Although PD is considered predominantly as a motor disease caused by loss of dopaminergic neurons, multiple studies indicate that cholinergic dysfunction already starts in early PD and is crucial for the development of dementia in addition to motor symptoms.Because of its crucial role in CNS functioning and neurodegenerative disorders, including PD, it is of great importance to get a better understanding of the cholinergic functioning in the brain. Pathways of acetylcholine synthesis, transport and release provide possible targets for in vivo imaging of the cholinergic system. However,previous approaches are considered as indirect biomarkers of cholinergic terminal integrity because they measure both pre- and post-synaptic expressions. The novel vesicular acetylcholine transporter (VAChT) tracer [18F]Fluoroethoxy-Benzovesamicol ([18F]FEOBV) provides a more direct measurement of presynaptic cholinergic function. The use of [18F]FEOBV as a Positron Emission Tomography (PET) imaging marker of cholinergic innervations has, however, only been studied in healthy human volunteers and no data is available on patients.