Effective Dose (E)

The summation of the products of the equivalent dose received by specified tissues or organs of the body (HT) and the appropriate tissue weighting factor (wT)--that is, E = ΣwTHT. It includes the dose from radiation sources internal and/or external to the body. For purposes of compliance with this Order, equivalent dose to the whole body may be used as effective dose for external exposures. The effective dose is expressed in units of rems (or sieverts).