The use of 3,4-dihydroxy-6-[(18)F]-fluoro-L-phenylalanine ((18)F-FDOPA) with positron emission tomography initially centered on studying central motor disorders and evaluating patients with Parkinsonian symptoms, based on its uptake into presynaptic dopaminergic terminals in the putamen and caudate nuclei of the brain. The roles of this tracer have since expanded to include monitoring disease progression, potentially contributing to drug development, and even questioning the current gold standard for making the diagnosis of Parkinson's disease. As with some other amino acids, (18)F-FDOPA has also been effective for visualizing brain tumors, either at time of diagnosis or when monitoring for recurrence, with high sensitivity and overall accuracy. (18)F-FDOPA may be especially useful for imaging patients with low-grade gliomas, as well in the evaluation of patients with neuroendocrine tumors such as carcinoid and pheochromocytoma, in which its role as a precursor for amine neurotransmitter/neurohormones serves as a basis for its differential uptake.