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:  all of  the  people worldwide  are exposed  to  low levels  of  radiation. cancer induction  and  genetic disorders are among the hazards of low level exposure. in some cases, radiation close to hot springs is  higher than normal areas due to a high concentration and the decay products of ra-226. given the use of hot  springs by the general public  because  of their therapeutic p...

introduction radioactive materials naturally exist in the world. indeed, approximately 82% of human-absorbed radiation doses, which are out of human control, arise from natural sources of radiation including cosmic, terrestrial, and exposure through inhalation or ingestion. thus, the aim of the present study was to estimate health risk, as well as the effective and organ doses from naturally oc...

introduction polymer gel dosimeters offer a practical solution to 3d dose verification for conventional radiotherapy as well as intensity-modulated and stereotactic radiotherapy. in this study, egsnrc calculated and pagat polymer gel dosimeter measured dose profiles from single shot irradiation with 18 mm collimator of gamma knife in homogeneous and inhomogeneous phantoms were compared with eac...

background: the aim of this study was to measure137cs levels in soil and brick samples to set the baseline data and an indicator of fallout radioactivity for this part of the world. this study will help to probe, if there is any health threat posed by 137cs exposure to the residents of the area. materials and methods: twenty five samples of soil and 6 samples of bricks were collected from diffe...

gamma rays pose enough energy to remove electrons from atoms of absorbing material including human body and adversely affect human health. the external exposure of human beings to natural environmental gamma radiation normally exceeds that from all man-made sources combined. therefore, we monitored gamma dose rate in indoor environments and estimated corresponding annual effective dose in selec...

background: ionizing radiation is present in all environment of the earth’s surface, beneath the earth and in the atmosphere. human beings are exposed to external radiation from their surroundings naturally and also to internal radiation from food, water and air they consume. then, it is important to measure and develop knowledge about radiation. objective: this study is designed to evaluate th...

background: since 1996 the assessment of environmental gamma radiation dose in residential areas of iranian towns and cities has been accomplished for 10 counties. as a practical method and based on the results of a pilot study, in order to attribute the final results to the whole residential area of a town five stations were selected for every town. the location of individual station was studi...

premature chromosome condensation (pcc) appears to have a possible utility for biological dosimetry purposes. the pcc technique may be adapted for cases of suspicion of overexposure where sampling is performed at least one day after an accident. for this purpose, human blood samples were exposed in vitro to 60co up to 10 gy and the pcc technique was performed immediately after irradiation. anal...