Change in thalamic binding with varying masses of unlabeled nifene. Thalamus/Cerebellum ratio curves are shown, which include a second high mass [18F]nifene injection at 60 min. Each different symbol represents a different subject. Specific activities of the second injection are denoted in the legend, upper left. A nonlinear Scatchard plot is shown inset, upper right illustrating the calculation of an approximate KDapp value.