How does increasing kVp affect the mAs required to achieve the same receptor exposure?

• A. It allows a lower mAs to achieve the same receptor exposure.
• B. It requires higher mAs to achieve the same receptor exposure.
• C. It has no effect on mAs.
• D. It eliminates the need for mAs.

Answer: (B)

Raising kVp makes photons more penetrating, so for the same amount of exposure at the image receptor you can reduce the tube current–time product (mAs). In practice, increasing kVp by about 15% is commonly paired with roughly halving the mAs to keep receptor exposure the same. This is why higher kVp allows a lower mAs to achieve the same receptor exposure. Keep in mind that while this preserves exposure, it also lowers image contrast and can affect noise, so settings must balance dose, contrast, and image quality.