What should you expect to occur with a decrease in kVp, using digital receptors?

• A. More Compton interactions
• B. No change
• C. More photoelectric interactions
• D. Decreased dose

Answer: (C)

Lowering kVp reduces the energy of the incident photons, which makes photoelectric absorption more likely in patient tissues while Compton scattering becomes less likely. This shift means a greater proportion of interactions are photoelectric, especially in higher-Z structures like bone. Because photoelectric absorption attenuates photons more strongly and is highly energy-dependent, the resulting image shows greater subject contrast on a digital detector. In practice, maintaining the same image receptor exposure with lower kVp often requires increasing mAs, which can raise patient dose, so the idea of a decreased dose isn’t typically expected. The other options don’t fit because more Compton interactions occur with higher energies, and no change ignores the strong energy dependence of these interactions.