This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'Half life f-18 is: \nSelect and explain. \nA. 110 min, B. 90 min, C. 6 hours, D. 13 days', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. 110 min', 'role': 'assistant'}]