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ICRPAEDIA: What is Radiation Dose?


Radiation dose is a measure of the amount of exposure to radiation. There are three kinds of dose in radiological protection. Absorbed dose is a measureable, physical quantity, while equivalent dose and effective dose are specifically for radiological protection purposes.

Effective dose in particular is a central feature of radiological protection. It sums up any number of different exposures into a single number that reflects, in a general way, the overall risk. The concept may be complex, but it makes radiological protection practical to implement.

Absorbed Dose

Equivalent Dose

Effective Dose

Absorbed dose is the amount of energy deposited by radiation in a mass.

The mass can be anything: water, rock, air, people, etc.

Absorbed dose is expressed in milligrays (mGy).

Equivalent dose is calculated for individual organs.

It is based on the absorbed dose to an organ, adjusted to account for the effectiveness of the type of radiation.

Equivalant dose is expressed in millisieverts (mSv) to an organ.

Effective dose is calculated for the whole body. It is sometimes called whole-body dose.

It is the addition of equivalent doses to all organs, each adjusted to account for the sensitivity of the organ to radiation.

Effective dose is expressed in millisieverts (mSv).

Read on to learn about dose limits

▶ In more detail

▶ Further Reading: Quotes from ICRP Publications