Techniques for determining the efficacy of treatment of osteoporosis.

Each of the presently available noninvasive methods used to determine the nature and degree of changes in skeletal mass has significant advantages and limitations. Dual photon absorptiometric techniques generally have a very low radiation dose. They are also less expensive to construct than other systems. However, they provide information only on a highly localized portion of the axial skeleton. Computed tomography offers significant potential advantages over other techniques, but requires further work for the solution of inherent technical problems. Similarly, considerable additional work is required for the Compton scattering technique; the technical problems associated with this are even more formidable. Neutron activation analysis permits the direct in vivo measurement of total calcium content of the body and hence, skeletal mass. However, while there is vast clinical and research experience with partial body and total body neutron activation, the techniques are generally not routinely available for application in clinical centers. The question as to whether DPA of the spine, or total body calcium measurement best reflects changes in bone mass after therapy has not been resolved.