Effective biomarkers have been needed for diagnostic purpose and evaluation of the effects of drugs.Positron emission tomography(PET)enables us to viualize several components of brain activites including glucise metabolism of brain activity and neurotransmitter receptors and transporters.In vivo neuroimaging including neuroreceptor imaging and enzyme activity imaging have contributed to drug evaluation by1)ratinal drug dosing,2)biodistribution of drug,3)therapeutic rationale for drug utilization,and4)mechanism of drug action[1].In this article,we focused on rational drug dosing using receptor occupancy and proof-of-concept of drugs,as well as new therapeutic methods using PET
