojtaba}, title = {Dose Assessment of Eye and Its Components in Proton Therapy by Monte Carlo Method}, journal = {Iranian Journal of Medical Physics}, volume = {11}, number = {1}, pages = {205-214}, year = {2014}, publisher = {Mashhad University of Medical Sciences}, issn = {2345-3672}, eissn = {2345-3672}, doi = {10.22038/ijmp.2014.2631}, abstract = {Introduction Proton therapy is used to treat malignant tumors such as melanoma inside the eye. Proton particles are adjusted according to various parameters such as tumor size and position and patient’s distance from the proton source. The purpose of this study was to assess absorbed doses in eyes and various tumors found in the area of sclera and choroid and the adjacent tissues in radiotherapy while changing most important proton therapy parameters such as moderators thickness (1.5-1.9 cm), exposure radius (0.5-0.8 cm), and proton energy beam (53.5-65 MeV). Materials and Methods A proton therapy system of Laboratori Nazionali del Sud-INFNwas simulated by Monte Carlo method. Moreover, the eye and its components were simulated using concentric spheres. To obtain a more accurate results, real density of eye components such as cornea and lens, were applied for simulation. Then, the absorbed dose of eye and eye tumor, in choroid and sclera areas, were calculated by Monte Carlo method. Results The absorbed dose in tumoral region of eye was calculated to be about 12.5 ±0.006Gy in one day with energy 62 MeV for a therapy session, which is suitable for treatment. However, normal eye cells received at most 11.01 Gy which is high. Conclusion The amount of absorbed dose in tumoral cells is noticeable. Therefore, accurate treatment planning, patient immobility and fine calibration of proton-therapy system and its simulator are very important to reduce the absorbed dose of healthy cells.}, keywords = {Absorbed Dose,Melanoma,Monte Carlo Method,Proton Therapy}, url = {https://ijmp.mums.ac.ir/article_2631.html}, eprint = {https://ijmp.mums.ac.ir/article_2631_ea82c340578ad3d8443bfaa12563ba2d.pdf} } @article { author = {Younessi Heravi, Mohamad Amin and Khalilzadeh, Mohamad Ali}, title = {Designing and Constructing an Optical System to measure Continuous and Cuffless Blood Pressure Using Two Pulse Signals}, journal = {Iranian Journal of Medical Physics}, volume = {11}, number = {1}, pages = {215-223}, year = {2014}, publisher = {Mashhad University of Medical Sciences}, issn = {2345-3672}, eissn = {2345-3672}, doi = {10.22038/ijmp.2014.2632}, abstract = {Introduction Blood pressure (BP) is one of the important vital signs that need to be monitored for personal healthcare. Arterial blood pressure is estimated from pulse transit time (PTT). This study uses two pulse sensors to get PTT. The aim of this study was to construct an optical system and to monitor blood pressure continuously and without cuff in people with different ages. Materials and Methods To measure blood pressure changes, two infrared optical transmitters were used at the distances of 5 mm to the receivers. Output of the optical receivers was inserted in analog circuits. PTT was defined as the time between the two peaks of pulse signals by the software. Signals were measured continuously through a serial network communication. An external personal computer monitored measured waveforms in real time. BP was related to PTT and the relationship coefficients were calculated at different physical activities. After determining the linear correlation coefficients for each individual, blood pressure was measured by the cuff and the PTT method and the results were compared. Results PTT computed between the two peaks of wave pulses was strongly correlated with systolic blood pressure (R=0.88±0.034) and the diastolic blood pressure (R=0.82±0.058). Systolic blood pressure (SBP) was measured more accurately than the diastolic blood pressure (DBP). The results of SBP showed that the maximum difference and the error percentages between the cuff method and the present method were 7.98±2.88 and 6.33±2.51%, respectively. Moreover, the maximum difference and the percentage errors between the cuff method and the present method of DBP were 10.13±3.82 and 10.97±3.89%, respectively. Conclusion Monitoring blood pressure with the designed system can be recommended as a useful method to indicate cardiovascular diseases and used for personal healthcare purposes.  }, keywords = {Blood Pressure Monitoring,Optical System,Pearson Correlation,Pulse Wave}, url = {https://ijmp.mums.ac.ir/article_2632.html}, eprint = {https://ijmp.mums.ac.ir/article_2632_eefd362826788210b6aea1631c37320b.pdf} }