irpa 2010 proceedings: s08-p08 radiation protection of …topic 8: radiation protection of workers...

Session 8: Radiation protection of workers Oral presentationsS08

S08-01 Work management to optimise occupational radiological protection at nuclear power plants . . . . . . . . . . . . . . . . . . . . . . . 1271Schieber, Caroline; Ahier, Brian; Misumachi, Wataru

S08-02 Challenges on the radiation protection optimization of medical staff in interventional radiology and nuclear medicine: the ORAMED project . . 1278Ferrari, Paolo; Vanhavere, Filip; Carinou, Eleftheria; Gualdrini, Gianfranco; Clairand, Isabelle; Sans-Merce, Marta; Ginjaume, Merce; Barth, Ilona; Bordy, Jean-Marc; Carnicer, Adela; Daures, Josiane; Debroas, Jacques; Denoziere, Marc; Domienik, Joanna; Donadille, Laurent; Fantuzzi, Elena; Itié, Christian; Jankowski, Jerzy; Koukorava, Christina; Krim, Sabah; Mariotti, Francesca; Monteventi, Fabio; Ortega, Xavier; Rimpler, Arndt; Ruiz Lopez, Natacha; Struelens, Lara

S08-03 Increased extremity doses for staff in the preparation and administration of beta-emitters and PET nuclides in nuclear medicine . . . 1290Linder, Reto; Stritt, Nicolas

S08-04 Morphological dependence of lung counting efficiency for female workers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1298Farah, Jad; Broggio, David; Franck, Didier

S08-05 ALARA – Education for personnel involved in the plant modification process (ABSTRACT) . . . . . . . . . . . . . . . . . . . . . . . 1307Nilsson, Virva

S08-06 Reduction of dose around a storage pool by changing the position of BWR irradiated control rods . . . . . . . . . . . . . . . . . 1308Ródenas, José; Abarca, Agustín; Gallardo, Sergio

S08-07 Periodic review and update of the company ALARA program – Continuous improvement in the field of radiation protection (ABSTRACT) . . . . . . . . . . . . . . . . . . . . . . . 1318Hennigor, Staffan

S08-08 ISEMIR: a new international system for improving occupational radiation protection in medicine, industry and research (ABSTRACT) . . . . 1319Lefaure, Christian; Le Heron, John; Czarwinski, Renate; Van Sonsbeeck, Richard; Padovani, Renato

S08-09 Problems of the radiation protection and health effects monitoring in Ukrainian radiation workers (ABSTRACT) . . . . . . . . . . . . . . . . 1320Bebeshko, Vladimir; Bazyka, Dimitry; Likhtarev, Ilya; Gaevaya, Liudmila; Chumak, Vadim

Third European IRPA Congress 2010, Helsinki, Finland

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Topic 8: Radiation protection of workers Poster presentationsP08

P08-01 EPR: Comparative approach of the French and Finnish regulatory reviewing process and optimization of radiation-protection at the design phase . . . . . . . . . . . . . . . . . . . . . . . . . . 1321Arial, Emmanuelle; Couasnon, Olivier ; Latil-Querrec, Nevena; Evrard, Jean-Michel; Riihiluoma, Veli ; Beneteau, Yannick ; Foret, Jean-luc

P08-02 Individual doses monitoring for external exposure during the transportations of nuclear fuel bundles performed by Nuclear Fuel Plant Pitesti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1330Ivana, Tiberiu; Epure, Gheorghe

P08-03 Six years of radiation protection of operators in the General Electric FDG-radiopharmaceutical facility at the Joint Research Centre of Ispra . . 1339Persico, Elisa; Bielewski, Marek; Accorsi, Roberto; Abbas, Kamel; Giuffrida, Daniele; Osimani, Celso

P08-04 Radiation protection organization in the Joint Research Centre of Ispra (ABSTRACT) . . . . . . . . . . . . . . . . . . . . . . 1349Giuffrida, Daniele; Macchi, Giovanni; Osimani, Celso

P08-05 Support service of radiation protection in JRC Ispra (Italy) using the methodology applied in Spanish nuclear power plants . . . . . . . . 1350Ruiz, J. T.; Sanchez, A.; Ramos, M.; Lamela, B.; Graboleda, F.

P08-06 The pilot study of the radioactive aerosol particle size distribution in the air from the uranium mine Rožínka, Czech Republic (ABSTRACT) . . 1357Rulík, Petr; Mala, Helena; Hulka, Jiri

P08-07 The characteristic of long-lived radionuclides in the uranium mine atmosphere in Dolní Rožínka in the Czech Republic . . . . . . . . . . . . . . 1358Otahal, Petr; Burian, Ivo; Vosahlik, Josef

P08-08 ROBOSCAN: an advanced method and system that ensures a total radioprotection of the operators working with mobile vehicle scanners . . 1365Tudor, Mircea; Sima, Constantin; Bizgan, Adrian

P08-09 Special shielding solutions for the ITER neutral beam test facility . . . . . . . 1375Sandri, Sandro; Coniglio, Angela; Daniele, Antonio; D’Arienzo, Marco; Pillon, Mario; Poggi, Claudio

P08-10 Effective dose to staff from interventional procedures: estimation from single and double dosimetry . . . . . . . . . . . . . . . . . . . . . . . . 1386Kuipers, Gerritjan; Velders, Xandra L.; Piek, Jan J.

P08-11 Exposure levels of workers during some surgical procedures . . . . . . . . . . 1392Rossi, Francesco; Bertelli, Duccio; Gori, Cesare; Gugliandolo, Alessandra

P08-12 Staff doses in cardiological interventional radiography (ABSTRACT) . . . . 1398Parviainen, Teuvo; Kosunen, Antti; Lehtinen, Maaret

P08-13 Radiation doses to occupationally exposed personnel working with radioiodine and technetium . . . . . . . . . . . . . . . . . . . 1399Krajewska, Grazyna; Szewczak, Kamil; Krajewski, Pawel

P08-14 Occupational exposures from increased use of F-18 FDG in Denmark . . . . 1404Hybertz Andersen, Tina; Ennow, Klaus; Bjerkborn, Annika; Højgaard, Britta

P08-15 Control of radiation protection and occupational radiation exposure doses of medical staff in Ukraine (ABSTRACT) . . . . . . . . . . . . . . . 1408Stadnyk, Larysa; Yavon, Iryna; Panchenko, Iryna; Smirnova, Inna


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P08-16 The new method of distinguishing static exposure of individual TLD dosemeters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1409Kopec, Renata; Budzanowski, Maciej; Olko, Pawel

P08-17 Occupational radiation exposure in Poland based on results from the accredited dosimetry service at the IFJ PAN, Krakow . . . . . . . . . . 1413Budzanowski, Maciej; Kopeć, Renata; Broda, Ewelina; Chrul, Anna; Dzieża, Barbara; Kiszkurno-Mazurek, Aleksandra; Kruk, Małgorzata; Nowak, Anna; Obryk, Barbara; Pajor, Anna; Sas-Bieniarz, Anna; Włodek, Katarzyna

P08-18 Finger doses in Poland in the view of the extremity ring dosimetry results of LADIS Dosimetric Service Kraków . . . . . . . . . . . . 1418Sas-Bieniarz, Anna; Obryk, Barbara; Pajor, Anna; Kopeć, Renata; Broda, Ewelina; Budzanowski, Maciej

P08-19 Study of deterministic and Monte Carlo simulation methods for neutron and photon dosimetry at the Royal Surrey Hospital radiotherapy facility . . . . . . . . . . . . . . . . . . . . . 1422Morrissey, Craig

P08-20 Practical implications of the RELID (Retrospective Evaluation of Lens Injuries and Dose) project in the radiation protection of medical professionals (ABSTRACT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1432Vañó, Eliseo; Durán, Ariel; Ramírez, Raúl; Nader, Alejandro

P08-21 Risk of occupational radiation-induced cataract in medical workers (ABSTRACT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1433Milacic, Snezana; Djokovic, Jelena

P08-22 Setting up a whole body counting system in Portugal (ABSTRACT) . . . . . . 1434Bento, Joana; Nogueira, Pedro; Neves, Maria; Silva, Lídia; Vaz, Pedro; Teles, Pedro

P08-23 Internal dosimetry at the Institute of Atomic Energy POLATOM in Poland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1435Ośko, Jakub; Golnik, Natalia; Ciszewska, Katarzyna

P08-24 Designing and using a veterinary megavoltage X-ray facility (ABSTRACT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1442Vos, Cornelis S.; Teske, Erik; Lenstra, Johannes A.

