TSPO and schizophrenia: However, after applying a new kinetic model that accounts for putative binding to vasculature,22 and then normalizing regional binding to that of whole brain, a significant increase in [11C]PBR28 signal in schizophrenia and in the at-risk state was found in some gray matter regions.21 Each of these three studies included at most one or two patients in their first years of schizophrenia and therefore these studies were unable to evaluate whether TSPO in the brain was increased with hypothesized inflammatory processes in the early stages of disease.