Bone mineral content in the forearm measured by photon absorptiometry. Principles and reliability

A method for estimating total bone calcium is reported. The method is based on two-dimensional scanning photon absorptiometry on the distal part of the forearm. The following factors are investigated: precision of measurements on standards and human subjects; linearity; the effect of varying bone orientation; amount of fat and soft tissue; and the relation between weight and content of calcium and phosphate. The results show that the method is eminently suitable for rapid, easy, and atraumatic measurement of local bone calcium in vivo.