Radiation Protection Glossary

A radiation protection glossary for Radiation Protection Supervisors (RPS), Radiation Protection Advisers (RPA) and anyone else interesting in radiation safety terms and definitions. The glossary is a mixture of health physics , phrases related to radiation protection legislation, transport, practical safety, technical terms and similar.

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Annihilation (Positron - Electron)

Published: Oct 12, 2018

Annihilation (Positron - Electron) radiation occurs when an electron (negatively charged) collides with a Positron (positively changed & the electron 'anti-particle'). The usual result is the emission of two gamma ray photons , each of 511 KeV and 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).

Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less

– Marie Curie -