Dopamine is a neurotransmitter responsible for the control of movements. The cells that produce dopamine are located in an area of the brainstem, the substantia nigra<\/em>. Through nigro-striatal projections, dopamine is then secreted from the axonal terminals into the striatum, the area of the brain that plays an important function in regulating motor activity. In Parkinson\u2019s disease, dopamine cells degenerate and their loss is responsible for the motor symptoms that characterise the disorder, such as bradykinesia, rigidity and tremor.<\/p>\n Using a brain imaging technique known as Positron Emission Tomography (PET), we have measured the availability of the dopamine transporter protein (DAT) that regulates the dopamine levels in the brain. Since 2008 the high-resolution research tomograph (HRRT) has been operational at the PET-Centre of the Department of Clinical Neuroscience at Karolinska Institutet. The HRRT is the PET systems with highest resolution (~2mm) for imaging of the brain. High-resolution PET combined with the best-in-class DAT imaging agent, [18<\/sup>F]FE-PE2I, enables the imaging of the DAT in the dopamine cell bodies, on the axons and on the nerve terminals (Fig. 1). DAT imaging with high-resolution PET can be used as a biomarker to map the entire dopamine system in vivo<\/em>.<\/p>\nHow DAT imaging with high-resolution PET can be used as a mapping tool<\/h3>\n