Comparison between Modelling and in vivo Measurements of natural Radionuclides in Man for Proof of the Biokinetic Model and for Reconstruction of the Radiation Exposure

A research program was started to improve the reliability in dose evaluations of incorporated natural radionuclides for members of the public and occupationally exposed persons. The major aim of this project is the improvement of retrospective radiation exposure by incorporation and excretion measurements combined with a biokinetic modelling. As the exposure pattern and the body activity of the radionuclides are known, the biokinetic model can be tested. In this study the concentrations of natural U in the urine samples of a Finnish family with five members were determined. Correspondingly, a theoretical biokinetic modelling of natural uranium incorporations for the members of the family were performed with the aid of personal follow-up interviews. The ICRP biokinetic compartmental model and the age-dependent transfer rates between compartments for U were used to model the distribution, retention and excretion of radionuclides for each member of the family. Through the comparison between the measured and calculated data, the biokinetic model can be verified and improved. Thus, an optimal model of the metabolic behaviour for an ICRP reference man and members of the public can be achieved. (Author) 18 refs