Retention Of Orally Administered Ca-47 In Man Measured In A Whole-Body Counter

A method is described for studying the retention of orally administered 47Ca using a whole-body counter. Two μCi 47Ca were given after an overnight fast together with calcium carrier as CaCl2 in water, and the retention was measured after one and two weeks. The error due to geometric and biologic variations was 1.7 per cent of the given dose. In 27 healthy subjects the retention of 47Ca one week after the administration was 35.7 ± 7.6 (S. D.) per cent of the given dose and after two weeks 29.3 ± 7.4 (S. D.) per cent.Key Words: 47Ca retentioncalcium absorptionwhole-body counter