What happens when the kVp is decreased?

When the kilovolt peak (kVp) is decreased, the overall energy of the x-ray beam is reduced. This change primarily affects the contrast of the radiographic image. Lowering the kVp results in a greater difference in attenuation between different tissues, which enhances the contrast. Higher contrast is beneficial in visualizing structures where differences in density are critical, such as distinguishing between soft and hard tissues.

This is due to the fact that lower energy x-rays are more readily absorbed by tissues, which can lead to a sharper transition between areas of varying density on the image. Therefore, as kVp decreases, the contrast of the radiographic image increases, making it easier to differentiate between anatomical features.

While other aspects of radiography may also be affected when the kVp is altered, the most significant impact when decreasing kVp is the increase in contrast within the image.