Technetium-99m APD compared with technetium-99m MDP as a bone scanning agent

The authors have investigated the possibilities of technetium-99m-(-3-aminohydroxypropylidene)-1-1-bisphosphonate ([/sup 99m/Tc]APD) as a bone scanning agent in 14 normal subjects and 28 patients. Similar studies in the same normal subjects and patients were carried out with /sup 99m/Tc-methylene-bisphosphonate ([/sup 99m/Tc]MDP). The compounds were labeled with /sup 99m/Tc by means of an electrolytical method; the free pertechnetate content was always under 1%. The [/sup 99m/Tc]APD T1/2 of the third component of the disappearance plasma curve in six normal subjects was 152 +/- 46 min (mean +/- s.d.), while the 24-hr whole-body retention (WBR) was 17.6% +/- 4.6. The [99mTc]MDP value of the 24-hr WBR was 28.6% +/- 3.9. The bone/soft-tissue ratio (B/ST) was investigated in eight control subjects on the eleventh thoracic and the fourth lumbar vertebrae. The B/ST ratios were similar for both APD and MDP studies. In 28 patients with suspected bone metastasis or primary bone disease, bone scintigraphy was carried out; both compounds showed similar findings and the same number of positive results. In five of these patients, the lesion/normal bone ratio was determined with values of 4.6 +/- 2.0 in APD studies and 4.8 +/- 2.3 with MDP. APD was also used in 126 patients; no adverse reactions were observed. The APD dose used i.v. for bone scanning was 200-fold less than those employed by mouth per day, for the treatment of bone disease for long periods. In our experience, APD appears to be an adequate agent for bone scintigraphy