Application of the NCRP wound model to some LANL plutonium wound cases

Full text: In collaboration with the International Commission on Radiological Protection, the U. S. National Council on Radiation Protection (NCRP) has published Report Number 156, which describes a consensus biokinetic model for radionuclides in wounds. The model is comprehensive and includes experimental data from 48 radioactive elements. The structure of the compartmental model was designed using chemical and pathobiological concepts. Although the model is believed to be a significant improvement for describing the biokinetics of radionuclides in wounds, it was of necessity developed using data from experimental animal studies. It is therefore important that the model be validated using data from human exposure cases. This paper describes the application of the NCRP wound model to two wound cases from the Los Alamos National Laboratory. For both test cases, the parameter sets for each of the seven default retention categories of the model were fitted sequentially to the Pu urine data, which extended to at least 3000 days after a single known wound exposure. In one case, the Strong Soluble category provided the best fit (normalized chi-squared = 1.08); for the other case the Avid Soluble category was best (chi square = 1.68). It is important to note that both the Strong and Avid categories were identified in the NCRP report as defaults for plutonium retention in wounds. This has been affirmed by these analyses. Studies of the effects of varying selected transfer rates within the wound model will also be described. (author)