What typically happens to an x-ray during coherent scatter?

During coherent scatter, an x-ray photon interacts with an atom but does not lose energy in the process. This type of interaction involves low-energy photons, which can cause the electrons in the atom to vibrate, but the overall energy of the photon remains unchanged. As a result, the photon is re-emitted at a different angle, essentially being redirected rather than scattered in a significant way that would involve a loss of energy.

This interaction contrasts with the absorption of energy, where the photon would be completely absorbed by the atom, resulting in no re-emission. In coherent scatter, because there is no energy loss and the interaction simply alters the direction of the photon, it maintains its original energy throughout the process. This helps in understanding how different types of scatter impact image quality and radiation dose during fluoroscopic procedures, since coherent scatter contributes minimally to image noise compared to other forms of scatter.