Imaging the neurochemical brain in health and disease.

Neurochemical transmission is a fundamental element of brain organisation that has been relatively unexplored in the living human brain. Continuing advances in radionuclide imaging, particularly positron emission tomography (PET) and single photon emission tomography (SPET), mean that elements of neurochemical transmission can now be directly measured in vivo. With these techniques convincing abnormalities of monoaminergic neurotransmitter systems have been revealed in illnesses such as Parkinson's disease and schizophrenia. Furthermore, mechanisms of drug action and treatment responses can be monitored in vivo. This brief review describes some of our recent attempts to image the neurochemical brain in health and disease at the MRC Cyclotron Unit, Hammersmith Hospital, London.