Dose coefficients for ICRP pediatric mesh-type reference computational phantoms under idealized external electron exposures

Abstract

In the present study, a comprehensive dataset of dose coefficients for idealized external electron exposures has been established using the newly released ICRP-156 pediatric mesh-type reference computational phantoms (MRCPs) in conjunction with the Geant4 Monte Carlo radiation transport code. The dataset comprises organ/ tissue-averaged absorbed dose coefficients for the 29 target organs and tissues which contribute to the effective dose, as well as effective dose coefficients, spanning three idealized, unidirectional, whole body irradiation geometries—antero-posterior (AP), postero-anterior (PA), and isotropic (ISO)—across 49 discrete electron energies from 10 keV to 10 GeV. Comparisons with the ICRP-145 adult MRCPs revealed significant age-dependent variations, with effective dose coefficients differing by up to ~38 times (5 years, PA, 50 keV), primarily due to variations in organ/tissue depths across different ages. Further comparisons with the ICRP-143 pediatric voxeltype reference computational phantoms (VRCPs) showed substantial differences below 10 MeV, with effective dose coefficients differing by up to four orders of magnitude, largely attributable to the inclusion of the thin skin target layer in the pediatric MRCPs. The findings of the present study are expected to serve as a valuable resource for optimizing radiological protection strategies for the pediatric population.