REPORT OF THE TECHNICAL MEETING: THE NEW DOSE LIMIT FOR THE LENS OF THE EYE IMPLICATIONS AND IMPLEMENTATION VIENNA, 2-4 OCTOBER 2012

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1 REPORT OF THE TECHNICAL MEETING: THE NEW DOSE LIMIT FOR THE LENS OF THE EYE IMPLICATIONS AND IMPLEMENTATION VIENNA, 2-4 OCTOBER 2012 Introduction A Technical Meeting on the The new dose limit for the lens of the eye implications and implementation was held at the IAEA in Vienna. A copy of the agenda is attached to this report. The meeting was attended by 47 experts: representatives of Australia, Belgium, Canada, China, France, Germany, Greece, Iceland, Indonesia, Italy, Japan, Lithuania, the Netherlands, Norway, Pakistan, Philippines, Poland, Russian Federation, Slovakia, Spain, Sweden, Ukraine, United Kingdom, United States of America and Vietnam; and representatives from the following international organisations: European Commission (EC), European Nuclear Installation Safety Standards Initiative (ENISS), International Commission on Radiological Protection (ICRP, International Society of Radiology (ISR), Pan American Health Organization (PAHO), United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), World Health Organization (WHO), and the World Nuclear Association (WNA). The meeting was opened by Mr Pil-Soo Hahn, Director of NSRW. The meeting was chaired by Mr Sigurdur Magnusson, Iceland. Mr Hahn noted in his opening remarks that the Technical Meeting would not debate the scientific basis for the new dose limit. The purpose of the meeting was to discuss guidance on implementing the requirement for the new dose limit, and the output of the meeting will form the basis of guidance to be provided to Member States. The intention is to publish the guidance as a TECDOC in In the longer term, the guidance will form the basis for the guidance in relation to the new dose limit for the lens of the eye in the Safety Guides DS453: Occupational Radiation Protection and DS399: Radiation Safety in the Medical Uses of Ionizing Radiation. Introductory presentations were made by the ICRP on the scientific basis of the new dose limit for the lens of the eye, and on the process for establishing the new dose limit. Three presentations on the practical issues for implementing the dose limit to the lens of the eye were made in relation to medical; industrial; and nuclear facilities. The expected timelines for the development of the TECDOC are as follows: Draft TECDOC to be prepared following the IAEA process for developing TECDOCs; Draft 1 to be sent to the participants in the Technical Meeting by early March for comment; Draft 2 to be sent to RASSC in May; Draft 3 to be sent to Publishing Section in July for publication. Discussion at the Technical Meeting focussed on the following issues:

2 General issues: 1. The TECDOC should include reference to the ICRP publication 118 regarding the new dose limit for the lens of the eye 2. The TECDOC should include the old dose limit and the new dose limit early in the document. 3. The TECDOC could include presentations from this meeting 4. The TECDOC should provide generic information applicable to all practices. 5. Most of the issues presented below are components of the radiation protection programme for workplaces. The TECDOC needs to focus on the additional measures for protection of the lens of the eye to be implemented for each of these issues. Which categories of workers are at risk of elevated doses to lens of eye The following points should be included in the TECDOC: 1. Each licensee should review the safety assessment to identify if any workers are at risk of an elevated dose to the lens of the eye. The safety assessment should identify those workplaces where the dose limit to the lens of the eye will be more restrictive than the dose limit for the whole body. It should then identify particular means for optimization of protection for the lens of the eye and the best monitoring strategy. 2. Workers that are at risk of elevated doses to the lens of the eye fall into the following categories: a. Workers that receive elevated whole body doses and are uniformly exposed to radiation in their work b. Workers who are uniformly exposed to radiation, or who are non-uniformly exposed to radiation, and are either: i. protected by fixed shielding, but whose eyes are either not protected, or are protected by lower level of shielding ii. protected by personal protective equipment e.g. lead aprons, but whose eyes are not protected to same extent 3. The TECDOC should not include a list of worker categories that are at risk of an elevated dose to the lens of the eye, but to provide the following as examples. A generic safety assessment may indicate that the workers in the following areas are at risk of elevated doses to the lens of the eye a. Medical facilities: i. staff working in close proximity to patients in image guided interventional procedures (list of occupation categories listed in the ICRP Publication 113); 1. The workload of the workers is very important, and for some specialists in the ICRP 113 list, they may carry out very few procedures per month 2. The list includes nurses, technicians, other professionals ii. staff carrying out some activities in nuclear medicine; preparation of sources/radiopharmacueticals, PET/CT iii. manual brachytherapy

