[Clinical positron emission tomography: brain imaging]

PET produces images of physiological functions at molecular level which can be used to measure different vital processes, including blood flow and perfusion, glucose metabolism, oxygen utilization and receptor-ligand binding rates. Unlike anatomical imaging modalities, such as CT and MR, PET allows for the assessment of biochemical and physiological changes related to any function. Recently, the clinical indications for PET have increased dramatically. PET can reduce the overall cost of medical care, because it increases the certainty of diagnosis and clinical stage of disease, and therefore eliminates the expense of unnecessary testing or treatment.