PET measurements of dopaminergic pathways in the brain.

Positron emission tomography (PET) measurements of dopaminergic pathways have revealed several new insights into the role of dopamine in the pathophysiology and pharmacology of brain diseases such as Parkinson's disease (PD), dystonia and schizophrenia. PET studies of regional blood flow or metabolism identifies sites of regional pathology. Drug-induced changes in flow or metabolism indicate the function of dopamine-mediated pathways. Measurements of radioligand binding in vivo with PET reveals abnormalities associated with specific diseases and the actions of various drugs that affect the dopaminergic system. Finally, PET measurements of the uptake of analogues of levodopa provide clues to the function of dopamine pathways potentially important for diagnosis and treatment of disease like PD.