When x-raying a patient with emphysema, which adjustment to exposure settings is recommended?

• A. Increase KVP, MaS remain the same
• B. Decrease Mas, KVP remains the same
• C. Standard
• D. Decrease KVP, MaS remains the same

Answer: (B)

Emphysema produces hyperinflated lungs with a lot of air, which attenuates x-rays less than normal lung tissue. With the same kVp, that increased lucency means the image receptor can become overexposed unless the mAs is reduced. So, lowering the mAs reduces the overall exposure to the image receptor and the patient, helping to achieve proper receptor exposure and keep dose lower. Keeping the kVp unchanged preserves the characteristic chest radiograph contrast between air-filled lungs and the mediastinal structures, which is important for diagnostic quality. If you were to raise kVp, contrast would drop further, making it harder to discern details; if you raise mAs, dose goes up without a necessary gain in image quality.