3 iv. CT guided biopsy v. cyclotron engineers b. Industrial facilities: i. industrial radiographers c. Veterinary radiology d. Nuclear facilities: i. glove box workers ii. decommissioning workers iii. Pu/DU handling and QA iv. MOX fuel fabrication, v. Workers undertaking maintenance activities in NPPs and other types of nuclear facilities. 4. Is it necessary to consider exposure to neutrons a. Are non-uniform neutron fields found with the handling of Pu b. There are uncertainties with measurement of neutrons 5. Exposure to beta particles may be an issue in nuclear medicine and in NPPs. 6. For some categories of workers identified in point 2 (above), complying with the new dose limit may pose certain difficulty. Dosimetry would be necessary to demonstrate compliance. 7. Design of workplaces / equipment / personal protective equipment The following points should be included in the TECDOC: 1. Protection measures are more important than making measurements of doses 2. Extra shielding and protective glasses should be sufficient to reduce doses to workers in the nuclear industry who may potentially receive doses to the lens of the eye over 20 msv. 3. Protection provided by industrial safety glasses needs to be evalated 4. Protective eyewear : the correct equipment must be selected, and then training provided in its proper use Medical facilities interventional radiology etc: 5. IEC equipment standards for medical equipment a. Under table tube versus over table tube 6. The medical equipment available in some countries is not the same as in Europe. a. Protective systems such as suspended screens, under table curtain, fluoroscopy modes are treated as optional add-on in some countries the protective equipment should be offered with the x ray system, and not as optional addons exhaustive list to be included in an Annex b. Difficult to get the resources to purchase the protective tools after the facility is in operation

4 c. IEC standard patient dosimetry, but not covering additional protective system for workers refer to IEC Importance of personal protective equipment is covered in ICRP Publication 113 it must be provided 8. In the design of equipment for interventional radiology, there is a need to have more than one protective screen a. It was noted that this is already required in some countries 9. Health technology assessment at the country level needs to include protection of lens of the eye 10. Glasses are currently not well marked regarding the lead equivalent. Refer to IEC standard. Side shields for glasses; only for low energy electrons as bremsstrahlung will be an issue with high energy electrons. 11. There is an IEC standard currently being developed that will include standards for eye glass protection: IEC TC 62: IEC : Protective devices against diagnostic medical x radiation. It is expected to be completed in 1-2 years. 12. Use of interventional procedures on C-arm. Specific operational rules in workplaces 1. These following points are all generic challenges the TECDOC needs to focus on the additional protection required for the lens of the eye. 2. The importance of workers wearing dosimeters needs to be stressed. 3. It was noted that during a complicated procedures, there are difficulties in using protective glasses and protective screens 4. It was noted that workers can work in several workplaces, and that information on the doses received are not shared between employers, and are not added to provide the annual dose of the worker. The data should be submitted to a national dose register. 5. It was noted that at present, dosimeters are not worn consistently by all workers. This leads to a loss of information for retrospective evaluation of doses. 6. The rules for protection of staff must not lead to a reduction of protection of the patient. Clinical outcome for the patient is of highest concern. 7. The performance of medical equipment should be checked at required intervals to ensure optimum performance. Specific training of workers 1. The list of people requiring training (on protection of lens of the eye): a. Qualified experts b. Radiation protection officers

