Age-Dependent Effective Doses for External Photons

Monte Carlo calculations of the effective dose, E, for external photons have been performed using anthropomorphic phantoms of six age groups: 0, 1, 5, 10 and 15 years, and adult. Twelve incident energies from 17 keV to 8.5 MeV were selected of each of five irradiation geometries: AP, PA, RLAT, ROT and ISO. The results are presented in the form of conversion factors correlating air kerma in free air with E. Since the classification of age groups corresponds to that considered for internal dose calculations, the conversion factors obtained here serve to assess doses to members of the public harmonising the external with the internal exposure situations. It was found that E increases generally with decreasing age, except for photons of 71 to 230 keV and AP geometry.