This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Radiology
Scan used to estimate collecting system dilatation is 
Select and explain. 
A. 99m Tc- DTPA scan, B. MAG 3 scan, C. DMSA scan, D. Hippuran scan
A: 99m Tc- DTPA scan
Answer: A: 99m Tc- DTPA scan 
Explanation: (Ref: Grainger&;s diagnostic radiology, 6th ed; page 134)