PET imaging in neuroendocrine tumors: current status and future prospects.

Neuroendocrine tumors (NET) are relatively rare diverse group of tumors that possess several unique characteristics and occur most commonly in the gastrointestinal tract. An important feature of these tumors is that they express somatostatin (SST) receptors, and thus can be successfully targeted with specific radiolabeled SST receptor related compounds. This has led to the introduction of multitude of single photon emission computed tomography (SPECT) and positron emission tomography (PET) tracers, which have significantly improved the ability for imaging these neoplastic lesions with high spatial resolution in the abdomen and elsewhere in the body. The introduction of Gallium-68 labeled radiopharmaceuticals as viable PET agents have added a new dimension to the management of patients with NET by providing high quality images compared with planar or SPECT with single photon emitting preparations. (18)F-labeled DOPA has demonstrated impressive results in differentiating between focal and diffuse disease in hyperinsulinism of the newborn which appears to be of crucial clinical benefit and has altered the management of these patients significantly. With regard to other types of NET, the current experience with such agents is relatively limited and therefore prospective studies are required to further define the role of PET in this complicated group of patients.