Modern nuclear imaging for paragangliomas: beyond SPECT.

Paragangliomas are rare neuroendocrine tumors that may arise anywhere along the paraganglial system, with a high frequency of hereditary forms or multifocal disease. Most often, paragangliomas are benign and progress slowly, but metastases may occur in about 10% of patients. In this respect, nuclear imaging in combination with anatomic imaging may be required to fully delineate the extent of the disease. PET has been increasingly used in imaging paraganglioma, paralleled by great efforts toward the development of new tracers. Recent data indicate that the choice of PET tracers should be tailored to tumor localization and to the patient's genetic status. This article provides insight into the many PET radiotracers that are currently available and others that are still only under research and guides clinicians toward appropriate use in relation to genetic carrier status. In addition, this article provides nuclear medicine physicians with the background knowledge required for understanding relationships between imaging phenotypes and molecular genetics.