When an electron collides with its antiparticle, a positron, causing both elements to be completely destroyed and in most cases resulting in the emission of gamma rays.

See also Electron, Positron and Antiparticle.

Electron relaxation is the release of a short time stored discrete energy by an orbital electron which will then falls back to a lower energy level. The energy difference is emitted by the electron as a photon or given to another particle.

See also Electron Excitation.

(eV) Electron volt is an energy unit defined as 1.60919 x10^-19 joules (in older unit 1.60919 x10^-12 erg). One electron volt is equal to the kinetic energy required to raise an electron through a potential difference of one volt (in a vacuum). The electron volt is not an SI unit but its use is valid within the International System for atomic (eV), electronic (keV), nuclear (MeV), and subnuclear processes (GeV or TeV).

In medical imaging used units:
MeV: One million electron volts
keV: One thousand electron volts.

(EDP) The term electronic data processing describes the automated processing of commercial data by computer systems.

See also Boot Terminal, Anticoincidence, Electronic Noise, Impedance Matching, Demodulator, and Hard Disk.

Electronic noise decreases the image quality. There are various noise sources in any electronic system, including Johnson noise, shot noise, or thermal noise. Electronic noise can be caused by vibrations of any of the hardware components, especially the rotational components of a CT scanner or power fluctuations.