Radiation Protection Glossary
Search the Glossary by either clicking on a letter or typing a Keyword into the search box.
Annihilation (
Positron -
Electron) radiation occurs when an electron (negatively charged) collides with a Positron (positively changed & the electron’s anti-particle). The usual result is the emission of two
gamma ray photons – each of 511 KeV travelling away from each other. The example in this glossary shows the decay of F-18 by positron emission followed by the resulting annihilation radiation. This process has application in Positron Emission Tomography (PET imaging).