P08-25 Beta doses from handling UO2 pellets at a nuclear fuel factory; Monte Carlo based simulations and TLD measurements (ABSTRACT) . . . . 1443Pettersson, Håkan; Ullman, Gustaf; Riber Gunnarson, Anders; Gårdestig, Magnus

P08-26 Review of the constraints of the effective dose levels at OKG NPP (ABSTRACT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1444Bauréus Koch, Catrin


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Session 8: Radiation protection of workers Oral presentations

Work management to optimise occupational radiological protection at nuclear power plants

Schieber, Caroline1; Ahier, Brian2; Misumachi, Wataru3 1 CEPN, FRANCE 2 OECD/NEA, FRANCE 3 JNES, JAPAN

Abstract In order to provide guidance to the nuclear community on the best practices of work management in nuclear power plants, the Information System on Occupational Exposure (ISOE), sponsored by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, established an international expert working group to update a report on this topic, previously issued in 1997.

The report, “Work Management to Optimise Occupational Radiological Protection at Nuclear Power Plants”, was published in 2009. It provides practical guidance based on the operational experience within the ISOE programme in the key areas of work management to optimise occupational radiation protection, including: Regulatory aspects; ALARA management policy; Worker involvement and performance; Work planning and scheduling; Work preparation; Work implementation; Work assessment and feedback; and Ensuring continuous improvement. The specific aspects of work management applicable to each of these areas are illustrated by practical examples and case studies arising from ISOE experience. This paper summarizes and describes the key messages of the report.

Introduction Occupational exposures at nuclear power plants worldwide have steadily decreased since the early 1990s. Regulatory pressures, technological advances, improved plant designs and operational procedures, ALARA culture and information exchange have contributed to this downward trend. However, with the continued ageing and possible life extensions of nuclear power plants worldwide, ongoing economic pressures, regulatory, social and political evolutions, and the potential of new nuclear build, the task of ensuring that occupational exposures are As Low As Reasonably Achievable (ALARA) continues to present challenges to radiation protection professionals.

Since 1992, the Information System on Occupational Exposure1 (ISOE), jointly sponsored by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, has provided a forum for radiological protection professionals from nuclear 1 For more information, see ISOE web site: www.isoe-network.net


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Session 8: Radiation protection of workers – Oral presentationsSchieber, Caroline et al.Work management to optimise occupational radiological protection at nuclear power plants

power utilities and national regulatory authorities worldwide to co-ordinate international co-operative undertakings for the radiological protection of workers at nuclear power plants. The ISOE objective is to improve occupational exposure management at nuclear power plants by exchanging relevant information, data and experience on methods to optimise occupational radiation protection.

Key to effective occupational exposure management has been the widespread understanding of the need for careful planning and execution of refuelling and maintenance outages. This approach, referred to as work management, stresses the importance of approaching jobs from a multi-disciplinary team perspective, and of following jobs completely through all stages from conception to post-job follow-up.

In order to provide guidance to the nuclear community on the best practices of work management, ISOE established an international expert working group to update a report on this topic, previously issued in 1997. This recognises that while work management is no longer a new concept, continued efforts are needed to ensure that good performances, outcomes and trends are maintained in the face of current and future challenges.

The report, “Work Management to Optimise Occupational Radiological Protection at Nuclear Power Plants”, was published in 2009 (NEA, 2009). It provides practical guidance based on the operational experience within the ISOE programme in the main areas of work management. The specific aspects of work management applicable to each of these areas are illustrated by practical examples and case studies arising from ISOE experience.

Principles of work management Work management is a comprehensive and iterative approach to work. The philosophy of work management is a continuous loop that consists of planning, preparation, implementation, assessment and follow-up in order to make the overall work progressively optimised and using a multi-disciplinary team approach involving all relevant stakeholders (see Figure 1). Feedback is a key component, and such feedback should be obtained both locally and globally. Assessment and feedback is the final stage of work and, at the same time, the first stage of the process. However, work management is also forward looking. Therefore, recognising the constant evolution of many parameters that are included in the above topics, such as ongoing technological advances, as well as using past and current lessons to not only inform future work but also future design and operations, the report closes with a chapter on “Ensuring Continuous Improvement”.


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Worker Involvement

and Performance

Regulatory Aspects

ALARA Management Policy

Continuous Improvement

Work Planning

Work Preparation

Work Implementation

Work Assessment

and Feedback

Figure 1. Work management elements and their iterative nature.

Regulatory aspects While it is the licensee’s duty, in the first instance, to ensure that a particular operation is safe from the perspective of nuclear safety and radiological protection, this must be done within the applicable regulatory framework.

National regulatory frameworks are based on radiation protection principles and standards developed at the international level. They aim to secure the maintenance and improvement of safety at civil nuclear installations through regulations addressing nuclear safety, and ensure the protection of workers, public and environment from ionising radiation through regulations addressing radiation protection. Such regulation provides for an effective radiological protection infrastructure which includes a “safety culture” shared by those with protection responsibilities from workers through to management.

In the field of safety, there is an effort to develop and implement “performance based” plant maintenance rather than prescriptive pre-scheduled maintenance. This typically allows reductions in maintenance volume and therefore occupational exposure. In the field of radiation protection, specific rules can be introduced to foster the optimisation of radiation protection. In addition to the regulatory framework, utilities can develop their own radiation protection internal rules, integrating operational restrictions for the management of individual and collective doses.


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ALARA management policy The ALARA approach consists in always questioning whether the best has been done in the prevailing circumstances, and whether all that is reasonable has been done to reduce doses (ICRP 2007).

In order to spread the ALARA “way of thinking” amongst all levels of the management chain, from the company President to the worker on the floor, it is necessary to set up and structure dedicated ALARA programmes that make explicit the goals and objectives of the utility regarding optimisation of radiation protection. The responsibilities associated with the implementation of the ALARA programme should be clearly distributed among the various management levels and work specialisations. The creation of ALARA Committees or other types of specific ALARA organisations are a key element, forming “meeting points” between the main actors in ALARA implementation. This favours their involvement in the ALARA programme as well as the common elaboration of ALARA plans. Finally, plant management must be willing to support, in policy and budget, a multi-disciplinary team approach to plan, schedule, implement, and follow-up jobs.

Worker involvement and performance ALARA cannot be achieved without worker involvement. It is the worker that is exposed, and it greatly depends on the worker himself to reduce the exposure. The involvement of workers at all levels is one of the most important aspects of an effective work management programme. By engaging the worker in the task being performed, the worker is more likely to be motivated to perform the job to the best of his/her abilities, and this will be reflected in lower job doses as well as in higher job quality. To ensure the full involvement of workers, conditions should favour the creation and continuation of such involvement. It should also implicate workers at all the stages of a job (planning, scheduling, preparation, implementation, follow-up) and assure that there is a mechanism for matching individuals and their skill levels with appropriate tasks.

