In radiography, which setting is most closely associated with image contrast?

In radiography, which setting is most closely associated with image contrast?

• A. Film type.
• B. mA.
• C. KVP setting.
• D. Exposure time.

Answer: (C)

Contrast in radiographic images is governed mainly by beam quality, which is set by the kilovoltage peak. The kilovoltage determines the energy of the x-ray photons; higher energy makes the beam more penetrating and reduces the differences in attenuation between tissues, resulting in lower subject contrast and a greyer image. Lower kilovoltage increases the differences in attenuation, producing greater contrast with more distinct black-and-white areas. The other factors mainly affect how many photons reach the detector (density) rather than the range of gray tones: increasing mA or exposure time changes brightness; film/screen choices influence inherent contrast but the setting most closely tied to adjusting contrast is the kilovoltage peak.

Contrast in radiographic images is governed mainly by beam quality, which is set by the kilovoltage peak. The kilovoltage determines the energy of the x-ray photons; higher energy makes the beam more penetrating and reduces the differences in attenuation between tissues, resulting in lower subject contrast and a greyer image. Lower kilovoltage increases the differences in attenuation, producing greater contrast with more distinct black-and-white areas. The other factors mainly affect how many photons reach the detector (density) rather than the range of gray tones: increasing mA or exposure time changes brightness; film/screen choices influence inherent contrast but the setting most closely tied to adjusting contrast is the kilovoltage peak.