Internal dose for molybdenum radionuclides based on a revised biokinetic model

Recent investigations with human volunteers showed that the model recommended by ICRP for the description of the biokinetics of molybdenum radionuclides is not able to describe some characteristic features, like the clearance from the transfer compartment and the urinary excretion profile. Therefore, a revision of the model was presented in a previous paper. In the current work, dose coefficients for ingestion of radionuclides of molybdenum from members of the public have been calculated according to the ICRP guidelines, but using the revised biokinetic model. The results obtained for the effective dose do not differ remarkably from the ICRP estimates. However, considerable deviations are observed for the equivalent dose to some individual organs; for example, the dose coefficient for colon after ingestion of 99Mo in solid form is about 7 times higher than the ICRP value, whereas for other organs the new estimates are about one tenth of the ICRP ones. This fact could be of importance with respect to deterministic effects to particularly radiosensitive organs.