ICRP 26/30 Philosophy( dose equivalent (rem or Sv) and effective dose equivalent,Stochastic and Nonstochastic effect.)
Because different radiations cause different biological effect, so we define:
dose equivalent is equal to dose by quality factor.
Because different tissues respond differently to radiations, so we define:
effective dose equivalent is equal to dose equivalent by tissue weighting factor W(tissue). It only applies to stochastic case.
For nonstochastic case, we consider a 50 year organ dose.
For stochastic case, we consider doses upon whole body.
we also have limitation on intake dose( also stochastic and non-stochastic).