Positron Emission Tomography in Parkinson’s Disease

The development of positron emission tomography (PET) and the use of radiotracers designed for the study of cerebral blood flow and metabolism have provided new insights into central nervous system function in vivo. Particularly in the case of Parkinson’s disease, different approaches have permitted a broader understanding of dopaminergic neurotransmission and the changes that take place during the progressive loss of dopaminergic neurons of the substantia nigra. In this chapter, we review physiological aspects of dopamine metabolism, as well as the patterns of alterations observed in Parkinson’s disease and related forms of parkinsonism. Studies of cerebral metabolism during performance of motor behaviors and insights derived from imaging into the complications of long term levodopa treatment (fluctuations and dyskinesias) will also be considered.