Somatostatin Receptor Scintigraphy for the Diagnosis of Neuroendocrine Tumors

Neuroendocrine cells throughout the body express somatostatin receptors. These receptors are generally overexpressed on neuroendocrine tumor cells. Octreotide, a somatostatin analogue, has a high affinity for a population of somatostatin receptors on neuroendocrine cells. By radiolabeling octreotide or other analogues, scintigraphy can localize tumors based on the abnormal density of somatostatin receptors expressed by tumor cells versus background. Currently, somatostatin receptor scintigraphy is used to localize carcinoid tumors, islet cell tumors, pheochromocytomas and paragangliomas. New applications for somatostatin receptor scintigraphy await the development of receptor subtype-specific analogues and additional radioligands.