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
Radiation exposure is the least in the following procedure – 
Select and explain. 
A. Micturating cystourethrogram, B. IVP, C. Bilateral nephrostomogram, D. Spiral CT for stones
A: Micturating cystourethrogram
Answer: A: Micturating cystourethrogram 
Explanation: Amongst the given options micturating cystourethrogram has least radiation exposure with number of chest x-ray equivalent of 60.
IVP has chest x-ray equivalent 120, nephrostomogram has x-ray eqiuvalent 170, and CT Plevis has x-ray equivalent 500.