Clinicians have long associated Parkinson's disease (PD) with personality traits such as seriousness and industriousness. In previous studies, patients with PD scored lower than matched orthopedic control subjects on novelty seeking, which is thought to be dopamine dependent. In this pilot study, 6-[18F]fluorodopa ([18F]dopa) uptake in the caudate and putamen was measured by PET in 9 patients with PD. Patients were also rated on three personality traits thought to be related to central monoamine function. Uptake of [18F]dopa in the left caudate, but not in other areas measured, was significantly correlated with novelty seeking. Results suggest that the personality traits long observed in PD patients may be partially mediated by striatal deficits in dopamine.