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': 'Renal GFR is best measured by – \nSelect and explain. \nA. Tc 99 DMSA, B. Tc 99 Pyrophosphate scan, C. Tc 99 DTPA, D. Creatinine clearance', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Inulin clearance\xa0is the gold standard for assessing GFR. It is the preferred measure of GFR when an accurate measure is critical. However, this method is not performed in clinical practice, because of technical complexity and limited availability.\nNext to inulin,\xa0radiocontrast agents (Tc - DTPA)\xa0are most accurate.\nHowever, because of its convenience and low cost, creatinine clearance is most commonly used.', 'role': 'assistant'}]