Due to intensive use of multileaf collimators (MLCs) in clinics, finding an optimum design for the leaves becomes essential. There are several studies which deal with comparison of MLC systems, but there is no article with a focus on offering an optimum design using accurate methods like Monte Carlo. In this study, we describe some characteristics of MLC systems including the leaf tip transmiss...

*Corresponding author: Dr. Asghar Mesbahi, Medical Physics Department, Medical School, Tabriz University of Medical Sciences, Tabriz, Iran. Fax: +98 411 3364660 Email: [email protected] Background: Prediction of the absorbed dose in irradiated volume plays an important role in the outcome of radiotherapy. Application of small fields for radiotherapy of thorax makes the dose calculation pr...

*Corresponding author: Dr. Mohammad Amin Mosleh-Shirazi, Department of Radiotherapy and Oncology, Shiraz University of Medical Sciences, Shiraz, Iran. Fax: +98 711 6474320 E-mail: [email protected] Background: The dose rate distribution delivered by a low dose rate 137Cs pellet source, a spherical source used within the source trains of the Selectron gynecological brachytherapy system, was inv...

background: the monte carlo (mc) method is not only used for dose calculations around brachytherapy sources but also for benchmarking treatment planning systems (tps) calculations. materials and methods: three 60co sources of gzp6 brachytherapy unit were simulated using mcnp4c mc code. the radial dose functions were calculated by mc method and gzp6 tps and were compared. results: there was a go...

background: in treating patients with radiation, the degree of accuracy for the delivery of tumor dose is recommended to be within ± 5% by icru in report 24. the experimental studies have shown that the presence of low-density inhomogeneity in areas such as the lung can lead to a greater than 30% change in the water dose data. therefore, inhomogeneity corrections should be used in treatment pla...

in this study, a general theoretical model to foresee and calculate the current-voltagecharacteristics in a plateau zone and the associated efficiency of the neutron detector (sensitivity) is presented. this study is to complete the previous studies in this field. the model also considers electric field distortion resulting from the charge collection effect. the characteristics curve is obtaine...

introduction: gamma knife is an instrument specially designed for treating brain disorders. in gamma knife, there are 201 narrow beams of cobalt-60 sources that intersect at an isocenter point to treat brain tumors. the tumor is placed at the isocenter and is treated by the emitted gamma rays. therefore, there is a high dose at this point and a low dose is delivered to the normal tissue surroun...

Introduction:  In  this  study,  we  utilized  the  MCNP4C  Monte  Carlo  code  to  quantitatively  evaluate  the  influence of crystal size and material on intercrystal scatter and parallax effects.   Materials and Methods:  For each of the 5 selected crystals (BGO, LSO, LYSO, LuAP, GSO), transport of  511  keV  photons  originating  from  a  point  source  and  incident  on  the  central  cry...