Determination of lesion to normal bone uptake ratios of skeletal radiopharmaceuticals by QARG (quantitative autoradiography).

An animal model was developed to determine the ratio of uptake of different bone seeking radiotracers in skeletal lesions relative to normal bone in rats by dual tracer quantitative autoradiography (QARG). The lesion to normal bone uptake ratios (L/NB ratios) of 99mTc-MDP, 99mTc-HDP and 99mTc-DMAD were compared using 153Sm-EDTMP as an internal standard. The results from these studies demonstrated that the L/NB ratio of 99mTc-DMAD was an average of 54 and 71% higher than 99mTc-MDP and 99mTc-HDP, respectively and 79% higher than measured for 153Sm-EDTMP.