Molecular imaging of gastroenteropancreatic neuroendocrine tumors.

Somatostatin-receptor scintigraphy has become an obligatory molecular imaging method in the management of patients with neuroendocrine tumors when metastatic disease is suspected. Using positron emission tomography and new somatostatin analogues, sensitivity of somatostatin receptor imaging has further increased. With a combination of morphologic imaging methods, such as hybrid imaging by PET/CT, this method represents the method of choice in many centers and efforts are under way to translate somatostatin receptor imaging onto a cellular level by endoscopic confocal microscopy. Other clinically relevant functional pathways in neuroendocrine tumors that are accessible by PET imaging are glucose metabolism and amine precursor uptake and decarboxylation.