Radioiodine Metabolism in the Goat after Simultaneous Single and Daily Administration

Abstract

Simultaneous administration to goats of 2 radionuclides of iodine, I125 and I131, revealed no significant difference between the sum total of excretions in milk, urine, and feces after a single dose, compared with the average of the steady state excretions after daily ingestion. The experiments indicated that information from single doses of radioiodine can be extrapolated to predict the behavior of iodine under conditions of daily ingestion. Iodine125 was found to be of advantage in large animal experiments because of its long half-life. 57 days, and did not interfere with the determination of I131 when using a single channel analyzer. In turn,I125 could be separated from I131 by allowing Il31 to reduce to low levels by physical decay.