131I-Iobenguane (131I-Metaiodobenzylguanidine, 131I-MIBG) is a generic Radiopharmaceutical indicated for use in the detection and therapy of primary or metastatic pheochromocytoma and out of adrenals, neuroblastoma and paraganglioma. It can be used for Imaging of neuroendocrine tumors of gastro-entero-pancreatic tract and medullary thyroid carcinoma. In cardiac diagnostics, it finds applications in the diagnosis of myocardial ischemia and cardiomyopathies. At higher doses it can be used for treatment of these pathologies. MIBG images the adrenal medulla (not the adrenal cortex) and sympathetic nervous tissue.

A new form was recently launched under the name Azedra™ for the potential treatment of neuroendocrine tumors, such as neuroblastoma and pheochromocytoma. Azedra differentiates from generic 131I-MIBG as a highly pure 131I-labeled compound for which a difference in Imaging quality and therapeutic advantage is claimed. Azedra was approved by the FDA as a treatment for patients with paraganglioma or pheochromocytoma age 12 and older in July 2018.

Target/Mechanism: Adrenergic tissues

Leading Emitter: beta electrons (β)