# Effective dose equivalent

The tissue weighted sum of dose equivalent to an organ or tissue from all specified organs and tissues of the body, given by the expression

$H_E = \displaystyle \sum_{T} w_tH_t$

where HT is the dose equivalent to an organ or tissue T and wT is the tissue weighting factor. The SI unit of effective dose equivalent is joule per kilogramme (J kg-1), and its special name is sievert (Sv). A quantity introduced by ICRP in Publication 26 (ICRP, 1977) and replaced by effective dose in ICRP Publication 60 (ICRP, 1991).

ICRP Glossary entry - May 2019