5 c. Medical physicists d. Workers (includes medical doctors, nurses, etc) who may be at risk of elevated doses to the lens of the eye e. Staff of regulatory bodies f. Equipment service engineers g. Other workers with potential to exceed the dose limit 2. The regulators should enforce training requirements. 3. An assessment of the effectiveness of training should be made. [Training programmes should include a final examination on the training.] 4. The training in medical area should be linked to training on protection of patient they are closely related 5. Training should include the general radiation protection practices of distance, shielding, and time. 6. Training should cover basic concepts of safety culture 7. IAEA should develop a training package on what should be covered in the training, including what is in the ICRP report. 8. Training should cover where to wear dosimeters 9. Training should cover how to use personal protective equipment e.g. fitting of protective glasses 10. It was considered that the requirement for the new dose limit can be met if good radiation protection training is implemented and radiation protection tools, including personal protection equipment, are properly used. 11. For medical facilities, there is a need to balance patient protection with protection of workers, and to consider protection of patients and or workers in the strategies for optimization of protection and safety. Health surveillance programmes addressing the issue 1. The workers health surveillance programme is required to be based on the principles of occupational health, in accordance with national requirements. 2. An eye examination is not trivial and not without risk. 3. Criteria for screening and harmonization of procedures for eye examinations are required. 4. Is an initial eye examination necessary? Would the initial examination of the eye be to determine the fitness of the worker for the work to be performed? Is an initial examination of use to the worker, or is it to protect the employer? What happens if a lesion is found? a. The advice of an ophthalmologist is required. 5. The screening of some doctors carrying out interventional procedures may be required, either every year or every second year?? What to do with results stop doctor practising?.

6 Monitoring of doses to the lens of the eye 1. There needs to be a section on monitoring and assessment of doses. 2. The reference quantity for eye lens dosimetry is Hp(3) as stated in ICRU51 in 1993, and ICRU 57 (1996). 3. Arguments on the use Hp(3) arising within technical discussions should be addressed to ICRU or ICRP. ICRU, which introduced the operational quantities for external exposures, has set up a committee in 2010: RC26- Operational Radiation Protection Quantities for External Radiation. The report is expected by early Eye lens dosimetry and Hp(3) measurements will be covered in the report. 4. Hp(3) has not been implemented in practice for routine individual monitoring. The main reason is that conversion coefficients for Hp(3)/Ka or Hp(3)/Fluence (respectively for photons or electrons and neutrons) have not been calculated, except for electrons (monoenergetic) in ICRU57/ICRP74. For area monitoring, there are no conversion ce-efficients in the literature or international standards for H (3). 5. When Hp(3) dosimeters are not available, the TECDOC can give suggestions and advice from the radiation protection point of view. In fact, in specific cases when actual workplace radiation fields are known, monitoring of the eye through Hp(0.07) calibrated dosimeters, like extremity dosimeters worn on the front of the head, or Hp(10) calibrated dosimeters worn on the trunk could be acceptable. In this case, the qualified expert should be aware that the uncertainty on the estimation of eye lens dosimetry is higher, he/she should estimate it and he/she should take this into account when looking at the dosimetric results and when formulating radiation protection statements and monitoring programmes. a. The TECDOC should provide practical advice on how to select suitable dosimeters for use particularly for low and middle income countries. The TECDOC should consider the infrastructure that is available in many countries. b. The TECDOC should include advice for regulatory bodies on how to address dosimetry 6. The TECDOC should contain a flow chart setting out when eye lens dosimetry was required in a practice, and when it was not required in a practice, and how it might be performed. 7. For medical workers in interventional procedures, lens doses should be monitored. The ICRP has recommended (ICRP-85, Avoidance of radiation injuries from medical interventional procedures, 2000) the use of two personal dosimeters (over and under the apron) could probably be enough, with the use of appropriate conversion factors. 8. It was considered that if a worker is uniformly exposed to radiation during their work (photon energy greater than 40 kv, dosimeter worn above any protective cover or coat), a whole-body dosimeter would provide sufficient information to assess the dose to the lens of the eye. 9. SSK report Monitoring the eye lens dose : effective dose is a good estimate of the eye lens dose for photons of energy greater than 200 kv. 10. In accident situations in industrial radiography, the effective dose measurement on the body would not be a good estimate of the eye lens dose. Higher exposure of the eyes lens would be very likely.

