The relation of radionuclide uptake by bone to the rate of calcium mineralization. I: Experimental studies using 45Ca, 32P and 99Tcm-MDP.

The study of the uptake of radionuclides by bone has been undertaken in a mouse tail graft model using 45Ca, 32P and a routine bone scanning agent 99Tcm-MDP, together with serial calcium determinations. The model provided an experimental system in which the calcium mineral content and the rate of mineralization both changed progressively throughout its development. A significant linear correlation was found between 45Ca and 32P uptake and the rate of calcium mineralization, which held for all stages of the graft's growth. Both radiotracers therefore accurately reflected the calcium mineral deposition. In the case of 99Tcm-MDP, the correlation with mineralization rate only applied for the most active growth period of the graft when the rate was increasing. For all radiotracers, the peak in bone uptake corresponded to the maximum in mineralization rate.