Radiation Protection Glossary

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

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LD-50

In general terms, LD-50 is used as an index to describe effectiveness of some entity producing a response in a subject, where that response occurs in 50% of the subjects. In Radiation Protection it is commonly used to describe the value of Absorbed Dose in humans which would lead to Deterministic Effects and therefore radiation sickness (leading to death without medical intervention). The quantity varies depending on the literature but is likely to be between 3 and 5 Gray (Gy) (with some variance related to medical treatments).

The definition of 'safe' is not strictly an engineering term; it's a societal term. Does it mean absolutely no loss of life? Does it mean absolutely no contamination with radiation? What exactly does 'safe' mean?

– Henry Petroski