INTERPRETATION OF BIOASSAY MEASUREMENTS USING DIFFERENT SYSTEMIC MODELS FOR PLUTONIUM

In vitro bioassay measurements for plutonium have been performed on a routine basis for many years. Since the biokinetic models have changed considerably and the dose limitation systems have become more restric tive, it is necessary to estimate the impact of these changes on the i nterpretation of bioassay measurements. This study is carried out for the plutonium systemic models proposed by the ICRP publications: ICRP- 30, ICRP-48, and ICRP-56, using the excretion functions proposed by La ngham, Durbin, and Jones. A quantitative comparison of dose estimates using the dose limitation systems proposed in the ICRP Publications 26 and 60 is also done. In order to evaluate the impact on the use of th e new ICRP respiratory tract model, a comparative study of intake and dose estimates, using the new and the ICRP-30 respiratory tract models , was also done for the case of inhalation of plutonium compounds. The se calculations are particularly important to provide means to compare doses when the occupational exposures lasted many years and the doses were assessed using different models and dose limitation systems. Sin ce some countries are in the process of changing the dose limitation s ystem from the recommendations of the ICRP-26 to the ICRP-60, or even from the ICRP-2 to the ICRP-26, a quantitative comparison of dose esti mates will be shown. In order to evaluate the impact on the use of the new ICRP respiratory tract model, a comparative study of intake and d ose estimates using the new and the ICRP-30 respiratory tract models w ill also be shown for the case of inhalation of plutonium compounds.