Biokinetic models for the behaviour of carbon-14 from labelled compounds in the human body: can a single generic model be justified?

The published data on the biokinetic behaviour of 27 14C-labelled compounds in humans or animals have been reviewed. Effective doses have been calculated for those compounds for which this information had not been published and doses have been compared to that calculated with the International Commission on Radiological Protection (ICRP) default model for carbon compounds of unknown composition. The compound-specific effective doses for a few natural human biochemical substrates are quite close to the ICRP default dose coefficient, but for the remainder of the compounds considered the doses are smaller by factors ranging from about 5 to 200. Comparison of the dosimetric data suggests that although the ICRP default model will overestimate the dose for very many compounds it could remain useful as a guide for general prospective radiological protection purposes. However, a comparison of the biokinetic information indicates that the ICRP default model would not be reliable for the interpretation of bioassay data.