How does increasing kilovoltage peak (kVp) affect image contrast?

How does increasing kilovoltage peak (kVp) affect image contrast?

• A. It reduces penetrating power and increases contrast
• B. It has no effect on contrast
• C. It increases penetrating power and reduces image contrast
• D. It increases contrast and raises patient dose

Answer: (C)

Increasing kilovoltage peak raises the energy of the x-ray photons, so the beam becomes more penetrating. With higher energy, tissues attenuate x-rays less differently, which reduces the variation in attenuation on the image and yields a longer gray-scale with lower contrast. Higher kVp also tends to produce more scatter, further diminishing contrast. While exposure settings can be adjusted to maintain receptor exposure, the consistent imaging effect of raising kVp is greater penetration and lower image contrast.

Increasing kilovoltage peak raises the energy of the x-ray photons, so the beam becomes more penetrating. With higher energy, tissues attenuate x-rays less differently, which reduces the variation in attenuation on the image and yields a longer gray-scale with lower contrast. Higher kVp also tends to produce more scatter, further diminishing contrast. While exposure settings can be adjusted to maintain receptor exposure, the consistent imaging effect of raising kVp is greater penetration and lower image contrast.