What happens when the kilovoltage applied to the x-ray tube is increased?

When the kilovoltage (kVp) applied to the x-ray tube is increased, several effects occur in the x-ray beam, particularly in terms of the energy and quality of the photons produced. One of the primary outcomes of increasing the kilovoltage is that the percentage of high-energy photons produced in the beam increases.

Higher kilovolt settings increase the acceleration of electrons from the cathode to the anode in the x-ray tube. As these electrons collide with the target material (typically tungsten), they generate x-rays. The resultant beam contains not only a greater quantity of photons but also a wider range of photon energies. This means that there is a significant increase in the number of high-energy photons within that beam, which enhances the penetrability of the x-rays.

The presence of more high-energy photons allows for improved image quality because these photons can more effectively traverse various tissues, ultimately leading to better contrast in the resulting images. In clinical settings, this is why radiologists often adjust the kilovoltage depending on the specific requirements of the examination being performed.

Therefore, the increase in high-energy photons is a crucial factor in optimizing image acquisition and enhancing the diagnostic quality of radiographic images.