Use of stable48Ca in the clinical measurement of intestinal calcium absorption

Abstract

Summary Measurements of intestinal-calcium-absorption efficiency are fundamental for understanding calcium homeostasis in health and disease. Stable calcium isotopes are attractive tracers for such measurements, to avoid excessive radiation exposure to the subject and permit serial studies at short intervals. To realize this, we found it necessary to improve the sensitivity and precision of existing thermal neutron activation analyses for⁴⁸Ca. This report describes the details, sensitivity, precision, and accuracy of the improved method, and gives the results of studies in which intravenous⁴⁸Ca was used in conjunction with oral⁴⁷Ca to measure intestinal-calcium-absorption efficiency in patients.