Abstract: Positron emission tomography (PET) with positfon-emitting tracers can provide the biochemical information which is obtained from the measurement of cerebral blood volume (rCBV),regional cerebral blood flow (rCBF) and/or integrality of the blood-brain barrier, regional cerebral glucose utilize rate, oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (rCMRO 2), and of amino acids (rCMRaa), and the site, density and distribution of the receptors. Thus,PET imaging can investigate the physiochemical process and characteristic of brain diseases and consequently insights concerning the evaluation of disease states, response to therapy, and prognostic indicators.