PET represents the most powerful tool available for the measurement of in-vivo brain function. The basic principles of the technique and its application to the study of brain energy metabolism and neuroreceptor function are described by reference to findings from clinical studies of cerebral metabolism in neurological and psychiatric disorders. The extension of such resting state investigations by the application of activation paradigms in dynamic studies is discussed. The potential of PET as a tool to investigate neuroreceptor function is outlined in the context of preliminary findings from studies of dopaminergic function in schizophrenic patients.
