Creation of the Radiographic Image (Chp 11)

Photoelectric effect

Total absorption of the energy of an incoming photon by an atom resulting in the emission of only a photoelectron.

Compton effect

Partial absorption of the energy of an incoming photon by an atom, resulting in a secondary x-ray and a recoil electron being emitted from the atom.

Photoelectron

An electron emitted from an atom, having absorbed all of the energy of an incoming photon.

Recoil electron

An electron emitted from an atom, having absorbed only a portion of the energy of an in- coming photon during a Compton interaction.

Backscatter

Scatter x-rays emitted at an angle greater than 90 degrees in a backward direction relative to the incident beam.

Coherent scattering

Re-emission of a photon whose energy has been temporarily captured by an orbital electron in an atom. Also known as Thompson or Classical Scattering.

Subject contrast

Difference of intensity between portions of the remnant x-ray beam, determined by the various absorption characteristics of tissues within the patient's body.