D. Elmore, Purdue University

M.H. Bhattacharyya, N. Sacco-Gibson, D.P. Peterson, Argonne National Laboratory

Nuclear Instruments and Methods 52 (1990) 531-535

The use of 41Ca (half-life 1x 10^5 yr) as a tracer for studying calcium metabolism in living systems is compared to the shorter-lived radionuclides 45Ca (165 d) and 47Ca (45 d) and the stable isotopes 42Ca and 44Ca. The feasibility of using accelerator mass spectrometry (AMS) measurements of 41Ca for studying multi-year calcium resorption in humans was tested as part of a companion study that used 4sCa to measure the effects of dietary cadmium on calcium metabolism in dogs. It was shown that 41Ca resorbed from prelabeled bones correlates well with 45Ca for a period of 28 weeks. The advantage of 41Ca is that, even with a negligible radiation dose, it can be measured by AMS long after the 45Ca becomes unmeasurable.