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': 'All isotopes are used for thyroid except: \nSelect and explain. \nA. 1-131, B. 1-123, C. 1-122, D. All', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. 1-122', 'role': 'assistant'}]