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: Tc99m-Diethylene Triamine Pentothenic Acid (DTPA) is an agent of choice widely used in measuring GFR. Ref: Renal Disease: Techniques and Protocols By Michael S Goligorsky, Page 87; Paediatric Uroradiology By Richard Fotter, ALbe L Bae, Page 47', 'role': 'assistant'}]