(K-capture) An unstable atom with too many protons in the nucleus, and not enough energy to emit a positron, reaches a stable state in the way, that one proton captured an electron from the atom's inner shell (K-shell) and change to a neutron. A neutrino is emitted from the atoms nucleus by this process. The atomic mass of the atom is unchanged, but the decreased number of protons transformed the atom to a different element.

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.

(MeV) 1 Megaelectron volt = 1,000,000 eV

See Electron Volt.

The conversion electron is a low shell electron emitted for the energy change of the atom by internal conversion.

See Internal Conversion, Auger Effect, Auger Electron.

Electron excitation is the discrete energy storage in an orbital electron. The excitation energy results from the absorption of a photon (photoexcitation) or from the absorption of another electron (electrical excitation). The absorbed energy lifts the electron to a higher energy level. This process ends with electron relaxation.

See also Electron Relaxation.