It is also important to improve worker performance for ALARA implementation. This requires an appropriate level of education and training to ensure that workers possess the correct tools and competencies. Involvement of all levels is also necessary: senior and mid-level management, job foreman, shift supervisors, etc. Good communications between different levels of the hierarchy and among the different disciplines should be a management priority.

Finally, top management must also be committed to this process and favour a structure that encourages and takes into consideration the feedback of workers. Worker incentive programmes will help to improve and maintain worker motivation and involvement, and should pay for themselves in terms of savings in time, dose and costs, and in job quality.

Work planning and scheduling The planning stage is an essential period within which to implement work management actions and optimise radiation protection.

Work activities must be carefully planned to ensure that radiological protection is optimised. Work planning and scheduling should integrate radiation protection criteria and use feed-back experience and benchmarking to ensure that the most effective


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approaches are implemented. Planning must recognise not only the sequence of job steps, but also their relationship and their multi-disciplinary nature. The location of job planners can be optimised by centralising all appropriate workers (planners, engineers, schedulers, etc.), thus fostering and facilitating interdisciplinary communications. In addition, the proper scheduling of jobs to co-ordinate the use of services, scaffolding, installed shielding, water shielding in pipes and tanks, etc., and the use of scale models for planning purposes (as well as training and worker orientation) contribute to the efficient use of resources.

Particular attention should also be paid to the optimisation of outage duration. Key issues in the selection of work include the use of realistic assumptions when deciding upon the necessity for performing work, the selection of only those jobs which are “necessary” to the safe and efficient running of the plant and the implementation of a tight but not rushed schedule to reduce the risk of rework.

The scheduling of jobs in relation to each other, the identification of potential work interferences and hazards in the work zone, and the identification of dose intensive jobs are critical to the optimal use of resources and job success.

Finally, the planning stage should also integrate actions for the preparation of personnel, such as pre-job briefings or mock-up training, in order to improve worker performance and reduce occupational exposure.

Work preparation The success of work greatly depends on the quality of the preparation. Work preparation in the context of this report covers all activities considered or performed before and during a job in order to prepare the site and the work crew. It addresses factors affecting the source term, the duration of work and the number of workers exposed.

Source term removal, decontamination, reduction by shielding or continuous control are effective for achieving dose rate reductions. Various tools and equipment that support work implementation are also appropriate. It is important to take advantage of these techniques as part of work preparation since many effective methods have been developed and a great deal of experience has been accumulated. Finally, support tasks such as optimisation of the work schedule and job co-ordination in the work area are also key components of work preparation.

Work implementation The work implementation phase refers to the actual performance of the work and to those actions taken during this time which affect or facilitate the work.

There are several areas where work management can effectively contribute to lowering dose as well as time and cost. These includes organisational aspects such as the presence of radiation protection personnel and specific procedures and technical aspects such as remote monitoring and access control systems. Efficient work process control will help to assure that the objectives set during the work planning phase are met. The reduction of transit exposure and unnecessary dose will be facilitated by providing workers with sufficient radiological, plant and job specific information. Finally, the collection of feedback information will assist in real-time work management and facilitate the preparation of future work.


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Work assessment and feedback The philosophy of work management is a continuous loop that consists of scheduling, planning, implementing, assessing, following-up, making modifications as per lessons learned and repeating the process for the next job to be undertaken, thus making the work cycle progressively optimised and in line with current technological developments. "Assessment and feedback" is the final stage of work and, at the same time, the first stage of the continuous loop.

In a generic approach, two levels of information may be necessary to provide complete feedback on work implementation: the “internal” level, which consists of an analysis of in-plant performances, and the “external” level, which will provide national and/or international data favouring the exchange of new ideas and allowing the plant to assess its position with regard to other plants of the same type.

In terms of post-job review, it is essential to have a multi-disciplinary team conduct the review and to include as much direct input from the workers, including contractors, as possible. The follow-up of recommendations and lessons learned should then, ideally, be performed by the same multi-disciplinary team which conducted the post-job review.

Normally, follow-up will lead directly into the next implementation of the operation under consideration such that a certain closure (job conception, scheduling, planning, implementation, assessment and follow-up, job modification as per lessons learned, scheduling, planning, etc.) occurs and the job becomes progressively optimised and appropriately modified to keep up with current technological developments.

The lessons-learned, both good practices and areas for improvement, should be collected in a diligent manner, and exchanged not only with the work team but also with colleagues at the plant, industry and international levels. RP managers should recognise all available information sources and use them effectively as well as share their own information and experience.

Finally, work management implementation should be audited periodically to assure that it is functioning properly.

Ensuring continuous improvement While work management is an iterative process, it is also forwarding looking, seeking continuous improvement and continuous vigilance to ensure and maintain a high level of radiation protection. Such improvements therefore seek to incorporate, through information and experience exchange, lessons learned and ongoing technological advances to not only inform future work activities, but also in the longer term, new design, new build and new operations to ensure that doses are maintained ALARA.

In addition to experience exchange through programmes such as ISOE, there is a range of new technologies in various fields relevant to exposure reduction. These include technologies addressing source term reduction, decontamination, and mechanisation, automation and remote monitoring. The development and further application of such technologies should be considered in light of the radiation protection issues that will become important in the future, including exposure reduction in newly constructed or newly designed plants (of potentially increasing importance), large-scale modification works expected to be needed in association with aging and lifetime extension of nuclear reactors, and reactor decommissioning.


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Conclusion Safety and radiation protection are the most important factors for the safe operation of nuclear power plants. Experience in occupational radiation protection has shown that radiation protection measures should be adopted in all phases of the nuclear power plant life cycle, from design to operation to decommissioning. This not only allows source term removal or reduction as part of design, but also consideration of how exposure reduction methods or procedures can be most effectively implemented during operation.

Many methods that can be considered by all those with a role in occupational radiation protection at nuclear power plants have been described in this report. This multi-disciplinary, practical experience in work management, based on lessons drawn from many years of nuclear power plant operations, in addition to approaches that are still under development or will be realised in the future, are important elements in the optimisation of occupational radiation protection and for ensuring continuous improvement in the face of current and future challenges and opportunities.

Acknowledgement The authors would like to thank all members of the ISOE Working Group who contributed their knowledge and experience to the elaboration of this report.

Reference NEA, Work Management to Optimise Radiological Protection at Nuclear Power Plant,

NEA N°6399, OECD 2009. (available for download from http://www.isoe-network.net/index.php?option=com_content&view=article&id=170&Itemid=162)


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Challenges on the radiation protection optimization of medical staff in interventional radiology and nuclear medicine: the ORAMED project

Ferrari, Paolo1; Vanhavere, Filip2; Carinou, Eleftheria3; Gualdrini, Gianfranco1; Clairand, Isabelle4; Sans-Merce, Marta5; Ginjaume, Merce6; Barth, Ilona7; Bordy, Jean-Marc8; Carnicer, Adela6; Daures, Josiane8; Debroas, Jacques4; Denoziere, Marc8; Domienik, Joanna9; Donadille, Laurent4; Fantuzzi, Elena1; Itié, Christian4; Jankowski, Jerzy9; Koukorava, Christina3; Krim, Sabah2; Mariotti, Francesca1; Monteventi, Fabio1; Ortega, Xavier6; Rimpler, Arndt7; Ruiz Lopez, Natacha5; Struelens, Lara2 1 ENEA, Radiation Protection Institute. ITALY 2 SCK/CEN, Belgian Nuclear Research Centre, BELGIUM 3 GAEC, Greek Atomic Energy Commission, GREECE 4 IRSN, Institute for Radiological Protection and Nuclear Safety, FRANCE 5 CHUV, University Hospital Centerand University of Lausanne, SWITZERLAND 6 UPC, Institute of Energy Technologies-Universitat Politècnica de Catalunya, SPAIN 7 BfS, Federal Office for Radiation Protection, GERMANY 8 CEA, Laboratoire National Henri Becquerel at the Commissariat à l'Energie Atomique, FRANCE 9 NIOM, Nofer Institute of Occupational Medicine. POLAND

Abstract The development of an up-to-date radiation protection system for medical staff working with radiations requires data on field (type of radiation, energies, scattering materials...), exposure (time, activities, position of operator..) and protective devices (barriers, glasses, gloves and aprons) which are only partially available in the radiation protection routine practice. Local high exposures in interventional radiology (IR) and nuclear medicine (NM) are due to the closeness of medical staff to the direct and scattered field, in the first case, and to the direct handling of radionuclides, in the second.

