Which exposure strategy reduces patient dose by using high kVp with low mAs?

Which exposure strategy reduces patient dose by using high kVp with low mAs?

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

Answer: (B)

The key idea is exposure optimization: patient dose is driven mainly by how many photons are produced (mAs), while kVp controls how penetrating those photons are. By using a high kVp, the beam is more penetrating, so you can lower the mAs and still achieve the same receptor exposure. Fewer photons are emitted overall, which reduces the dose to the patient, even though each photon has more energy. The trade-off is reduced image contrast at higher kVp, so this approach is used when the diagnostic task can tolerate lower contrast and when maintaining adequate exposure is the priority. Other strategies that use high mAs boost the number of photons and raise dose, and using low mAs with low kVp often results in insufficient exposure or poor image quality. High mAs with high kVp also increases dose, despite the higher energy.

The key idea is exposure optimization: patient dose is driven mainly by how many photons are produced (mAs), while kVp controls how penetrating those photons are. By using a high kVp, the beam is more penetrating, so you can lower the mAs and still achieve the same receptor exposure. Fewer photons are emitted overall, which reduces the dose to the patient, even though each photon has more energy. The trade-off is reduced image contrast at higher kVp, so this approach is used when the diagnostic task can tolerate lower contrast and when maintaining adequate exposure is the priority.

Other strategies that use high mAs boost the number of photons and raise dose, and using low mAs with low kVp often results in insufficient exposure or poor image quality. High mAs with high kVp also increases dose, despite the higher energy.