Estimation of Total Skeletal Content of Plutonium and Am-241 From Analysis of a Single Bone

摘要

The skeleton is one of the major retention sites for internally deposited actinides. Thus, an accurate estimation of the total skeleton content of these elements is important for biokinetic modeling and internal radiation dose assessment. Data from 18 whole-body donations to the US Transuranium and Uranium Registries with known plutonium intakes were used to develop a simple and reliable method for estimation of plutonium and Am-241 activity in the total skeleton from single-bone analysis. A coefficient of deposition K-dep, defined as the ratio of actinide content in the patella to that in the skeleton, was calculated for Pu-239, Pu-238, and Am-241. No statistical difference was found in K-dep values among these radionuclides. Variability in K-dep values was investigated with relation to skeleton pathology (osteoporosis). The average K-dep of 0.0051 +/- 0.0009 for the osteoporotic group was statistically different from K-dep of 0.0032 +/- 0.0010 for nonosteoporotic individuals. The use of K-dep allows for rapid estimation of the total skeletal content of plutonium and Am-241 with up to 35% uncertainty. To improve accuracy and precision of total skeleton activity estimates, regression analysis with power function was applied to the data. Strong correlation (r(2) > 0.9) was found between Pu-239, Pu-238, and Am-241 activities measured in the patella bone and total skeleton activity. The results of this study are specifically important for the optimization of bone sample collection for US Transuranium and Uranium Registries partial-body donations.