Excretion and Retention of Radioactive Strontium in Normal Men Following a Single Intravenous Injection

Abstract

The faecal and urinary excretion-rates of strontium-85 following a single injection, in two normal adults, have been measured up to 140 days after the dose, while the retention, as observed by means of a whole-body counter, has been determined up to 1 year. It is shown that the retentions can be fitted to a power law or to a four-term exponential expression. The turnover of the dose is regarded as a three-stage process, (1) rapid excretion up to 20–30 days accounting for about 70 per cent of the dose, (2) an intermediate-rate process comprising about 15 per cent of the dose, (3) a chronic retention stage when the excretion is very small. The urinary-excretion ratio has been related to the body burdens by a single expression, and the dose to the bone is evaluated on the basis of a uniform distribution of radioactive strontium.