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.

Search the Glossary by either clicking on a letter or typing a keyword into the search box. This glossary is relational so when looking at one term you can click through to other related terms as required.

For formal advice, see our Radiation Protection Adviser pages. 


    Medical Exposure

    Medical exposures relate to planned and deliberate exposure of a patient to Ionising Radiation for medical diagnosis or treatment. E.g. the use of X-Rays by dentists, CT Scans and incorporation of Sealed or Unsealed sources in the body. There are no 'Dose Limits' but there are usually recommended upper levels (e.g. diagnostic reference levels). The ICRP states that only necessary exposures should be made and these should be justified on the basis that the '..medical benefits of the exposure outweigh the radiation risk..' - i.e. a minimum dose that would be consistent with the medical benefit. The technology being medical exposures is advancing all the time. The use of collimated beams from advanced linear accelerators and proton beam irradiation is providing ever better cancer treatment.


    General term for materials used in nuclear reactors to reduce the energy (speed) of Fast Neutrons to that of Thermal (slow) Neutrons. The thermal neutrons are then able to interact and Fission with U-235.

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 -