In vivo applications of X-ray fluorescence in human subjects

X-ray fluorescence has been used to measure several elements noninvasively within living human subjects. Some description is given of the constraints imposed by this rather unusual form of analysis together with a brief listing indicating the range of elements for which such analyses have been developed. Measurements of two elements are then presented in more detail. Lead is measured in bone and has become a well-established tool in continuing research into the long term effects of lead. Strontium is also measured in bone and, although presently not in widespread use, offers the potential for essential information in the study of the reported benefits of strontium supplementation.