General Comments: 1. Overall comment. There is a good document hidden inside the draft, but a strong editorial/technical hand is needed in all sections, including the main points and the conclusions, to: Reduce the considerable amount of repetition; Improve the focus of the document; Improve and simplify the English – many sentences have complex constructions, odd word choice and some degree of tautology. Individual sections need to be brought to the same English style to remove the diversity between sections written by different authors. 2. The terms – quality assurance programme, quality assurance procedures, QA, QC, quality control procedures, and other combinations – are used in inconsistent ways in different parts of the document – possibly reflecting different authors. Having an appropriate, “intelligent”, quality assurance programme is one of the take home messages of the report, so it is important that the various terms associated with the programme are used consistently and correctly throughout the document. Up-to-date terminology refers to ‘quality management’ rather than ‘quality assurance’. 3. The role of quality audit is de-emphasized in the document, although it is an important tool in accident/incident prevention; this includes dosimetry audits of the various levels, TPS audits, and an internal and external clinical or comprehensive audits. The IAEA work in this area deserves to be mentioned, both for the dosimetry audit and clinical audit. 4. Chapter 3 has a different structure compared to the reminder of the document. The summaries in bold at the beginning of each subsection may be omitted without a loss of information. In places, Chapter 3 raises a speculative tone, especially describing potential inattentions by RTTs, rather that providing the proper evidence, for example from ROSIS. 5. Chapter 5; This chapter is quite uneven in its discussion of prospective approaches, and is difficult to read. Perhaps a few illustrative diagrams would help. It seems premature for some of the information in this chapter to be published by ICRP, especially the specific numerical results of the PSA analysis. These results depend on the completeness of description of the chain of events in a specific radiotherapy procedure and the accurate assessment of the probability of occurrence of certain failures. This is however, to a large extent, a subjective decision by the analysts. Therefore the numbers/percentages presented as the PSA results in Chapter 5 cannot be accurate and it is suggested to remove them from the report. There is an on-going work in this area by AAPM and other groups, and once the results are available, the review of prospective approaches will become more complete. 6. Uniform terminology should be used throughout the document, for example Sec. 1 ‘gated therapy’, Sec. 3 ‘breathing management in therapy’; Para 1) IMAT, Para 3) VMAT; R&V is used in places instead of RTIS. It is suggested to use the term ‘low income countries’ rather than ‘developing countries’. 7. References should be reviewed to check for their completeness. Conference presentations usually are not considered publications. Specific comments: 1. Para 6. …independent verification of beam calibration – it is suggested to refer to the IAEA publications on the IAEA/WHO TLD postal audits 2. Sec 2.1 Here is the room to add a sub-section on the role of quality audit as part of quality management including the appropriate references, e.g. by ESTRO, AAPM, IAEA (‘Setting-up a radiotherapy programme…’ ‘Comprehensive audits of radiotherapy practices…, and papers on the IAEA/WHO TLD postal dose audits as well as papers by RPC, Houston, on credentialing/dosimetry audit) 3. Para 16, last sentence. Rather than “qualification” of staff, perhaps “relevant training and competence” of staff. 4. Para 19 seems misplaced. What is meant by ‘conventional therapy’? Clarify. Revise ‘…such as suitable in-vivo dose measurement systems may not be commonly available for IMRT…’ 5. Para 20, last sentence: “inefficient” should be “ineffective”? 6. Para 21, 2nd and 3rd sentence: logic is missing? 7. Para 22, There is no such thing as ‘absorbed dose calibration’. Use ‘beam calibration’ or ‘absorbed dose determination’. Refer to the IAEA/WHO TLD audits. Reference to Sec. 3.3.1 is not correct. 8. Para 24, ‘extremely low’ replace with ‘lower’; give reference to TLD audits, such as IAEA and RPC-Houston. 9. Para 25, severe reported accidents, give references. 10. Para 26, refer to IEC, AAPM and ESTRO publications 11. Para 27, refer to the IAEA report on the Panamanian TPS accident 12. Para 28, give references 13. Para 30, MU calculators for IMRT exist and some are commercially available 14. Para 31, EPID based in vivo dosimetry systems are used for IMRT, those in conjunction with cone-beam CT offer a 3 D dose determination. Diode based in-vivo dosimetry for IMRT in conjunction with a model based MU verification tool has been developed for IMRT by a Swedish group under the ESTRO umbrella. 15. Para 33, Using the patient photograph is not allowed is some countries for various reasons; suggest ‘is advisable’ rather than ‘indispensable’. This is included in the IAEA QUATRO guidelines, which may be referred to here. 16. Chapter 3. Remove multiple repetitions and lots of redundant information. 17. Para 40, incorrect reference to chapter 4. 18. Para 45, ‘no longer acceptable’, replace with ‘no longer applicable’. 19. Para 46, rephrase the 1st sentence, emphasizing that the national protocols need to be followed locally. Fig. 2.1. Is the number and caption correct? JNCI or INCI? 20. Para 50, remove the 2nd sentence; what is meant by ‘vomiting… and avoiding a collision’) 21. Para 51, ‘encourage people’? 22. Para 54, last two sentences: these do not seem to fit the sub-title of the paragraph. Footnote 2; ‘different examinations’ 23. Para 55, ‘all properties’. Clarify. 24. Para 56, ‘becoming significant’; give example; ‘CT based treatment planning preparation’ 25. Para 57, End of para, a confusing description; What is meant by ‘the beam axis between distant slices’? A non-coplanar beam across a top section…? 26. Para 59. The definition of the risk indices seems muddled as written. The indices seem to belong to Section 5, anyway. 27. Para 60, what is meant by ‘all systems fail under special circumstances’? What are the ‘special circumstances’? 28. Para 66, is this a speculation or the facts supported by evidence? 29. Para 69, ‘shift is validated (or not)’ replace with ‘verified’. 30. Para 74, 2nd sentence: add “temporal response” to the detector attributes in parentheses? Refer to small beam dosimetry work by the IAEA. 31. Para 94, 1st sentence: “training” rather than “qualifications”? And last sentence: “dosimetric effects” rather than “physical effects”? 32. Para 156, Thomadsen 2003 is not on the list of references 33. Para 162, incorrect reference to Appendix 34. Para 163, What is meant by ‘global experience’ and ‘opinion of local experts’? 35. Para 178 – 179, Hierarchy of sub-headings 5.5.2.2 and 5.5.2.3 is unclear – are they at the same level? Is this PSA or FMEA? Table 5.1: where the percentages are from? What ‘individual/cumulative contributions’ mean here? 36. Where do the factors in para 181-184 come from? What are the nine initiating events? 37. Bold text after para 207, 3rd bullet point: this is the first mention of “moderated electronic FORUMs”, and the previous mention of “panel of experts” was in the context of FMEA. Conclusions should not bring in new material. 38. Para 209, 2nd sentence: it is odd having an example in a conclusion.