Cholinergic neurons play an important role in neurotransmission within the central nervous system (CNS). They are involved in complex functions like memory, learning, recognition, attention, consciousness, regulation of sleep-wake cycles and maintenance of posture and gait. Cholinergic neuron degeneration in the neocortex and hippocampus of the CNS, is an important neurochemical change observed in several neurodegenerative diseases, including Parkinson's disease (PD) and Alzheimer's disease (AD). Therefore, assessment of the vesicular acetylcholine transporter (VAChT) as an important molecular target in the cholinergic circuit, has sparked interest in the development of radiotracers for studying this target in vivo. Preclinical studies show the VAChT tracer (-)-5- [18F]Fluoroethoxybenzovesamicol ([18F]FEOBV) to be potentially useful in detecting cholinergic lesions in vivo. A previous [18F]FEOBV PET study confirms that the tracer binds to VAChT with the expected in vivo human brain distribution. The use of [18F]FEOBV as a PET imaging marker of cholinergic innervations has, however, only been studied in healthy human volunteers and no data is available on patients.