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...

Introduction: Ophthalmic plaque radiotherapy using I-125 radioactive seeds in removable episcleral plaques is often used in management of ophthalmic tumors. Radioactive seeds are fixed in a gold bowl-shaped plaque and the plaque is sutured to the scleral surface corresponding to the base of the intraocular tumor. This treatment allows for a localized radiation dose delivery to the tumor with a ...