Abstract
Urinary and fecal excretion of 144Ce was studied for 15 days following subcutaneous, intramuscular, intraperitoneal and intravenous injection of 144CeCl3 to the rat. From the third to the 15th day, the daily urinary excretion of 144Ce following all the routes of administration was expressed in the first approximation by a single exponential function, regardless of the difference of the routes. It means that the initial body burden of 144Ce can be estimated from the daily urinary excretion of 144Ce during this period using an identical formula.
Tissue distribution of 144Ce 15 days postinjection was also studied. After 15 days following subcutaneous and intramuscular injection, 57 and 38 percent of the injected 144Ce were found at the sites of injection, respectively. The transported 144Ce was deposited mainly in the liver and bone regardless of the routes of administration.
