IMMUNOSCINTIGRAPHY OF PEDIATRIC RHABDOMYOSARCOMA WITH RADIOLABELED ANTIMYOSIN MONOCLONAL-ANTIBODIES

Over the past decade, a number of radiopharmaceuticals, including gall ium-67 citrate, thallium-201 chloride, and technetium-99m methylene di phosphonate, have been tentatively applied for the detection of soft t issue sarcomas, These methods have appreciable sensitivity, but poor s pecificity. A promising approach consists in the use of radiolabelled antibodies raised against tumor-associated structures. In this study w e have evaluated the clinical utility of the radiolabelled antimyosin monoclonal antibody R11D10 to detect rhabdomyosarcoma (RMSA) in paedia tric patients. Nine patients with primary RMSA and four with no eviden ce of disease (NED) underwent immunoscintigraphy. Among the patients w ith primary tumors, seven had positive scans. No false-positive result s were observed in patients with NED. In our experience, therefore, im munoscintigraphy with radiolabelled antimyosin monoclonal antibody R11 D10 is an effective and safe method to image RMSA lesions.