|1. Introduction and General Comment
2. SRP welcomes this opportunity to comment on the ICRP Draft Recommendations via the IRPA consultation exercise. We recognise the importance of this document for the future of radiological protection, and hence it is vitally important to ensure that the recommendations are thoroughly reviewed by the practitioner community prior to their adoption by ICRP. ICRP are to be congratulated for seeking the continued involvement of IRPA as they develop their thoughts.
3. The June 2006 draft represents a considerable improvement over previous versions of the draft recommendations, and many of the previous concerns have been appropriately dealt with. The current draft has been well received by SRP’s members, with broad endorsement of the key approaches. There are however several areas where we consider that further development and /or clarification is necessary in order to deliver a fit-for-purpose set of coherent recommendations which can form the basis of the future of practical radiological protection.
4. We have focussed our comments on the five principal questions posed by ICRP in the text. We have also added comment on other key areas of interest, together with some detailed comment on the text where we consider this to be particularly helpful.
5. Question 1: Scope, Exclusion and Exemption
6. We welcome the delineation between planned, emergency and existing situations which we consider uses terminology which is well understood. The extent to which there is value in continuing also to use the previous terminology practices and interventions at the same time requires careful consideration – there is a potential for overlap which may be unhelpful. The current draft seems inconsistent in its use of these terms.
7. Whilst the thrust of the arguments regarding exclusion and exemption are correct, the formulation used to underpin exemption requires review as it appears to be stated in the wrong order, thereby giving a false emphasis to risk/dose considerations. As stated in para (46) the key principle is the avoidance of unwarranted control, and the reasons for this are not limited to triviality of risk (and dose). Hence the stated principles for exemption in para (45) are secondary in nature and should clearly be seen as such. Perhaps the order of paras (45) and (46) should be reversed? In para (45) it would be helpful to have separate principles for the need for practices to be justified and the need for sources to be inherently safe - these two concepts are not related.
8. We note that ICRP have issued a separate consultation document on the subject of Scope. Whilst the specific issue is not covered directly in the June draft recommendations, we would like to emphasise the importance to the practioner of establishing an absolutely clear, simple and understandable basis for the exemption/clearance of solid materials from regulatory control. This is by far the dominant practical issue in this context, and ICRP must provide a framework for the derivation of a single set of activity concentration values [Bq per Kg] which is capable of public understanding and confidence, and is not undercut by secondary issues and the unnecessary definition of other numerical values (eg exclusion values) which would have the potential to generate confusion.
9. In recognising the need to establish pragmatic approaches to exclusion and exemption on the basis of inability to control or unwarranted control, it would be helpful to extend this argument to move towards establishing a more general basis for the lower boundary of the radiation protection system of control. This would assist practitioners to focus on those situations which merit attention and hence minimise effort in addressing issues of no real merit.
10 Question 2: Justification
11. We agree that justification falls within the sub heading Source Related in para (185), and that such a distinction is helpful.
12. We believe that it is fundamentally important to retain the principle of Justification, and we consider that the treatment in the current draft gives the correct sense and weight to this topic. In particular we support the requirement for justification to be considered generically, ie by type of practice or activity. However, whilst the final sentence in para (190) is self evident [Radiological protection considerations will be important to a greater or lesser extent …], our experience indicates that in almost all situations radiological issues are minor compared to other factors. Indeed, the formal inclusion of the concept of justification in radiological protection philosophy and regulation has in practice served to highlight and unduly emphasise the radiological risks and set them apart from other hazards which in practice may be more important. Hence it is important that para (190) emphasises the broad all-encompassing nature of justification and that potential radiological hazards are only one (probably small) factor in the considerations
13. There is strong support for the specific attention given to the justification of medical exposures. In para (247) it is important to emphasise that an individual patient exposure can only be justified if the outcome of the delivery of the exposure is evaluated for the benefit of the patient. In diagnosis this means that a clinical evaluation of the image acquired must be carried out otherwise the exposure is not justified.
14. Question 3: Optimisation
15. The draft recommendations appropriately highlight the central importance of optimisation as the cornerstone of practical protection. However, the descriptive wording associated with the concept has become over-indulgent and unnecessarily complex. Para (193) adequately and appropriately expresses the necessary definition, which remains focussed on the well-recognised and respected ALARA terminology. Other expressions such as the ‘principle’ statement in para (185) are unnecessarily complex: in particular the use of the term best protection option under the prevailing circumstances does not add any value.
