To reduce patient radiation dose, the radiographic technique chart should use which combination of kVp and mAs?

• A. High kVp and high mAs
• B. Low kVp and low mAs
• C. High kVp and low mAs
• D. Low kVp and high mAs

Answer: (C)

To reduce patient dose, you want to minimize the number of photons reaching the patient while still producing a usable image. The amount of dose is mainly influenced by the tube current–time product (mAs). By increasing the kilovoltage peak (kVp), the beam becomes more penetrating, so you can lower the mAs and still achieve adequate exposure on the image receptor. Lowering mAs directly reduces the patient’s radiation dose, which is the primary goal. The trade-off is decreased image contrast with higher kVp, but that can be managed with appropriate detector speed and imaging technique. Using high kVp with low mAs balances dose reduction with maintaining diagnostic image quality, whereas the other combinations would raise dose or fail to provide sufficient exposure.