EVALUATION THE SUCCESS OF I-131-MIBG SCINTIGRAPHY IN PATIENTS WITH PRIMARY, RECURRENT OR METASTATIC PHEOCHROMOCYTOMA AND NEUROBLASTOMA

The aim of this study was to evaluate the success of I-131-Metaiodobenzylguanedine (MIBG) imaging in patients with primary, recurrent or metastatic pheochromocytoma and neuroblastoma. Fourteen patients with pheochromocytoma and 21 patients with neuroblastoma, a total of 35 patients were included in the study. After iv injection of 0.5 mCi/1.72 body surface I-131-MIBG, the anterior and posterior spot images of whole body were acquired at 24., 48. and 72. hours. The scintigraphic results were compared to ultrasonography, computed tomography (CT), magnetic resonance imaging (MR), and surgical-pathological results. The sensitivity of I-131-MIBG in detection of primary, residual, recurrent and metastatic lesions of pheohromocytomas and neuroblastomas, was found to be 100% and 72% and the specificity was 77% and 90 %, respectively. Two false positive seans due to thymus hyperplasia decreased the specificity of the test in patients with pheochromocytoma. The lower sensitivity of the test for neuroblastoma was due to the false negative seans in patients with tumors including large necrotic tissue or tumors which are less than 2 cm in diameter. In conclusion, MIBG scintigraphy is a sensitive and complementary test when used with CT and MR and is able to detect the distant metastases and recurrence with a single and safe procedure.