DRD2 and psychotic disorder: In a series of positron emission tomography (PET) studies using the high-affinity D2-R radioligands [11C]FLB 457 and [18F]Fallypride, which were developed for low-density extrastriatal regions [7, 8], D2-R binding has shown to be lower in thalamus in patients with psychosis compared with controls [9–12].