Low-kVp technique is most associated with which type of contrast scale?

• A. High-contrast
• B. Low-contrast
• C. Long-scale contrast
• D. Short-scale contrast

Answer: (A)

Low-kVp imaging enhances image contrast because at lower energies the photoelectric interaction dominates, and this interaction is highly dependent on tissue density and atomic number. This makes attenuation differences between structures like bone and soft tissue much more pronounced, so more photons are absorbed in some areas and more pass through others, resulting in a stark black-and-white image. That’s high-contrast (short-scale) imaging. In contrast, higher kVp reduces subject contrast by increasing scatter and making tissue attenuations more similar, which produces many gray tones (long-scale, low-contrast).