In vivo imaging of neurotransmitter systems in neuropsychiatry

A wide variety of nuclear medical, radiological, ultrasound, electroencephalographic, and other neuroimaging techniques are available to assist clinicians in the characterization and treatment of neurological and psychiatric disorders by the visualization of the living human brain. In particular, radioligand neuroreceptor imaging can be accomplished by positron emission tomography (PET) and single photon emission computerized tomography (SPECT), nuclear medical procedures involving the administration of radioisotopes to the subject. While currently primarily a research tool, several practical clinical applications of radioligand neuroreceptor imaging are available today. Radioligand neuroreceptor imaging permits the determination of optimal dosages of traditional and novel psychoactive agents to produce maximal beneficial effects but minimal adverse effects. Furthermore, radioligand neuroreceptor imaging allows the identification of dysfunction in the release and transport of neurochemicals, such as second messenger systems, in the brains of individuals afflicted with different biological subtypes of nervous and mental diseases to facilitate the application of effective interventions to correct the underlying abnormalities. Gene therapy is another application of imaging techniques that provides the means to correct abnormalities in victims of malignancies, such as brain cancers, and other diseases. Thus, the diagnosis and treatment of nervous and mental disorders is enhanced by the utilization of in vivo imaging of neurotransmitter systems.