An octreotide scan or octreoscan is a type of scintigraphy used to find carcinoid and other types of tumors and to localize sarcoidosis. Octreotide, a drug similar to somatostatin, is radiolabeled with indium-111, and is injected into a vein and travels through the bloodstream. The radioactive octreotide attaches to tumor cells that have receptors for somatostatin. A radiation-measuring device detects the radioactive octreotide, and makes pictures showing where the tumor cells are in the body. It is also called somatostatin receptor scintigraphy and SRS.