Distribution of natural thorium in the tissues of a whole body.

The distribution of thorium in the tissues of a whole body donor to the United States Transuranium and Uranium Registries is described. This case, identified by the USTUR as Case 0212, had two documented intakes of plutonium and americium from occupational accidents while employed at Hanford but no known occupational exposure to thorium. Concentrations of 239+240 Pu, 241 Am, and 232 Th in the tissues are compared and the distribution of these isotopes in this case is evaluated. The distribution data for 232 Th are compared to those from previous studies of thorium in human tissues resulting from environmental exposure and to an individual exposed to Thorotrast (colloidal ThO 2 ) in a medical diagnostic procedure. The 232 Th distribution data from this work are also compared against ICRP 30 and ICRP 69 models for the behaviour of thorium in the human body.