An interaction between x-rays and matter in which the x-ray photon ejects an inner-shell electron, causing a cascade of outer-shell electrons to fill the hole. The changing of energy shells releases secondary radiation equal to the difference in the binding energies. This absorption reaction increases the patient dose and creates contrast on the radiographic film. It usually occurs at low photon energies.
The impact of a photon emitted by an irradiated material upon interacting with a tightly bound electron (the electron in closest proximity to the atomic nucleus), resulting in the transfer of kinetic energy to the electron. This phenomenon constitutes an integral component of the photoelectric interaction characterized by genuine absorption.