What effect does increasing kilovoltage have on radiographic contrast?

Increasing kilovoltage (kV) in radiographic imaging primarily affects the energy of the X-ray beam. As kV increases, the energy of the X-rays also increases, resulting in a greater penetration power through the tissues being imaged. This higher energy allows more X-rays to reach the receptor, which can lead to a more homogeneous exposure of tissues.

As a consequence, with the increased kV, tissues with varying densities become less differentiated in terms of the radiation absorbed, which in turn leads to a decrease in contrast on the radiograph. Contrast is defined as the difference in optical density between adjacent areas on the film. Therefore, with higher kilovoltage, the difference in density diminishes, resulting in lower radiographic contrast.

In summary, increasing kilovoltage reduces the differences in exposure received by various tissue types, leading to overall reduced contrast in the resulting image.