Many studies in IR have shown that the doses can vary a lot, even for the same type of procedure. The routine monitoring of the extremities (hands, forearms and legs) is difficult to be performed thus only data for whole body, fingers and wrists are reported.

Moreover, eye lens dose is rarely estimated, even if there is some evidence that cataract is an increasing effect in exposed population. In NM the main topic is the skin dose, but is generally unknown which part of the hand receives highest doses and which is the dose distribution in the hand itself. Indeed, the use of unsealed sources with high


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Session 8: Radiation protection of workers – Oral presentationsFerrari, Paolo et al.Challenges on the radiation protection optimization of medical staff in interventional radiology and nuclear…

activities and beta emitters in therapeutic NM can worsen the situation for the involved personnel.

These aspects are studied within the ORAMED (Optimization of RAdiation protection of MEDical staff) project, funded by EU-EURATOM FP7, studies in which a series of European laboratories and hospitals participate. The project is subdivided in 5 work packages: extremity and eye lens dosimetry in IR and cardiology (WP1); development of practical eye lens dosimetry in IR (WP2); optimisation of the use of active personal dosemeters in IR (WP3); extremity dosimetry in NM (WP4); and training and dissemination (WP5). In the present work the state of the art of the main tasks performed in WP1, WP2 and WP4 is briefly summarized.

Introduction The ORAMED project, funded through the FP7, was set up to optimize radiation protection in Interventional Radiology and Cardiology (IR/IC) and Nuclear Medicine (NM) focusing the attention to the dose to the extremities and eye-lens.

The published studies on the doses to the medical staff [Donadille et al. 2008, Ginjaume et al. 2008, Kim and Miller 2009, Martin 2009, Vanhavere et al. 2008, Vano et al. 2008, Zorzetto et al. 1997] report a large variability of the estimated values due to the patient scattering, the followed procedure (for the IR/IC), the kind of radionuclide (for NM), the skill of the operators and the radiation protection devices used (for both) and all of them underline the need of a radiation protection optimization. Moreover, regarding eye lens doses, there is some evidence that cataracts can be produced at lower doses level [Junk et al 2008] and the ICRP itself [ICRP 2008] is moving to this direction.

In IR/IC procedures the medical staff is likely to receive significant radiation doses to their hands and parts of their body not covered with protective equipment (as legs and forearms) because physicians are close to X-ray field. In NM practices the dose to the hands is the main issue, especially when unsealed sources are used. About eye-lens the recent evidences of cataracts at lower doses pointed out the lack of an optimized dose assessment for such organs. Hp(3) is seldom used in the routine radiation protection practice: when required, it is usually deduced from Hp(0.07) and Hp(10) evaluation.

The ORAMED project (http://www.oramed-fp7.eu) started in the beginning of 2008 and will run for 3 years. Within the project a coordinated measurement program in selected European hospitals is presently on-going. The measurement campaign is accompanied by a series of numerical simulations of the most representative workplaces/procedures to determine the main parameters that influence the extremity and eye lens doses. The project is structured in 5 work packages (WPs) all devoted to investigate the medical staff doses in IR/IC and NM. In WP2 Hp(3) operational quantity has been investigated and a suitable dosemeter responding in terms of Hp(3) has been produced. In the present paper the state of the art of WP1 (extremity and eye lens dosimetry in IR/IC), WP2 and WP4 (extremity dosimetry in NM) is summarized.


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Material and methods

WP1- Extremity and eye lens dosimetry in IR/IC The objective of WP1 is to obtain a set of standardized data on doses for staff in interventional radiology and cardiology with the aim of optimizing medical staff radiation protection. The coordinated measurement program in some selected major European hospitals, established in the first year of the project, is still in progress. The procedures to be followed were chosen on basis of a retrospective study from hospital data on the frequency of procedures and the respective KAP (kerma air product) values. The final list includes 3 cardiac procedures- cardiac angiographies (CA) and angioplasties (PTCA), radiofrequency ablations (RFA), pacemaker implantations (PM) - and 5 general interventional diagnostic and therapeutic examinations - angiographies (DSA) and angioplasties (PTA) of the lower limbs (LL), of the carotids (C) and renal (R), embolisations and endoscopic retrograde cholangiopancreatographies (ERCP).

The measurements have been performed according to a protocol supplied to each hospital allowing the homogenization of the collected data. Parameters such as the KAP values, the radiation protection equipment used by the staff and the staff position during the practice have been noted down in order to correlate them with the evaluated doses.

TL dosemeters (LiF:Mg,Cu,P) were used for the measurements. Eight TLDs were sealed in small plastic bags and taped on the parts of the body to be monitored: 2 for the ring fingers, 2 for the wrists, 2 for the unshielded part of the legs (about 5 cm below the lead apron) 1 between the eyes and 1 near the left/right eye, depending if the tube is on the left/right side of the doctor respectively. The measurements during preliminary tests showed that these positions are the most exposed. A previous intercomparison exercise, in which TLDs were irradiated to 137Cs and X-ray beams on the ISO slab phantom, assured that all partners could evaluate comparable doses in terms of Hp(0.07).

Due to the complexity of establishing the main parameters influencing the doses in IR/IC, it was decided to perform a numerical analysis using anthropomorphic models with MCNPX Monte Carlo transport code [Pelowitz 2005]. A first simulation intercomparison was performed in order to work on a common basis for the numerical campaign. The input simulates a typical irradiation scenario: the anthropomorphic MIRD-ORNL [Snyder et al. 2008] model was modified extracting arms from the body structure and arranging forearms and hands in a way that is more similar to that expected for the cardiologist during the insertion of the catheter. A second model, representing the patient, is laying in front the physician that stands at the patient’s femur. Eyes, a thyroid collar, a lead apron of 0.5 mm thickness and the Image Intensifier tube have been added in order to better simulate the real situation (Figure 1). A simulation protocol has been established after a preliminary test that demonstrated the need for variance reduction techniques - MCNPX DXTRAN spheres [Briesmeister 2000]- especially for the small tallies (hands and eyes).

Since the number of the simulations that was finally agreed was too high it was decided to perform the whole analysis (called sensitivity analysis) on three simplified phantoms, a cylinder, (for IR practice in the head) and two phantoms representing the thorax and the whip (for the different IR/IC procedures of those anatomical regions) and to adopt detailed models only to check some parameters (as shielding) or for particular tests.


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Fig. 1. The modified ORNL-MIRD type models employed in the IR/IC simulation.

WP2- Eye lens dosimetry and Hp(3) dosemeter development The objective of WP2 is to investigate the theoretical framework within which the operational quantity Hp(3) is defined and the posibility to develop a dosemeter responding in terms of the operational quantity itself.

