Diagnosis of pheochromocytoma by 131I-MIBG scintigraphy

: Between February, 1984, and June, 1988, 131I-metaiodobenzylguanidine (131I-MIBG) scintigraphy was performed on 48 patients with suspected pheochromocytoma at our hospital. Whole body image and/or spot images were obtained 24, 48 and 72 hours after injection of 0.5 mCi of 131I-MIBG. In 10 of 12 patients with surgically proven pheochromocytoma, 131I-MIBG was accumulated in the primary and metastatic tumor. 131I-MIBG scintigraphy was negative in 2 patients. One case of renal cyst had the accumulation of 131I-MIBG but the disease could be confirmed. By 131I-MIBG scintigraphy sensitivity was 83% (10/12), and specificity was 97% (35/36). Heart intensity was much higher in patients with nonpheochromocytoma than those with pheochromocytoma. Thus 131I-MIBG scintigraphy proved to be safe, non-invasive and specific in the diagnosis of pheochromocytoma.