COMPARATIVE METABOLISM OF RADIONUCLIDES IN MAMMALS .4. RETENTION OF SILVER-110M IN MOUSE RAT MONKEY AND DOG

Radiosilver (110mAg) was administered to mice, rats, monkeys, and dogs by oral and intravenous routes and also intraperitoneally to mice and rats. Retention as a function of time was determined by periodic assay in 4π liquid scintillation detectors. The data were adequately described by exponential expressions. Ninety per cent or more of oral doses were not absorbed. In all routes of administration more than 90% of the silver excreted was in the feces. A parabolic relation between body weights and estimated equilibrium levels in small animals was extrapolated to man. From such estimates an MPCW value of 1.8 nCi/cm3 (when the whole body is the critical organ) was derived. The ICRP value of 0.3 nCi/cm3 for the lower large intestine is still the limiting value. © 1968 Health Physics Society.