Until now Hp(3) conversion coefficients were not reported in the official recommendations and the only available data were calculated by GSF (now Helmoltz Institute) for a 30 x 30 x 15 cm3 4 element ICRU tissue-equivalent slab phantom [Till et al 1995]. The operational quantity should be defined in a phantom able to reproduce the interaction and scattering properties of the part of the body considered. This is the reason why the 4 element ICRU tissue-equivalent slab phantom (representing the thorax) is not well suited to represent the human head. For instance, a preliminary study allowed to investigate if Hp(3) could be defined in a cylindrical phantom of 20 cm diameter and 20 cm height. The shape and the dimensions of this model were defined on the basis of the morphology of the head of the ORNL-MIRD anthropomorphic phantom, which was created according to the characteristics of the standard man expressed by ICRP 23 [ICRP 1975] and ICRP 89 [ICRP 2003]. The calculated Hp(3)/KAIR for slab and cylindrical phantoms, for monoenergetic photons and different angles were compared to the reference ICRP limiting quantity eye-lens equivalent dose HT(eye-lens) [ICRU 1998].

A cylindrical PMMA calibration phantom, with the same dimensions of the theoretical model, filled with water, was developed for the following dosemeter type-testing (Figure 2). A series of MCNP simulations was performed in order to determine the backscatter properties of the proposed model [Mariotti and Gualdrini 2009]. Mono-energetic and ISO narrow beam spectrum series at different incident angles and distances from the phantom lateral surface were considered. The Monte Carlo simulations were validated through a series of measurements of the kerma in air with and without the corresponding plastic phantom using a small volume ionization chamber. The characterized calibration phantom was used in the rest of the work.

Starting from these studies the dosemeter development was planned. A series of Monte Carlo simulations was employed to determine which of the available plastic materials was more suitable for the expected 3 mm soft tissue attenuation related to the Hp(3) definition. The chosen material was used to provide the encapsulation of the TL


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MCP-N (LiF:Mg,Cu,P) chip. The study of the complete dosemeter (TL + plastic encapsulation) response with respect to the imparted Hp(3)/KAIR was carried out through a series of Monte Carlo simulations at various incident angles. The developed prototype is being tested at CEA laboratories at 137Cs and standard RQR X-ray beams on the cylindrical phantom. The characterized dosemeters will be used in the selected hospitals in order to evaluate the eye-lens doses for IR/IC procedures.

Fig. 2. The cylindrical calibration phantom for eye-lens operational quantity dosemeter testing.

WP4- Extremity dosimetry in NM The objective of WP4 is to evaluate extremity doses and dose distributions across the hands of the medical staff working in nuclear medicine departments. To achieve this, an extensive measurement and simulation program has been started.

A measuring working plan was established following a defined protocol: the labelling and administration of radiopharmaceuticals for diagnostics (99mTc and 18F) and therapy procedures (Zevalin and DOTATOC labelled with 90Y ) were taken into account (other radionuclides as 32P, 177Lu or 153Sm were also considered). The procedures were selected according to their frequency in the collaborative hospitals.

To measure the skin dose across the hands, special gloves were designed with high sensitivity thermoluminescent dosemeters (TLD) specific to beta and gamma radiation placed at a minimum of 11 different positions on each hand (Figure 3). The TLDs inserted in the plastic envelops could reproduce adequately the quantity Hp(0.07). For each procedure a minimum number of measurements was required. Each procedure had to be performed by two operators and in two hospitals assuring an adequate evaluation of the intrinsic variability in the expected doses.

An initial comparison of the different TLDs used by the WP4 participants was performed with 137Cs and 85Kr sources in order to establish a common basis for the measurement campaign in the different nuclear medicine departments.

In order to check the different parameters contributing to the dose and to the dose reduction to the operators (position with respect source, adopted shieldings etc..), it was decided to perform a series of numerical simulations (called sensitivity analysis) reproducing the most common scenarios encountered during the measurements. 2 different scenarios for injecting and 3 different ones for labelling have been selected: handling of a syringe, handling of a vial directly with or without forceps. Hand


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phantoms made of paraffin have been produced by SMU and scanned using a CT. Voxel models of the phantoms were created by IRSN and employed as input for the sensitivity analysis (Figure 4). The numerical models were validated through a series of measurements done using the paraffin phantom in laboratory in controllable conditions. The sensitivity analysis is ongoing.

Fig. 3. The operator’s gloves equipped with dosemeters for the dosimetric study in WP4.

Fig. 4. The paraffin hand used in validation and its voxel model representation.

Results The measurements and simulation campaigns are in progress; therefore the presented results are only preliminary. Here only few examples of the analysis are reported, a complete investigation of the outcomes will be presented at the final ORAMED workshop.

WP1 For the measurements part, up to now 797 interventional procedures (377 cardiac, 277 general angiographies and 143 Endoscopic Retrograde CholangioPancreatographies, ERCP) in 33 European hospitals have been performed.

The measured KAP values vary from 0.46 Gycm2, recorded in PM procedure, to 942 Gycm2 in embolisation. Generally high KAP values are encountered when large number of images/frames is acquired. The KAP values present high distribution even within the same type of procedure, which shows the complexity of the procedure, the variability in the techniques and the influence of the skill of the physicians. The median doses for general angiography procedures are usually higher than for cardiac and ERCP and the left side of the operator is the more exposed to the scattered radiation from the patient (Figure 5).


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Fig. 5. Mean Hp(0.07) values in mSv for cardiac, genaral angiography and ERCP procedures.

The maximum dose that was recorded was at the left finger in a CA and PTCA procedure (2.08 mSv, KAP=380 Gycm2). The maximum eye dose (1.28 mSv) was recorded in the embolisation with the highest KAP value.

For CA and PTCA procedures, the fingers received slightly higher dose than the wrists, and the legs higher than the eyes. For the RFA procedures, the finger and wrist doses are higher than the leg and the eye ones as in the CA and PTCA procedures.

For the PM interventions the Hp(0.07) values are generally low due to the short fluoroscopy time and the absence of image acquisitions, although values up to 0.4 mSv/procedure were recorded in the finger region. In those cases the hands were very close or sometimes even inside the beam. In PM implantations the operator’s position can be closer to the patient compared to the other interventional procedures so it is not easy to use the protective equipment of the table and ceiling.

In DSA, PTA of lower limbs and carotids the finger and wrist doses are higher than the leg ones. In the embolisations, the wrist doses are higher than the fingers which are in agreement with Whitby and Martin [2005]. Finally the doses recorded in the ERCP interventions are small varying from 0 to 0.03 mSv.

About the sensitivity analysis the tube voltage was changed from 60 to 110 kVp and filtration from 3 to 6 mm Al and from 0 to 0.9 mm Cu. Calculations were performed for different beam projections: PA, LAO and RAO (30°, 60°, 90°), caudal and cranial (20° and 40°) combinations of them. A total of 3300 calculations for the simplified study and at least 220 detailed ones were performed. For all projections, the results showed that doses received by the operator decreased with increasing tube voltage and filtration. When the slab phantom was used the maximum doses for all tallies were observed for the LAO90 beam projection and the minimum ones for the RAO30. In the case of the cylindrical head phantom the maximum doses for all tallies were observed for the CRAN40 beam projection and the minimum ones for the RAO90 and RAO30. As expect the increasing beam aperture increases also the doses in particular for the wrists and the hands, for example, for the slab phantom the doses to the hands and wrists are reduced more than 3 times when the field size changes from 40 to 20 cm in diameter. The effects of the tube voltage and of the filtrations on the doses depend strongly on the irradiated part of the body and the beam projection.


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WP2 The simulations demonstrated the validity of the performed analysis on Hp(3) definition. In figure 6, Hp(3)/KAIR calculated for monoenergetic photons employing the cylindrical model and the 30 30 13 cm3 4-element ICRU tissue-equivalent material are compared with the HT(eye-lens)/KAIR. As it can be seen the operational quantity defined in the cylindrical phantom is able to reproduce better the ICRP limiting quantity; a complete analysis can be found in an ENEA report [Mariotti and Gualdrini 2009]. The conversion coefficients for Hp(3) were calculated in Kerma approximation, assuming the energy of the secondary charged particles deposited locally. A parallel investigation considering the electron transport was performed by CEA, using the Penelope code [Salvat et al. 2006] and demonstrated, as expected, the overestimation of the conversion coefficients calculated in the kerma approximation at 3 mm depth in soft tissue for energies above 1 MeV [Daures et al. 2009].

