This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
[{'content': "I131 is the preferred treatment for: \nSelect and explain. \nA. Children, B. Young adults with recent onset Graves' disease, C. Elderly patients with ischemic hea disease, D. Pregnant women", 'role': 'user'}, {'content': 'Answer: C \nExplanation: (Ref: KDT 6/e p253) I131 is contra-indicated in children and young adults because if hypothyroidism develops in response to radioactive iodine, it is permanent. Use of radioactive iodine is contra-indicated in pregnancy. In ischemic hea disease patients, surgery should be avoided. I131 therapy is a good alternative in such patients.', 'role': 'assistant'}]