Objectiva: To evaluate [11C]verapamil kinetics in humans. Methods: After intravenous injection of [11C]verapamil (370 MBq, specific activity >1600 GBq/mmol), kinetics were evaluated in five cancer patients using positron emission tomography (PET). Results: One hour after injection, accumulation of [11C] in lungs, heart and tumour was 43.0%, 1.3% and 0.9% of the injected verapamil dose, respectively. Half-lives of [11C]verapamil in these tissues were 46.2 min, 73.8 min and 23.7 min, respectively. Conclusions: Intravenously administered [11C] was mainly extracted by the lungs. Transport of a [11C]verapamil bolus out of solid tumour tissue is relatively fast.