This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: X-RAYS, Subject name: Radiology
To improve contrast of an X-ray film in a morbidly obese patient, what should be done? 
Select and explain. 
A. Increase KVP, B. Increase MAS, C. Decrease KVP, D. Decrease MAS
B: Increase MAS
Answer: B: Increase MAS 
Explanation: Contrast depends on Kvp, Current and exposure time. Contrast can be improved mainly by decreasing kVp. To improve contrast either decrease kVp or increase mAs. In morbidly obese patients, Kvp cannot be decreased as it determines the penetration, so Increasing mAs is a better answer here.