What effect does increasing KeV have on the chance of Compton scattering?

Increasing the energy of the incident photons, measured in kiloelectronvolts (KeV), influences the likelihood of Compton scattering. Compton scattering occurs when photons collide with loosely bound outer shell electrons of atoms in tissue, resulting in the transfer of energy and change of direction of the photons.

As the energy of the photons increases, the probability of Compton scattering actually decreases, primarily because higher energy photons are more likely to pass through matter without interacting. At higher energies, the likelihood of photon interaction is dominated by other processes, such as pair production and photoelectric effect, depending on the material and the energy range. In fact, the Compton effect is most significantly relevant at mid-range energies, typically around 20 to 150 keV.

Thus, the relationship is such that as the energy increases beyond a certain point, the chances of Compton scattering do not increase; they actually decrease. The correct understanding of this energy interaction is crucial for interpreting the results in fluoroscopy and understanding radiation physics.