ICRP 메시형 표준 전산팬텀의 물리모델에 의한 흡수선량 계산

Abstract

Physics models in Geant4 account for physical interaction on dose calculations. The objective was to investigate the effect of physics models with monte carlo simulated the adult mesh-type reference computational phantom for evaluation. For idealized external irradiation by an Varian linac in 6 MV and 10 MV photons, organ or tissue absorbed doses were computed for phantom released in ICRP (International Commission on Radiological Protection) Publication 145, which calculated with the Geant4 monte carlo code. The multi threaded design were done and processes used in electromagnetic physics lists Livermore and Penelope were set to calculate this phantom for 8 organs or tissues. The phantom was assumed to be placed in a vacuum and irradiated by broad parallel beams in AP (anterior-posterior) direction, incident to the phantom. 10 histories were simulated for each test. The association between physics models was analyzed by using independent t-test. The values of absorbed doses obtained with Livermore model in 6 MV photon ranged from 8.663E-05 to 2.030E-04 pGy for pelvis of cortical and spongiosa, small intestine wall, rectum wall, prostate, skin of trunk, urinary bladder wall, and urinary bladder contents. With Penelope, the values of absorbed dose were from 8.634E-05 to 2.050E-04 pGy. The results were not significantly different for the test (p>0.05) when analysis is implemented with two physics models. For 10 MV, there were found to be no statistically significant difference (p>0.05). These data support the idea that two electromagnetic models can be compatible in specific simulation applications.