VI. A Survey of the Metabolism of Caesium in Man

Abstract

Present knowledge of the metabolism of Cs in man is reviewed; data on stable Cs in autopsy materials, as well as on radioactive Cs both in autopsy material and in vivo are considered. Cs is distributed widely throughout the body but is mainly in the soft tissues; the concentration in rib appears to be higher than in cortical bone (femur). Uptake of caesium chloride from the gastrointestinal tract is rapid and essentially complete. Excretion is principally via the urine, but there is a continuing loss in the feces whether the administration was by ingestion or intravenous injection. The urinary/fecal excretion ratio ranges from less than 2 to more than 10 among individuals, but is reasonably constant in any one subject. The whole-body retention of Cs can be expressed by a 2-component exponential function of time; some 6-15 (mean about 10%) of a single oral dose is excreted with a short half-life (1-2 days), but the major part has a half-life between 50 and 150 (mean 110 days) with isolated cases reported of up to 200 days. This variability may account to a large extent for the considerable range of fall-out Cs 137 contents which were reported.