Photon dose coefficients for idealized external exposures calculated using ICRP-143 pediatric reference phantoms

Recently, the International Commission on Radiological Protection (ICRP) released pediatric reference computational phantoms in ICRP Publication 143, but has not released pediatric dose coefficients (DCs) for idealized external exposures. This study produced a comprehensive dataset of photon DCs by conducting Monte Carlo dose calculations using Geant4 and the ICRP-143 phantoms. The dataset includes organ/tissue absorbed dose coefficients per fluence (DCT, pGy·cm 2 ) for 30 radiosensitive organs/tissues and effective dose coefficients per fluence (DCE, pSv·cm 2 ) for six irradiation geometries (AP, PA, LLAT, RLAT, ROT, ISO) and 55 monoenergetic photon energies from 10 keV to 10 GeV, consistent with the adult DCs of ICRP Publication 116. We compared the pediatric DCs with the ICRP-116 adult DCs and found significant age dependency in both DCT and DCE. Most pediatric DCT and DCE values were greater than adult values at low energies (<10 MeV) but lower at higher energies. For pediatric DCE, the maximum deviations were 4.2-fold at 0.01 MeV for the newborn in AP geometry and 3.0-fold at 10 GeV for the newborn in ISO geometry. These results indicate the necessity of age-dependent DCs for radiological protection of members of the public.