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What is absorbed dose?

Absorbed dose is a physical quantity to measure the radiation energy absorbed by unit mass of substances. Under normal circumstances, the larger the absorbed dose, the larger will be the hazard.

The unit of absorbed dose is Gray, whose symbol is Gy.

Absorbed dose applies to all types of ionizing radiation and substances. For different types of radiation under different exposure conditions, however, the same absorbed dose can cause different biological effects on human bodies.

"Equivalent Dose" and "Effective Dose" are used for assessment of the risk of biological effects produced by ionizing radiation. The unit is Sievert, whose symbol is Sv.

Press here for more information on absorbed dose, equivalent dose and effective dose.


Doses absorbed under different conditions

Doses absorbed under different conditions
(Source:"Living with Radiation" published by the National Radiological Protection Board, UK (1998))


The above information is provided by RHD of DH
Department of Health

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Last revision date: <01 Oct 2019>