Conversion Coefficients for Radiological Protection Quantities for External Radiation Exposures

摘要

Abstract-This report gives fluence to dose conversion coefficients for both effective dose and organ absorbed doses for various types of external exposures, consistent with the 2007 Recommendations of the ICRP (ICRP, 2007). These coefficients were calculated using the official ICRP/ICRU computational phantoms (ICRP, 2009) representing the Reference Adult Male and Reference Adult Female (ICRP, 2002), in conjunction with Monte Carlo codes simulating the transport of radiation within the human body such as EGSnrc, FLUKA, GEANT4, MCNPX, and PHITS.The incident radiations and energy ranges considered were external beams of mono-energetic photons of 10 keV-10 GeV, electrons and positrons of 50 keV-10 GeV, neutrons of 0.001 eV-10 GeV, protons of 1 MeV-10 GeV, pions (negative/positive) of 1 MeV-200 GeV, muons (negative/positive) of 1 MeV-10 GeV, and helium ions of 1 MeV/u-100 GeV/u.For the simulations, idealised whole-body irradiation geometries were considered. These included unidirectional broad parallel beams along the antero-posterior, postero-anterior, left lateral and right lateral axes, and 360° rotational directions around the phantoms' longitudinal axis. Fully isotropic irradiation of the phantoms was also considered.Simulations were performed specifically for this report by members of the Task Group. For quality assurance purposes, data sets for given radiations and irradiation geometries were generated by different groups using the same reference computational phantoms but different Monte Carlo codes.From the simulations, the absorbed dose to each organ within the reference phantoms was determined. The fluence to effective dose conversion coefficients were derived from the obtained organ dose conversion coefficients, the radiation weighting factor wR and the tissue weighting factor wT, following the procedure described in ICRP Publication 103 (ICRP, 2007).