The excretion of thorium and thorium daughters after thorotrast administration

Abstract

The thorium and thorium daughter product content of excreta were analyzed for the early period after administration of 75 and 60 ml of Thorotrast (ThCO2) respectively to two human subjects. Autopsy tissues from four Thorotrast patients were analyzed for Th. Less than 1% of the administered Th was excreted in the early period and a biologic half-life of more than 400 years was calculated. Ra228 excretion is modified by the physical nature of the injected material and it is estimated that 0.026% of the body content is excreted per day in the "steady state". Ra224 excretion at the rate of 2.6% of the body content per day after a state of transient equilibrium was established. The total body gamma ray measurements and gamma ray distribution studies gave results similar to the excretion results of the radium isotopes Dosage calculations were made for the organs of maximum Th deposition, i.e., liver, spleen, bone marrow, and lung.