99Tcm-MDP and 99Tcm-DPD in pathologic bone lesions. A visual and quantitative comparison.
The efficiency of 99Tcm-methylene diphosphonate (MDP) and 99Tcm-dicarboxypropane diphosphonate (DPD) to detect pathologically increased bone uptake was evaluated both by computed quantitative intra-individual and visual inter-individual comparison. Twelve patients with altogether 44 metastases in ribs and lumbar vertebrae were evaluated quantitatively. The lesion to normal bone ratio (mean +/- SD) was, with MDP, 2.9 +/- 1.6 and with DPD 2.4 +/- 1.2 (p less than 0.001), and the normal bone to soft tissue ratios with MDP 8.5 +/- 5.0 and with DPD 9.4 +/- 6.1 (NS). Visual analysis of 162 patients with 334 focal lesions showed no significant difference between two MDP preparations and one DPD preparation. Visual and quantitative comparison in the three most common malignancies studied (breast, prostatic, and lung carcinoma) gave the same result. Because the lesion to normal bone ratios were high with both agents, and there was no significant difference on visual analysis, both radiopharmaceuticals are considered to be relevant bone seeking agents and the difference between MDP and DPD is only academic and not of practical value.