Fluorodeoxyglucose labeled with fluorine-18 (18F-FDG) is used to detect various tumors, and 18F-FDG PET has demonstrated high sensitivity (83%) for metastatic diseases of pheochromocytoma (PCC) and paraganglioma (PGL) in patients with mutations in the succinate dehydrogenase subunit B (SDHB) gene18, making it valuable for localizing metastatic PPGLs that are negative for mIBG19. The gene discussed is SDHB; the disease is paraganglioma.