16. We fully agree with the sentiment expressed in para (194) that optimisation must reflect the role of individual equity, safety culture and stakeholder involvement. This is in line with considerable UK experience in this field over many years, and the artificially narrow interpretation of optimisation resulting from the older referenced ICRP reports is not representative of recent or current practice.
17. We particularly support the comments on the limitations and usage of collective dose in paras (229) to (231), and also in paras (57) and (145) to (148). The use of collective dose in societal decision making processes does need circumspection if equity is to be maintained with the treatment of other hazards which are not amenable to equivalent assessments.
18. Para (226) discusses whether it is possible to determine a dose level below which optimisation should stop. Whilst we agree that this is difficult to decide a priori, it would be appropriate to indicate that the greatest attention should be focussed on those situations where the exposures are closest to constraints and that there is clearly a situation of diminishing returns in terms of health benefit when exposures are insignificant compared to other generally unavoidable exposures. This supports the previous comment on the need to give more thought to establishing a more general basis for a lower boundary to the system of control.
19. Para (227) is helpful in emphasising that optimisation is not minimisation.
20. In para (248) the second sentence could be usefully expanded to state “In diagnosis, this means avoiding unnecessary, or greater than necessary, exposures, while in therapy…” further emphasising the need for an integrated approach to justification and optimisation in diagnostic exposures.
21. The interaction between optimisation and constraints is critical - indeed they are integrally bound together as illustrated by the optimisation process outlined in para (196). Our comments on constraints are addressed in the following section.
22. Question 4: Constraints
23. We agree in principle with the use of source-related constraints as a key component of the prospective optimisation process. However, the key issue in practical implementation is the extent to which constraints are regarded as de facto ‘source limits’ - in effect having the same status as limits in terms of operational compliance. Where constraints are prospectively set in advance of operational activity, presumably on the basis of generic optimisation considerations as outlined in para (210), there will be a strong tendency to regard the numerical constraint as the operational limit, regardless of actual experience. This could lead to a mis-allocation of resource aimed at compliance with a perceived ‘limit’. It is therefore essential to give further clarification of the status of constraints in relation to operational activities, and to emphasise more strongly the need for continued review of the choice of the constraint during the operational life of an activity.
24. This problem is particularly acute in dealing with occupational exposure, where operational control is principally based on assessing the total dose to workers from all relevant sources. Such control, including the integral ALARA process, sometimes takes account of knowledge of exposure to specific activities within the work programme, but in practice it is the total exposure which is the key control parameter. Hence ICRP’s emphasis on constraints as the most fundamental level of protection does not fully align with operational practice for occupational exposure.
25. These points emphasise the need for further reflection on the relationship between constraints and limits, and on the role of prospective constraints during ongoing operations and retrospective analysis.
26. We agree with the proposed approach that the selection of the specific value for the constraint may be established by a process of generic optimisation that takes account of national or regional attributes and preferences together, where appropriate, with a consideration of international guidance and good practice elsewhere (para 210). We also support the approach in para (203) et sec on defining numerical values within three broad bands based on relevant attributes, although we would encourage the re-introduction of a minimum value to the first band [ie the ‘under 1 mSv’ band] as part of the suggested consideration of the lower boundary to the system of control.
27. However, given the above broad approach to the setting of numerical values for constraints and the emphasis on the need for local involvement in the process, we disagree with ICRP’s re-adoption of detailed numerical constraints in the specific field of waste management - ie 0.3 mSv and 0.1 mSv taken from Publications 77 and 82. ICRP’s adoption of these values and their scientific underpinning, together with the associated value judgements, has not been subject to the rigorous review and consultation process now espoused so strongly by ICRP. Whilst the numerical values are not unreasonable in a UK context, their re-adoption by ICRP at the international level seems to go against its fundamental approach whereby constraints should be established by a process of generic optimisation that takes account of national or regional attributes and preferences (para 210 as above). It is therefore essential that such constraints should be defined at the local/national level with involvement of relevant stakeholders. Appropriate text could read “The Commission now recommends, in conformity with the principles expressed in para (210), that these specific values are used for guidance subject to consideration of national or regional good practice”.
