The document is written so that some aspects are explained in a fairly basic way and then this changes to a higher technical level. It may be useful to decide clearly on the target audience and ensure the document is written for this audience. A summary detailing changes and how they have arisen would be usfeul and make the document more 'useable'. Section 4.1.6, 3rd paragraph, states for heavy ions "...a more realistic approach may be chosen based on the calculation of a mean quality factor in the human body as mentioned in section 4.1.3 In operational circumstances health physicists should make their own judgements on values of WR when sufficient relevant data are available." This statement is very open ended and not that helpful to most operational health physicists. Guidance on how this information could be obtained and how it can be judged as to whether it is appropriate wold be helpful. There are a couple of typos on ICRP dates, Section 5.1"ICRP publication 38 (1983) has been used in ICRP publictaions since 1980" and Section 5.5 "Publication 89 (ICRP 2003)" and "Publication 89 (ICRP 2002)"