The relation of radionuclide uptake by bone and rate of calcification has been studied in normal vertebrae and in vertebral metastases from cancer of the prostate. Specifically, the determination of 99Tcm-MDP uptake by radionuclide scanning and the estimation of calcium concentration of trabecular bone by dual-energy computed tomography have provided the means of obtaining a relation between these parameters which was similar to that found in an animal model, in which the dependence of radionuclide uptake on the rate of mineralization was established. This relationship has enabled the experimental findings to be extrapolated to those in patient studies and has shown that in sclerotic bone lesions, the increase in 99Tcm-MDP uptake accompanying the progression of the metastases was proportional to the rate of calcification.