This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nuclear medicine, Subject name: Radiology
[{'content': 'The "R"s of radiobiology include the following except: \nSelect and explain. \nA. Repair, B. Reoxygenation, C. Repopulation, D. Reexcitation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Processes after radiation exposure are "4 R\'s" of radiobiology. Repair - Enzymatic mechanisms for healing intracellular injury. Reoxygenation- Process whereby oxygen is actually better distributed to ble cells following radiation injury and cell killing. Repopulation- Ability of the cell population to continue to divide and to replace dying and dead cells. Redistribution- Reflects the variability of a cell\'s radiosensitivity over the cell cycle.', 'role': 'assistant'}]