99Tcm (V) DMSA and 111In Pentetreotide in the Detection of Malignancies

The aim of the study was to reveal primary and/or secondary foci that are clinically occult in suspected, positive for somatostatin-receptors tumours, and to evaluate their tumouricidal behaviour. Among 25 patients (a) 4 suffered from medullary thyroid carcinoma, (b) 6 had small-cell lung carcinoma, (c) 7 had pheochromocytoma, and (d) 8 had breast cancer. 185 MBq (5mCi) 99T cm (V) DMSA (Nucl Research Centre «Demokritos», Athens) and 185 MBq (5mCi) 11In Pentetreotide (OctreoScan 111, Mallinckrodt Medical B.V., Petten) were both injected to each patient (3-4 days time interval between the two examinations).99Tcm (V) DMSA scintigraphy was carried out 2.5 and 5 hrs after i.v. application. 111In Pentetreotide static images were obtained 5 and 18 hrs (delayed scans for comparison) after i.v. application. According to the results: (a) both radiopharmaceuticals showed higher sensitivity than do conventional imaging techniques, (b) medullary carcinoma showed in all cases a positive 99Tcm(V) DMSA scan, while small cell lung carcinoma a positive in all cases Pentetreotide scan. The examination is easy to perform and safe.