28. Question 5: Natural Sources
29. The approach to natural sources is broadly supported.
30. There is debate in paras (291) and (292) on the unconstructive division between natural and man-made/artificial sources and the resulting dichotomous scale of protection. Despite appearing to regret this position, the approach of ICRP is then to embed and re-inforce the dichotomy. Whilst acknowledging that this is a difficult situation and reflects differences in both source controllability and public perception, it is unfortunate that ICRP take such a passive line without any proposals as to how the dichotomy could be ameliorated or addressed in the longer term. The principal concern here is ICRP’s apparent re-inforcement of the perception that artificial sources require particularly tight control compared to natural sources, which we do not believe to be the intent. Note that this issue is compounded by para (341).
31. It is not clear how para (295) relates specifically to natural sources. The para is more generally applicable and should perhaps be included in the section on Scope. Paras (296) and (297) seem to relate more to Section 3 on biological aspects and risks.
32. Other Principal Issues
33. Section 10; Protection of the Environment
34. Given the ongoing programme of work by ICRP and the other international agencies on the protection of the environment it is appropriate for the General Recommendations only to address the top tier approach as in the current draft. As part of the objectives of environmental protection in para (352) we would support the re-insertion of reducing the frequency of early mortality which was included in a previous draft and is an important objective.
35. In developing ICRP’s forward work in this field it is important to give substance to the statement in para (352) reflecting the need to retain a sense of proportion. There is some concern within the UK that the overall construction of reference animals/plants and its potential for ultimate integration into regulatory systems could lead to a disproportionate burden in demonstrating compliance. Para (351) correctly notes that for current practices there are no specific concerns about environmental effects. ICRP, in partnership with the other international agencies, must therefore continue to be mindful of the need for the developing framework for environmental protection to be capable of simple and proportionate application.
36. Section 6: Medical Exposure of Patients
37. The general structure and content of this section are considered to be helpful and appropriate.
38. Para (250) should encourage particular attention to be given to the justification of medical exposures to children and pregnant women.
39. Para (252); Add after the last sentence “In considering the optimisation of protection, both dose and image quality commensurate with the medical purpose must be taken into account”.
40. Paras (255) and (259) both address the issue of low doses in diagnostic exposure. It is not clear that reference levels can effectively address this issue. The text should emphasise the importance of routine quality control of both dose and image quality so as to ensure that both dose and image quality are commensurate with the medical purpose.
41. Paras (270/271); The administration of unsealed radionuclides, whether for diagnostic or therapeutic purpose, should be conducted in an environment where doses to staff, members of the public, patient’s relatives and facility workers is minimised. This is particularly important in cases where the administration of unsealed radionuclides occurs in places other than a specialised nuclear medicine department in a hospital.
42. Other Significant Textual Comment
43. Para (30): It may be helpful in the first sentence to emphasise that safe is not synonymous with no risk.
44. Para (159): The final sentence is unhelpful - as indicated above, constraints are totally integrated within the optimisation process and cannot be divorced from it.
45. Para (214) implies that dose limits apply to existing exposure situations – compared to para (186) which states that limits apply to planned situations. The UK and the EU apply protective measures, including occupational dose limits, to identified work activities involving a significant increase in exposure due to natural radiation sources.
46. Para (233) should recommend the involvement of relevant stakeholders in the optimisation process, as well as the authority and the operating management.
47. Para (245) the sentences “Thirdly, radiotherapy aims to destroy the tumour tissue. Some functional damage to surrounding tissue and some risk of stochastic effects in adjacent non-target tissues are inevitable but should be minimised by the use of appropriate techniques and optimisation” seem out of place in this paragraph (which discusses the relationship between the patient and staff).
48. Para (258) relating to radiotherapy optimisation is out of place in a section (6.2.1) on diagnostic reference levels.
49. Section 7.1 seems largely tutorial in nature, and whilst not unhelpful may be out of place in a recommendations document.
50. Paras (321) and (323): Safety culture, sound engineering principles, experience and defence in depth are relevant both to potential exposures generally and radiotherapy specifically.
51. Para (332); The list of accidents is out of place and should be deleted.
52. Section 9 combines emergency situations and existing situations which may be better separated for clarity.