# Equivalent dose

The equivalent dose in an organ or tissue is given by:

[math] H_T = \displaystyle \sum_{R} w_RD_{R,T} [/math]

where D_{R,T} is the mean absorbed dose from radiation R in a tissue or organ T, and w_{R} is the radiation weighting factor. The SI unit of equivalent dose is joule per kilogram (J/kg^{-1}), and its special name is sievert (Sv). (ICRP Publication 123, 2013)

*ICRP Glossary entry - May 2019*

### Previous Description

The equivalent dose to a tissue or organ is deο¬ned as:

[math] H_T = \displaystyle \sum_{R} w_RD_{R,T} [/math]

where π€π is the radiation weighting factor for radiation type R, and π·π ,π is the organ absorbed dose from radiation type R in a tissue or organ ππ of the Reference Adult Male or the Reference Adult Female. As π€π is dimensionless, the SI unit for the equivalent dose is the same as for absorbed dose, J kg-1, and its special name is sievert (Sv). (From ICRP Publication 130, 2015)

The equivalent dose to a tissue or organ is deο¬ned as:

[math] H_T = \displaystyle \sum_{R} w_RD_{R,T} [/math]

where π€π is the radiation weighting factor for radiation type R, and π·π ,π is the organ absorbed dose from radiation type R in a tissue or organ ππ of the Reference Adult Male or the Reference Adult Female. As π€π is dimensionless, the SI unit for the equivalent dose is the same as for absorbed dose, joule per kilogram (J kg-1) and its special name is sievert (Sv).(From ICRP Publication 133, 2016)

**Return to Glossary**