What happens when the kV setting is increased on an X-ray machine?

Increasing the kV (kilovolt) setting on an X-ray machine primarily increases the penetrating power of the X-rays produced. The kV setting controls the voltage of the electrons accelerated across the X-ray tube. A higher kV results in higher energy X-rays, which can penetrate dense materials more effectively, including various types of tissues in the body. This enhanced penetrating power is crucial for obtaining diagnostic images of thicker or denser anatomies without requiring excessive exposure times or increasing the dose of radiation to the patient.

While it may seem that increasing kV could affect other aspects of X-ray imaging, such as exposure time or image contrast, the most significant and direct effect is indeed on the penetrating power of the radiation. With more energy in each photon, the X-rays can pass through body tissues and reach the detector more effectively, reducing the likelihood of needing longer exposure times to achieve an adequate image.