Whole-body autoradiography of 99Tcm-labelled pyrophosphate and related compounds in young rats.

The distribution of 99Tcm-labelled pyrophosphate in young rats was analysed by wholebody autoradiography and compared with those observed for 99Tcm-pertechnetate, 32P-labelled pyrophosphate and 85Sr-chloride. 99Tcm-labelled pyrophosphate was rapidly accumulated in bone and dentine and was similar to 32P-labelled pyrophosphate and 85Sr-chloride. The uptake of these substances in developing enamel was rather low in contrast to 99Tcm-pertechnetate, which had no affinity for bone.