Estimation of skeletal plutonium levels based on DTPA-induced radionuclide excretion in feces: possible application to man

A new approach to the estimation of plutonium (Pu) levels in the skeleton based on measurements of Pu excretion in the feces following treatment with diethylenetriaminepentaacetic acid (DPTA) is presented. The estimation method was tested in groups of mice receiving either 0.5 or 5 μ Ci/kg of 239Pu(IV) citrate, and treated with Na3(CaDTPA) starting either at 1 hr or 24 hr after Pu administration. In the case of DTPA treatment begun at 1 hr, the ratio of skeletal Pu content at 1 hr, S, to DTPA-induced fecal excretion of Pu, F, was 1.08 +- 0.03. When DTPA treatment was begun at 24 hr, the corresponding S/F ratio was 1.68 +- 0.08 and was independent of Pu injection level. In the mouse, therefore, a reasonable estimate of skeletal Pu content just prior to treatment can be determined from the amount of Pu measured in the feces following DTPA therapy. Application of this method to species other than the mouse is examined, with anticipation that the method might be applicable to cases of human exposure. (author)