sum of each contribution of the absorbed dose by a tissue or an organ exposed to several radiation types, weighted by the each radiation weighting factor for the radiations impinging on the body
NOTE 1 The organ equivalent dose, an ICRP-60  defined quantity, is normally represented by HT, and usually shortened to equivalent dose. In accordance with the definition, it is calculated with the equation below (for further discussion, see ECSS-E-HB-10-12 Section 10.2.2):
NOTE 2 The organ equivalent dose is measured in units of sievert, Sv, where 1 Sv = 1 J/kg. The unit rem (roentgen equivalent man) is still used, where 1 Sv = 100 rem.