The dosemeter development was based on a series of Monte Carlo simulations. In Figure 7 the response of the complete (capsule + TL chip) RADCARDTM dosemeter, normalized per imparted Hp(3), are presented at normal incidence angle for monoenergetic photons for different encapsulation material.

WP4 At the moment, 635 measurements coming from 32 nuclear medicine departments across Europe have been introduced in the database. Results are from diagnostic and therapeutic procedures and include both phases: preparation and injection.

To compare measurements from different departments, measured doses were normalized to the manipulated activity. A large spread of results, due to the influence of many factors, such as the type of protections used and the experience of the technicians is observed. The complete statistical analysis of the results is under progress.

From the 11 measuring points across the hand, it has been observed that the most exposed positions are the tip of the index finger and the thumb, usually of the non dominant hand.

The data analysis is ongoing, the preliminary comparison showed that for 99mTc administration the maximum dose is 1.5 (mSv/GBq) at index tip. This is the lowest registered maximum dose being 3.7 (mSv/GBq) and 11.2 (mSv/GBq) the evaluated maximum index tip doses for the 18F and 90Y respectively. These values change for the labeling case: 2.0 (mSv/GBq) for 99mTc 4.4 (mSv/GBq) 18F and 32.0 (mSv/GBq) for 90Y.

Usually labelling delivers higher doses than the administration of the radiopharmaceutical because the activities manipulated for labelling are higher than those manipulated for the administration of the radiopharmaceutical and some of the labelling steps are performed with an unshielded source whilst the administration is usually performed with a shielded syringe.

The impact of placing the routine monitoring dosemeter at a different position than the one corresponding to the maximal hand dose has been estimated by computing dose ratios between the position corresponding to the maximum in the hand (usually the index tip) and the position normally used for routine monitoring (usually the base of the index or the ring finger). The calculated ratios vary from 1 to 7 depending on the radionuclide and the procedure.


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About the simulations the established protocol has the scope of evaluating changes in extremity doses varying different parameters. The outcome of these calculations will be used to define practical guidelines. To verify the consistency between measurements and simulations, several measurements were done in laboratory conditions: in Figure 8 18F injection with unshielded syringe measurements on paraffin hand are compared with the same data obtained with the computational voxel model. The agreement between the data is satisfactory. The sensitivity analysis is in progress.

Fig. 6. Hp(3)/KAIR in slab (GSF) and cylindrical (proposed model) phantoms compared with HTeye-lens for normal incident monoenergetic photon beams.

Fig. 7. Study of the response of the RADCARD dosemeter prototype - R/Hp(3) at normal incidence: comparison between PMMA, PU and SLA capsules.


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Fig. 8. Validation of the numerical simualtion: comparison between the results obtained with measurements in laboratory and the simualtion of FDG injection with unshielded syringe.

Conclusions The ORAMED project aims at developing methodologies for better assessing and reducing exposures to medical staff. In the present paper the activities related to the working groups 1,2 and 4 have been summarized.

WP-1 - Measurement and calculation of extremity and eye lens doses in interventional radiology and cardiology: a set of standardized data on doses for staff in interventional radiology and cardiology have been collected. A series of recommended radiation protection measures to optimize staff protection will be prepared on the basis of the outcomes of the wide numerical simulation campaign that is ongoing.

WP-2 - Development of practical eye lens dosimetry in interventional radiology: the operational quantity has been investigated, producing a new set of conversion coefficients for Hp(3)/KAIR, a new calibration phantom was adopted and the first prototype of the dosemeter, responding in terms of Hp(3), was developed. The dosemters will be supplied to IR/IC medical staff of a selected number of hospitals in order to assess eye-lens doses for radiation protection optimization.

WP-4 – the optimization of the extremity dosimetry of medical staff in nuclear medicine: a set of doses across the hand for administration and labelling of radiopharmaceuticals have been registered for a selected number of European hospitals. The data allowed to study the maximum dose and to determine the relationship between that maximum and the dose registered in the usual position where the routine dosemeter are worn. The simulations are still in progress, and they will be used to determine the effect of parameters influencing the radiation protection in those medical practices.

ORAMED project final workshop ORAMED, Optimization of RAdiation protection for MEDical staff is a collaborative project funded in 2008 within the 7th EU Framework Programme, Euratom Programme for Nuclear Research and training. The final International Workshop of Optimization of Radiation Protection of Medical Staff will be held in Barcelona, 20–22 January 2011. The research leading to these results has received funding from the European Atomic Energy Community's Seventh Framework Programme (FP7/2007-2011) under grant agreement n° 211361.


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References Briesmeister J F (editor) MCNP - A General Monte Carlo N-Particle Transport Code,

Version 4C Los Alamos National Laboratory Report LA-13709-M Manual 2000 Daures J, Gouriou J, Bordy J M Conversion coefficients from air kerma to personal

dose equivalent Hp(3) for eye-lens dosimetry 2009 CEA-R-6235 Donadille L, Carinou E, Ginjaume M, Jankowski J, Rimpler A, Sans Merce M and

Vanhavere F An overview of the use of extremity dosemeters in some European countries Radiat. Prot. Dosim. 2008; 131: 62–66.

Ginjaume M, Carinou E, Donadille L, Jankowski J, Rimpler A, Sans Merce M, Vanhavere F, Denoziere M, Daures J, Bordy J M, Itie C and Covens P. Extremity ring dosimetry intercomparison in reference and workplace fields. Radiat. Prot. Dosim. 2008; 131: 67-72.

International Commission on Radiological Protection Report of the Task group on Reference Man ICRP Publication 23. Pergamon; 1975.

International Commission on Radiological Protection Basic Anatomical and Physiological Data for Use in Radiological Protection:Reference Values. ICRP Publication 89. Pergamon; 2003.

International Commission on Radiological Units and Measurements Conversion coefficients for use in radiological protection against external radiation Report 57 Bethesda 1998

International Commission on Radiological Protection. 2007 recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Oxford; Pergamon Press; 2008.

Junk A E , Kyrychenko O Y, Musijachenko N V et al. Risk of Cataract after Exposure to Low Doses of Ionizing Radiation: A 20-Year Prospective Cohort Study among US Radiologic Technologists American Journal of Epidemiology 2008 168(6): 620-631

Kim K P and Miller D Minimising radiation exposure to physicians performing fluoroscopically guided cardiac catheterisation procedures: a review 2009 Radiat. Prot. Dosim. 133(4): 227-233

Lie O O, Paulsen G U, Wohni T Assessment of effective dose and dose to the lens of the eye for the interventional cardiologist Radiat. Prot. Dosim. 2008; 132(3): 313-318

Mariotti F, Gualdrini G, ORAMED project. Eye-Lens Dosimetry. A new Monte Carlo approach to define the operational quantity Hp(3), ENEA Technical Report ISSN/0393-3016, RT/2009/1/BAS 2009.

Martin J C A review of radiology staff doses and dose monitoring requirements Radiat. Prot. Dosim. 2009; 136(3): 140-157

Pelowitz D B (editor), MCNPX User's manual. LA-CP-05-0369, Los Alamos Laboratoty, USA 2005

Salvat F, Fernandez-Varea J.M. Sempau J PENELOPE-2006. A Code System for Monte Carlo. Simulation of Electron and Photon Transport, 2006 OECD/NEA

Snyder W S, Ford M R and Warner G G Estimates of absorbed fraction for monoenergetic photon sources uniformly distributed in various organs and heterogeneous model. Report ORNL-4979 Oak Ridge National Laboratory, Oak Ridge, TN, USA. 1978


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Till E, Zankl M, Drexler G Angular dependence of depth doses in a tissue slab irradiated with monoenergetic photons. Neuherberg, Germany: GSF-bericht 27/95: 1995.

