Fig. 2. Representative standardized uptake value (SUV) [F-18]FECNT time–activity curves for the four groups studied (  table 1 ). The top two curves of each graph are the putamen (  solid symbols ), and the bottom curves are the cerebellum (  open symbols ). For each pair of similar curves, the greater one is from the second scan (  diamonds ), and the other is from the awake scan (  squares ). For the putamen curves, the  symbols and  line represent the data and model fit. The cerebellum was used as the input function for the kinetic modeling (  solid line is to guide the eye only). The  dashed line is the second putamen data (  solid diamonds ) shifted downward so that it starts at the origin and is presented to permit an initial comparison between data from the two scans. The percent change in binding potential from the model calculations between the awake and awake-control, propofol-control, lighter, and deeper scans are −9.9%, −12%, +10%, and −4.2%, respectively.