Mean time-activity curves (standardized uptake value, SUV ±standard deviation, SD) of unmetabolized (R)-[11C]verapamil in arterial plasma from 3.5 to 40 min after radiotracer injection for baseline scans (i.e. without tariquidar administration, n=5) and scans after administration of 2 mg/kg tariquidar (n=5) and from 3.5 to 60 min after radiotracer injection for scans after administration of 3, 4, 6 and 8 mg/kg tariquidar (n=3 per dose group).