2) BASIS FOR DOSIMETRIC QUANTITIES USED IN RADIOLOGICAL PROTECTION 2.1 General The subject of the report is very important and clarification in the jungle of dose quantities and units is very important. However, some doubts arise that clarification will not take place, mainly for structural shortcomings as occasionally traditional in ICRP. This seems necessary because paragraph are often very lengthy and do not distinguish between new issues, old obsolete terms, general aspects and details. This makes the reading difficult and it can be expected that readers resign before discovering important issues, which are without any doubts in the report. The glossary is highly appreciated. As uncertainty is addressed in this report, and some practical issues are also raised, the question how to prove compliance of as assessed (measured, calculated) number with an inherent often large uncertainty with a predefined limit (a quantity different in nature, by definition without an uncertainty) is not mentioned. As some approaches are discussed, some lines on this issue might be useful. See comments to ICRP “representative individual” 2.2 Restructuring The restructuring should lead to an easily readable main text (a “User” friendly part or an extended summary) including the key issues with reference to explanatory material, historical development etc. The very important second part can be developed in length and has to provide the scientific and conceptual background as well as the historical development. 2.3 Comments and suggestions: Inconsistency: p.3: this report uses the term “Health effects”, the report discussed above “health risks” p.4. new terms as Tissue reactions, radiation weighted dose appreciated p.7 last para of 2., 2nd line from top …Sv must… p.15 equ (3.6) a hint for what purpose this equation is to be used will be helpful p.21: 4.1 Radiation weighting factors It has to be mentioned (and a reference included) that the term applies in the future also for nonhuman species (see comments 3 on reference animals below), but with substantially different definition Although it is mentioned in some paragraphs, there is still some confusion. Restructuring following 2.2 and a table should be included containing information as this might be helpful term Exclusively to be used for RBE Tissue reaction in humans Q ICRU wT Stochastic effects in humans Effective dose Stochastic effects in humans p.22: para 4.1.1 seems unnecessary at all and therefore misleading , as there is not relation to other chapters. In addition, the term “radiation quality” is coined already in standardisation to describe given exposure conditions (potential, filtration, etc) rather than the presentation of a spectrum. 4.1.2 to 4.1.6: Restructuring following 2.2 p.31 a table with old and new numbers might be illustrative p.33 “Practical application…” of what? The chapter seem inhomogeneous, as “radioactivity “ is not really an application as well as collective dose. 5.4 and 5.8 are important extensions of the concepts shown above, and 5.2, 5.3, 5.5., 5.6, 5.7 are applications of the concepts for defined exposure condition. The definition of activity is a little lost in this chapter. p.34: activity concentration and specific activity are defined very academical and in an uncommon way and departing from other definitions coined by ICRP (see e.g. ICRP draft on reference animals). More common seems to apply activity concentration in cases where a bulk material is contaminated, as air, water, soil, etc, and specific activity in cases where it is intended that activity in a material (e.g. a solution to be administered) p.34 explanation of equ 5.2 seems too simple and academic. Biological retention in the body does not apply as this is dependent on the metabolism and the affected organs. Biological retention in the considered organ is a little better, but a reference to an ICRP report should be made. p.34 below equ 5.3: “recommended” should be expressed stronger as it is a conceptional issue p.36 paras on ALI and DAC should moved to an annex. p.37 5.2.2 is lost here and should be deleted p.40 equ (5.9): see comment to equ 3.6 5.5 as it can assumed that the data sets to 5.6 and 5.7 refers to such a person, this should be mentioned as well with references to recommended data sets to be applied. 5.8 It happened by chance that I proposed recently (being unaware of this report) something similar on the limitiation of the application of the concept of Collective dose and integration into the future in a paper for a conference this year. This can be submitted to you if required. p.44 6. Uncertainties It should be mentioned that variability and uncertainty are to be distinguished. I enclose a few sentences already enclosed previously in a statement to another ICRP draft. ( see comments to Dose of the representative individual”