Contrast in a digital image is primarily controlled by which parameter?

Contrast in a digital image is primarily influenced by the kilovolt peak (kVp) setting. The kVp determines the penetration power of the X-rays produced during imaging; higher kVp values yield more penetrating X-rays. This increased penetration results in a broader range of photon energies, effectively enhancing the difference between various tissue densities in the image. Consequently, when the kVp is adjusted, the resulting differences in gray scale within the image are directly correlated with changes in the contrast observed—the greater the difference in the X-ray absorption of different tissues, the higher the contrast in the digital image.

While factors like milliampere-seconds (mA), size of the sensor, and exposure time do affect image quality, they do not directly control contrast as significantly as kVp. The mA primarily relates to the quantity of radiation produced, which affects image density rather than contrast itself. The size of the sensor is more about spatial resolution and image detail, and exposure time is related to the amount of radiation the sensor receives rather than the contrast between different structures in a digital image.