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': 'Which of the following agents is used to measure glomerular filtration rate (GFR) – \nSelect and explain. \nA. Iodohippurate, B. Tc99m – DTPA, C. Tc99m – MAG3, D. Tc99m – DMSA', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In dynamic renal scintigraphy :-\n\n\nGFR\xa0 → Tc - 99m - DTPA\nEffective renal plasma flow → Tc-99m - MAG3, I\xa0- 123 - OIH.', 'role': 'assistant'}]