PHEOCHROMOCYTOMA - DIAGNOSIS BY SCINTIGRAPHY USING IODINE 131 METAIODOBENZYLGUANIDINE

We summarize our experience using iodine 131 metaiodobenzylguanidine (I-131 MIBG) imaging in 24 patients with suspected pheochromocytoma and compare I-131 MIBG imaging with other imaging modalities such as computerized tomography and magnetic resonance imaging. Our results confirm the high sensitivity and excellent specificity reported from other centers experienced in I-131 MIBG imaging. This radiopharmaceutical permits noninvasive, safe, accurate detection of pheochromocytomas of all types. Iodine 131 MIBG scintigraphy is especially efficacious in the detection of extra-adrenal, recurrent, and metastatic tumors. We review precautions in the screening of patients for I-131 MIBG examination, imaging techniques, and drugs that interfere with tumor uptake of I-131 MIBG. Though I-131 MIBG imaging has some limitations, it deserves strong consideration whenever the diagnosis of pheochromocytoma is suspected.