Vanhavere F, Carinou E, Donadille L, Ginjaume M, Jankowski J, Rimpler A, Sans Merce M An overview of extremity dosimetry in medical applications. Radiat. Prot. Dosim. 2008; 129: 350-355.

Vano E, Gonzalez L, Fernandez J M, Haskal Z J Eye Lens Exposure to Radiation in Interventional Suites: Caution Is Warranted Radiology 2008; 248(3): 945 - 953.

Whitby M and Martin C J A study of the distribution of dose across the hands of interventional radiologists and cardiologists. Br J Radiol 2005; 78: 219-229

Zorzetto M, Bernardi G, MorocuttiG, Fontanelli A Radiation exposure to patients and operators during diagnostic catheterization and coronary angioplasty Catheterization and Cardiovascular Diagnosis; 1997 40(4): 348-352


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Increased extremity doses for staff in the preparation and administration of beta-emitters and PET nuclides in nuclear medicine

Linder, Reto; Stritt, Nicolas Swiss Federal Office of Public Health, Radioprotection Division, SWITZERLAND

Abstract Due to the continuous increase in extremity doses in nuclear medicine departments, the Swiss Federal Office of Public Health (SFOPH), in its capacity as the supervisory and regulatory authority dealing with ionising radiation, has investigated the reasons for this and introduced measures aimed at their reduction. Since the mid-90s, the SFOPH has observed a continuous increase in extremity doses of persons occupationally exposed to radiation in nuclear medicine departments. Whereas only a few persons in the 50 facilities had accumulated an extremity dose greater than 25mSv/year in 1996, ten years later there were almost 10 times more. This development was all the more worrying because it is assumed that the extremity dosimeters used actually record only a fraction of the extremity dose effectively accumulated, especially when dealing with beta-emitters. In facilities with high patient throughput and frequent therapeutic uses, it is therefore possible that the dose limit (500mSv/y) is occasionally exceeded. The SFOPH looked into this radiation protection problem and since 2006 has undertaken audits in the relevant nuclear medicine departments to determine the reasons for the increased extremity doses, to optimise doses as far as possible and to order corresponding actions. It was established that there is considerable optimisation potential not only in the preparation of radiopharmaceuticals but also in their application, such that a marked reduction of extremity doses is possible. However, this partly depends on investment in systems, which automate dose-intensive manipulations, such as the loading and activity determination of injection syringes or even the injection into patients. When staff are aware that even a brief manipulation with unscreened therapeutic doses could result in high extremity doses, they generally use the shielding aids more conscientiously and adopt work plans and procedures that optimise radiation protection.

Introduction The Swiss Federal Office of Public Health (SFOPH) is responsible for enforcing the radiological protection legislation [1] in Switzerland. In its role as the supervisory and licensing authority in radiological protection, the SFOPH monitors the radiation doses of persons occupationally exposed to radiation, of patients and the general population. Over the last 10 years the SFOPH has observed a continuous increase in extremity


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Session 8: Radiation protection of workers – Oral presentationsLinder, Reto and Stritt, NicolasIncreased extremity doses for staff in the preparation and administration of beta-emitters and PET nuclides in…

doses for persons occupationally exposed to radiation in the approximately 50 Swiss nuclear medicine departments monitored. Fig. 1 shows the trend in extremity doses (greater than 25 mSv and greater then 50 mSv per year) between 1989 and 2006. Four years ago this led the SFOPH to focus on this topic in order to determine the causes and to initiate possible measures for the reduction of doses.

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Fig. 1. Trend of extremity doses in nuclear medical facilities from 1989 – 2006.

The main raison for this trend is the growing use of new radiopharmaceutical products for therapeutic use (see Fig. 2) and the increase of departments that carry out PET examinations. Ten years ago there were 5 PET units in operation, nowadays there are already more than 20. Consequently, the use of F-18 has also correspondingly increased.

In a first step all the services concerned were audited in order to determine the current radiation protection practice and in which areas the radiation protection could be further improved. The findings from these audits are intended to be used in a second step to elaborate and publish recommendations for radiation protection and training programmes for the personnel concerned.


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Fig. 2. Use of beta emitters for therapeutic purposes 1996-2008.

Material and methods Nuclear medicine departments to be audited were selected on the basis of the use of F-18 and beta emitters (Y-90, Lu-177, Re-186, Sm-153, etc.). Data for increased extremity doses (greater than 10mSv/year) were consulted as a further criterion using the Swiss Central Dose Register. A total of 30 departments that handle beta emitters and/or PET nuclides were identified. The remaining 20 nuclear medical institutes work predominantly with Tc-99m, where increased extremity doses are rarely observed. In the audit, the personnel who are responsible for the organisation and monitoring of the radiation protection in the facility were interviewed. In addition, specialist staff (physicians, radiographers, chemists, laboratory technicians), who carry out preparation work in the isotope laboratory and administer radiopharmaceuticals to patients, were consulted as needed. In the planning of the questions for the audit, emphasis was placed on the 4 following topics:

1 Organisation of Radioprotection Monitoring of radiation doses by means of external dosimetry (extremity dosimeters and whole body dosimeters) is an important instrument for reviewing working procedures. However, this is only valid if the dosimeters are worn consistently and in the right position. Investigations in a service with a high volume of Y-90 have shown that the highest doses are accumulated on the left palm of the hand (for right handed individuals). These results were also confirmed in a study [3] carried out under contract for the SFOPH (Fig. 3) by the Lausanne University Institute of Applied Radiation Physics (IRA).


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little finger ring finger middle finger index fingerthumb

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Fig. 3 Doses to fingers of the hands in the course of a preparation of a Zevalin® application (right handed individual).

The radiation protection expert in each service has the task of quickly clarifying increased or even regular doses, and to demonstrate how they can be avoided or reduced. If unusually high extremity doses are recorded in a department, then the persons in question must be quickly notified in order to clarify how this could have occurred. An important aspect is also the organisation of the distribution of the radiation doses. In this regard, unavoidable dose-intensive work should be distributed among as many staff as possible. Having said that, it must also be ensured, that the staff have adequate working routines so as to quickly and safely carry out these procedures.

2 Radiation protection training and continuous professional development Persons occupationally exposed to radiation must have the relevant technical knowledge and competence, i.e. must at least be aware of radiation protection rules and dose-optimised work practices. In order to maintain this technical knowledge, the person who is responsible for radiation protection in the department must regularly organise continuing training for themselves and their colleagues. Prior to introducing new applications, all working steps with radioactive substances have to be planned and practiced from the viewpoint of reduced dose work techniques. Personnel who mainly work with conventional radionuclides (Tc-99m) used in nuclear medicine must be instructed that when manipulating beta emitters and F-18 there is an increased risk of accumulating high hand doses.

3 Equipment Isotope laboratories used for the preparation of radiopharmaceuticals and administration rooms must be equipped in such a way that radiation sources are shielded as much as possible in order to reduce the dose to the personnel. Suitable containers must be available for the storage of radiopharmaceuticals and radioactive waste ([4] Ordinance for the use of unsealed radioactive substances). When manipulating radiation sources, short distances and easy access must enable fast and safe work.


