Calculations of mean quality factors and their implications for organ-specific Relative Biological Effectiveness (RBE) in analysis of radiation-related risk in the atomic bomb survivors

清水 翔太*; 佐藤 達彦   ; 遠藤 章   ; 他5名*

Shimizu, Shota*; Sato, Tatsuhiko; Endo, Akira; 5 of others*

We calculate the mean quality factor based on LET distributions for representative organs and exposure scenarios of A-bomb survivors using PHITS simulations and the Q(L) relationship defined by ICRP, as well as the QF function defined by NASA. We also investigate the depth dependence of the mean quality factors in the ICRU sphere irradiated by mono-energetic neutrons. Both the results from the human phantom and from the ICRU sphere phantom suggest that the mean quality factors are largely independent of the organ type, and independent of depth, city and ground range when the contributions from the secondary gamma-rays are excluded from the neutron doses.