# Equivalent dose

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

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

where [math]D_{R,T}[/math] is the mean absorbed dose from radiation [math]R[/math] in a tissue or organ [math]T[/math], and [math]w_R[/math] 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)

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See also the ICRPaedia entry on absorbed, equivalent, and effective dose.

## Previous glossary entries

### from ICRP Publication 130, 2015

The equivalent dose to a tissue or organ is deﬁned as:

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

where [math]w_R[/math] is the radiation weighting factor for radiation type [math]R[/math], and [math]D_{R,T}[/math] is the organ absorbed dose from radiation type [math]R[/math] in a tissue or organ [math]r_T[/math] of the Reference Adult Male or the Reference Adult Female. As [math]w_R[/math] 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 133, 2016

The equivalent dose to a tissue or organ is deﬁned as:

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

where [math]w_R[/math] is the radiation weighting factor for radiation type [math]R[/math], and [math]D_{R,T}[/math] is the organ absorbed dose from radiation type [math]R[/math] in a tissue or organ [math]r_T[/math] of the Reference Adult Male or the Reference Adult Female. As [math]w_R[/math] 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).