7 11. During the investigation of accidents, the whole body dose and the skin dose are assessed, so that the dose to the lens of the eye should also be assessed. The reading from the whole-body dosimeter could be used as a starting point in estimating the dose to the lens of the eye in accidental exposures. 12. The readings from whole body dosimeters could also be used as the starting point for retrospective dosimetry for the lens of the eye. 13. In some nuclear facilities, there are mixed radiation fields (photon/electron) and the ratio of Hp(10)/Hp(0.07) can be a factor of 2 at some specific places. 14. Phantom for calibration of dosimeters decision of ICRU to be discussed in the ISO standard ICRP Publication 116 includes external dose coefficients for the lens of the eye for various geometries (Annex F). 16. IEC and ISO standards on the eye lens dosimetry are under preparation. The ISO standard ISO Radiological protection: Procedure for monitoring of the dose to the lens of the eye, the skin and the extremities (title may change). This ISO standard will cover: a. Eye lens dosimetry locations to wear monitor see R. Behrens presentation slide 29 b. Types of dosimeters eye lens doses slide 30 c. Technical specifications of dosimeters extremity dosimeters for passive dosimeters and active dosimeters slide 31 d. The target date for the ISO standard is Given that the eye lens dose limit has been reduced, there is a need to foster the implementation of the reference quantity in practice. Dosimetrists should follow the international recommendations and should design and calibrate dosimeters in terms of Hp(3). 18. In the recent years, especially within the ORAMED EU funded Project, there have been scientific discussions on the quantity, on how to design a dosimeter to make Hp(3) measurements and on the suitable calibration phantom. Efforts have been made to make the conversion coefficients, for monoenergetic fields and for ISO standard radiation fields available in the open literature. 19. Practical issues relating to in field testing and accrediting dosimetry service providers to authorize dosimetry service providers for measurement of Hp(3) need to be considered. 20. The IEC standards: IEC provides technical specifications for active dosimeters and IEC provides technical specifications for passive dosimeters. 21. Recording of doses to the lens of the eye. Other Issues 1. The TECDOC should be generic for all practices. 2. Biology of the lens of the eye 3. Scientific basis for the change. 4. Communication strategy to inform workers of the change in the dose limit and to ask for resources for management to implement the changes required to comply with the limit. 5. Process for carrying retrospective analysis to determine the dose to the lens of the eye from past exposure records should be developed.

8 6. Cataract operations are the most common performed operation. What percentage increase in the number of cataracts is expected due to exposure to ionizing radiation? 7. Dissemination of information about the change of dose limit to licensees by regulatory body. 8. Ethical issues be covered in the report improvement in protection of worker may affect the protection of the patient. 9. Implementation process across countries and workers who move from country to country that may have different values for the dose limit to the lens of the eye. 10. Claims for compensation the protection provided previously was inadequate and I now have a cataract (is this within scope of document?).

9 Technical Meeting on the New Dose Limits for the Lens of the Eye Implications and Implementation 2-4 October 2012 Press Room M-building Draft Agenda am: Tuesday 2 October Wednesday 3 October Opening of the Technical Meeting P-S. Hahn, IAEA 2. Chairman s opening remarks S. Magnusson, IS 3. Adoption of the agenda 4. Administrative arrangements 5. Expectations of the Technical Meeting T. Boal, IAEA 6. Scientific Basis for the new Dose Limit for the Lens of the Eye J. Hendry, UK 7. ICRP Statement on Tissue Reactions C. Clement, ICRP 8. Process for including the new dose limit for the lens of the eye in the BSS T. Boal, IAEA 9. Practical issues for implementing the dose limit to the lens of the eye a. Medical E. Vano, ES b. Industrial R. van Sonsbeek, NL c. Nuclear H. El-Sabbahy, UK 10. Discussion on the key issues a. Which categories of workers are at risk of elevated doses to lens of eye b. Design of workplaces / equipment / personal protective equipment c. Specific operational rules in workplaces d. Specific training of workers e. Health surveillance programmes addressing the issue f. Technicalities associated with monitoring of doses to the lens of the eye g. Any other issues 9.00 am Thursday 4 October Summary of discussion and review of guidance 12. Further steps 13. Closing of the meeting