Scintigraphic Localization of Pheochromocytoma

Abstract

We used a new radiopharmaceutical agent, [¹³¹I]meta-iodobenzylguanidine ([¹³¹I]MIBG), to produce scintigraphic images of pheochromocytomas in eight patients. One day or more after injection, the only normal organ that displayed distinct concentrations of radioactivity was the urinary bladder. The [¹³¹I]MIBG was probably concentrated in adrenergic vesicles; in tissues where vesicles are numerous, such as pheochromocytomas, the radionuclide was retained for days.