The tissue weighting factor is the proportion of the tissue-specific risk to the whole-body risk.
If the specific tissue dose is multiplied by the appropriate tissue weighting factor to obtain the equivalent whole-body dose, then dividing the equivalent whole-body dose by the tissue weighting factor should yield the specific tissue dose.
Although assigning specific values to tissue weighting factors facilitates calculations, it is overly simplistic and fails to account for the influence of known risk determinants.
Further, application of tissue weighting factors is problematic because of the large uncertainties in the values.
Incorporating weighting factors into dose limits eliminates uncertainties inherent in using tissue weighting factors in the risk-based system.
Since radiation and tissue weighting factors are dimensionless, there is no need to use other quantities to describe what is simply a weighted absorbed dose.