Positron Emission Tomography (PET) and Single Photon Emission. Computed Tomography (SPECT) highly contribute to the management of patients with movement disorders by measuring regional cerebral metabolism/blood flow and dopamine receptors. Imaging of the dopaminergic system is a powerful tool for distinguishing patients with neurodegenerative disorders, such as Parkinson's disease. Parkinsonism is most of the time caused by idiopathic Parkinson's disease. Considering the differences in therapeutic response and prognosis, differentiation between Parkinson's disease and "parkinsonism-plus syndromes" is important. Visualisation of pre- and post-synaptic D2 dopamine receptors by using receptor ligands helps to discriminate between Parkinson's disease and "parkinsonism-plus syndromes" as Parkinson's disease is a presynaptic disease. Early disease detection in subjects suspected at risk for developing Parkinson's disease has become possible using ligands for the dopamine transporter. Functional imaging modalities are useful in the management of patients with movement disorders, are able to monitor in an objective way the efficacy of new pharmacological therapies, can document the effect of neuronal grafting for Parkinson's disease, and delineate the progression of these diseases.