Editing Sievert (section)

==Internal dose quantities==
{{Main|Committed dose}}
The sievert is used for human internal dose quantities in calculating [[committed dose]]. This is dose from radionuclides which have been ingested or inhaled into the human body, and thereby "committed" to irradiate the body for a period of time. The concepts of calculating protection quantities as described for external radiation applies, but as the source of radiation is within the tissue of the body, the calculation of absorbed organ dose uses different coefficients and irradiation mechanisms.

The ICRP defines Committed effective dose, <math>E(t)</math> as the sum of the products of the committed organ or tissue equivalent doses and the appropriate tissue weighting factors <math>W_t</math>, where <math>t</math> is the integration time in years following the intake. The commitment period is taken to be 50 years for adults, and to age 70 years for children.<ref name="ICRP publication 103 - Glossary"/>

The ICRP further states "For internal exposure, committed effective doses are generally determined from an assessment of the intakes of radionuclides from bioassay measurements or other quantities (e.g., activity retained in the body or in daily excreta). The radiation dose is determined from the intake using recommended dose coefficients".<ref>ICRP publication 103 - Paragraph 144.</ref>

A committed dose from an internal source is intended to carry the same effective risk as the same amount of equivalent dose applied uniformly to the whole body from an external source, or the same amount of effective dose applied to part of the body.