Doses to the Embryo and Fetus from Intakes of Radionuclides by the Mother

Abstract

In its Publications 56, 67, 69, 71, and 72, ICRP has provided age-specific biokinetic models and, using those models, compiled dose coefficients (doses per unit intake) for intakes of radionuclides by members of the public. Committed effective doses for the inhalation or ingestion of radionuclides by workers who are occupationally exposed were given in Publication 68 based on the most recent dosimetric and biokinetic models for adults. Additionally, a compilation of dose coefficients for both workers and members of the public has been issued on a CD-ROM. The present report complements that series by addressing doses to the embryo/fetus after intakes of radionuclides by a female member of the public or a female worker, before or during pregnancy. Ingestion and inhalation of selected radionuclides of the 31 elements for which age-dependent biokinetic models were provided in the previous reports are considered. These elements are H, C, S, Ca, Fe, Co, Ni, Zn, Se, Sr, Zr, Nb, Mo, Tc, Ru, Ag, Sb, Te, I, Cs, Ba, Ce, Pb, Po, Ra, Th, U, Np, Pu, Am, and Cm. New biokinetic and dosimetric models for calculating doses to the developing embryo and fetus are developed and used in conjunction with the models for infants, children, and adults presented in the previous reports. The models used take account of transfer of radionuclides across the placenta, distribution and retention of radionuclides in fetal tissues, growth of the fetus, and photon irradiation from radionuclides in the placenta and maternal tissues. Human and animal data are used as available in the development of these models. Intake scenarios comprising single or continuous maternal intakes are taken into account in the compilation of effective dose coefficients following ingestion or inhalation of the radionuclides considered. A CD-ROM with more comprehensive information on doses from inhalation of different particle sizes, tissue doses, and doses at various times after birth has been developed concurrently with the report and will be available shortly. The report does not consider doses to the offspring due to intakes of radionuclides in maternal milk and external irradiation from the mother's body after birth. The radiation sensitivity of the offspring is not discussed.