等效剂量（Equivalent dose）为吸收剂量（D）乘上品质因子（QF）的值，符号为DE，定义为DE=D×QF，单位为西弗（sievert，缩写为Sv）。

由于不同电离辐射在相同的吸收剂量下会对生物组织造成不同的影响，故需要使用等效剂量。

Equivalent dose is a dose quantity used in the International Commission on Radiological Protection (ICRP) system of radiological protection.

It represents the stochastic health effects (probability of cancer induction and genetic damage), of low levels of ionizing radiation on the human body. It is derived from the physical quantity absorbed dose, but also takes into account the biological effectiveness of the radiation, which is dependent on the radiation type and energy.