Figure 4.

[¹¹C]Diphenhydramine PET kinetics in rats. (a) Mean time–activity curve (TAC, SUV value versus time; n = 4) for the rat brain after injection of [¹¹C]diphenhydramine. (b) Representative TACs obtained from different brain regions (pons, medulla, striatum, hippocampus, thalamus, midbrain, cortex, and cerebellum) during displacement experiments: rats were injected with unlabeled diphenhydramine 1 mg kg⁻¹ i.v., 30 min after [¹¹C]diphenhydramine injection. (c) Percentage of parent (unmetabolized) [¹¹C]diphenhydramine in plasma versus time. (d) Mean TAC of unmetabolized [¹¹C]diphenhydramine (metabolite-corrected input function) in plasma.