RT Journal A1 Wolkin A, Brodie JD, Barouche F, et al T1 DOpamine receptor occupancy and plasma haloperidol levels JF Archives of General Psychiatry JO Archives of General Psychiatry YR 1989 FD May 1 VO 46 IS 5 SP 482 OP 483 DO 10.1001/archpsyc.1989.01810050096021 UL http://dx.doi.org/10.1001/archpsyc.1989.01810050096021 AB To the Editor.—  The kinetics of receptor-ligand interaction predict a curvilinear relationship between free brain ckade (inset). 6 5 4 in 3 2 e d c e a m x o p p A i 0 10 20 30 40 50 60 Plasma Haloperidol Level, ng/mL 20 40 60 80 100 Plasma Haloperidol Level, ng/mL ligand concentration or neuroleptic plasma level and dopamine receptor occupancy. Based on positron emission tomography (PET) studies using 11C-raclopride in several subjects, Farde et al1 recently presented a theoretical binding curve for this relationship. Cambon et al2 derived a similar curvilinear relationship from 76Br-labeled bromospiperone PET scans of six subjects who had varying diagnoses and were receiving either haloperidol or thioproperazine.We conducted similar studies using the D2 radioligand 18F-j!V methylspiperone (NMS) to estimate dopamine receptor availability in patients with schizophrenia. Subjects included patients who were not receiving neuroleptic therapy and others who were treated