Why it is advisable to keep wR = 1 and Q = 1 for photons and electrons

It has been well known for a long time that the biological effectiveness of photons and electrons depends on the mean linear energy transfer (LET) of the radiation considered, e.g. (60)Co gamma rays are less effective than soft or hard X rays. Nevertheless, the protection and operational dose quantities applied in radiological protection include weighting factors, w(R) or Q, respectively, which were set to 1 for all low-LET radiations. Lack of precise information, simplicity and general practical considerations are the main arguments for this convention. However, a more detailed discussion on the practical aspects supporting this procedure is missing. The paper discusses in more detail some of these aspects regarding internal and external exposure situations, which may support the idea of continuing to use w(R) = 1 for photons and electrons and, correspondingly, using Q(L) = 1 for L < 10 keV microm(-1).