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4 Aids and auxiliaries for radiation protection When using beta emitters, suitable Plexiglas shielding must be present and consistently employed (Fig. 4 and 5). When using F-18 for PET diagnostics, thick-walled lead or tungsten shielding has to be used in order to reduce the dose rates (Fig. 6). Vials containing radioactive substances or syringes, into which a radiopharmaceutical is aspirated, must be consistently shielded when manipulated. Manipulations lasting a few seconds without shielding can lead to doses of several mSv to the hand. Direct contact with unshielded syringes and vials should be avoided at all costs; indeed, should the situation arise, then remote handling devices such as gripping arms and tweezers should be employed. Because even small splashes can cause considerable skin doses, it is vital to wear gloves for all manipulations. As according to [2] latex gloves provide only inadequate protection from contamination, vinyl or nitrile gloves should be worn when handling beta emitters with high specific activity. With high patient turnover and extensive nuclide use, increased extremity doses can generally only be avoided if suitable automatic dispensers are utilised for filling syringes and administering the radiopharmaceuticals.

Fig. 4. Vial Plexiglas shielding Fig. 5. Syringe shielding for Fig. 6. Lead shielding for F-18. for beta emitters. beta emitters.

Results The radiation protection audits in the nuclear medicine departments generally aroused a high interest and were considered to be useful. The persons responsible for radiation protection and their colleagues are well aware that repeated use of beta emitters and PET nuclides leads to increased accumulated doses and especially extremity doses. Moreover, specific measurements of hand doses on the fingertips have demonstrated that the doses recorded by ring dosimeters, especially when working with beta emitters, do not reflect the maximum accumulated radiation doses. It can be assumed that the effective maximum hand doses are higher by a factor of 3 to 5. When comparing the monthly accumulated radiation doses with the therapies carried out, it could be further established that high values often correlate with individual beta therapies. An analysis and review of the radiation protection situation in the various departments yielded primarily the following two findings:


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1 Organisation, training and continuous education Audits in the different services have shown that the personnel and the responsible persons are well aware of the problem of increased extremity doses. However, training in this field must be further improved. The working procedures are partially configured from experience of handling conventional nuclides such as Tc-99m and the work places are correspondingly designed. There is a lack of awareness that unshielded beta emitters, even when manipulated for a few seconds, can already induce extremity doses of several mSv. Contrary to widespread belief, the time factor plays a minor role compared with shielding (a 10mm Plexiglas shielding reduces the dose rates by a factor of 1000). Discipline in regard to wearing extremity dosimeters is generally good. It is not universally known on which part of the hand the highest doses are to be expected, and hence where the dosimeters should be worn. The “radiation protection culture” in the services is generally well understood but can still be improved. Repeated high doses for staff are partially taken for granted and consistent optimisation is not sought after. In contrast, dose-intensive work is generally distributed as well as possible among the available staff, taking into consideration adequate training and procedures.

2 Facilities and resources In nuclear medicine services where beta emitters are only used occasionnally, the work places are often not set up in such a way as to enable the handling of radioactivity over the shortest possible distances. Moreover, ready-for-use radiopharmaceuticals are often directly syringed out of the suppliers’ shielded containers, which do not ensure adequate shielding above the top. Generally, remote handling devices such as tongs and tweezers are mainly employed when handling vials and syringes (Fig. 7). However, the temptation to intervene directly with ones hands for tricky work is great and often occurs even without thinking. Attaching and removing needle tips and three-way stopcocks (Fig. 8) is often carried out by hand. Even with attached shielding, needle tips are insufficiently shielded. Although there are some devices for this, their use is mostly felt as too laborious.

Fig. 7. Tweezers with Plexiglas beta shielding. Fig. 8 Attaching the tip to a 3-way stopcock.

Prior to the administration of the radiopharmaceutical to the patient, the charged activity in the syringe has to be measured and verified in an activimeter [4]. As the


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syringe for this has to be removed from the shielding and this procedure is often carried out several times for an accurate dosage, this manipulation is dose-intensive. For this reason particular care must be taken to ensure that the arrangement of the workspace and the location of the activimeter allows fast working. If the activimeter is suitably calibrated, then the measurement of the activity of F-18 can also be carried out with the shielding in place. In some facilities syringes can also be filled automatically. However, practice-proven systems are expensive and also require a lot of space. For this reason devices of this type are primarily installed in services where the purchase and installation can be financially justified by a high patient turnover. Recently however, simpler, cheaper systems have also become available on the market. Nevertheless they still have to be proven in practice before they can find widespread use. A facility that has high turnovers of Y-90 and Lu-177 and consequently also carries out costly labelling, employs radiation protective gloves for some manipulations. Measurements have demonstrated that with these lead gloves - which are also used in interventional X-ray diagnostics - the hand doses can be reduced by a factor of 3 to 4. The methods of administration, depending on the application, are often very different in various institutes even within the same application. This presents a considerable potential for optimisation in this work procedure. If long-term administrations are also carried out in some hospitals with manual injections, they are carried out elsewhere automatically with syringe perfusions. A newly developed PET infusion system, developed in one of the services, actually allows a fully automatic dosing and injection. Following the audit of the SFOPH, binding measures for optimising radiation protection were agreed with the responsible persons. In addition to organisational aspects, such as intensifying the internal training and continuous education or verifying regularly how dosimeters are worn, these measures also include in-depth investigations by the service for the potential optimisation of specific dose-intensive work procedures and appropriate possibilities for assessment are submitted to the supervisory authority.

Discussion With the SFOPH conducting audits, awareness about increased extremity doses was raised. Accordingly, tangible improvements were successfully introduced in the majority of facilities. The success of these efforts is also shown by the fact that between 2007, when the audits began, and 2009 the extremity doses in nuclear medical services have decreased by 23% (annual doses greater than 25 mSv) and 31% (annual doses greater than 50 mSv). An evaluation of whether individual working procedures can be optimised regarding radiation protection of the extremities, can however not be exhaustively made during an audit. For this reason it is intended to make a detailed examination of the operational procedures in various services, as has also been recommended in a statement by the Federal Commission on Radiological Protection and Monitoring of Radioactivity (CRP) to the SFOPH [6]. In order to detect and record possible errors and their effects, the maximum finger doses should be measured with TLDs on the finger tips during critical manipulations (Fig. 9). The work procedures could also be filmed in order to subsequently analyse the causes of the accumulated doses. Automated dosing and injection systems offer a high capability for reducing the hand doses. Experiments in a PET Centre with a fully automatic doser/injector have shown that a dose reduction by a factor of greater than 10 is possible [5].


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However, proven systems are rare and expensive and are only available in institutes that have high numbers of patients and corresponding financial means. More cost efficient systems have still to be tested in depth and must provide evidence that the quality of the dosing or the injection is at least as good as in a manual procedure.

Fig. 9. TLD for the determination of the maximum dose to extremities.

Conclusions Developments in nuclear medicine show that applications involving PET nuclides and beta emitters will probably increase further. For this reason, additional measures must be provided for the training and continuing education of the staff in order to avoid any further increase in extremity doses. The SFOPH will therefore produce and publish a continuing education DVD, which will illustrate optimised radiation work procedures when handling beta emitters and PET nuclides. Furthermore, a recommendation for radiation protection is intended to be drawn up for this topic and practical continuing education courses will be offered. In addition, the question of whether automatic systems should be made mandatory for dose-intensive work procedures will be examined.

References [1] Strahlenschutzgesetz vom 22. März 1991 (StSG) SR 814.50, Strahlen-

schutzverordnung vom 22. Juni 1994 (StSV) SR 814.501 [2] Rimpler A. Radiation protection of the personnel in radioimmunotherapy with Y-

90. BfS aktuell, p.4, vol. 8 (2005) [3] Dosimétrie des extrémités, Rapport intermédiaire Mandat OFSP. Institut

universitaire de radiophysique appliquée, Lausanne (2006) [4] Verordnung vom 21. November 1997 über den Umgang mit offenen radioaktiven

Strahlenquellen (VUOS) SR 814 554 [5] Thomas Berthold, Michael Belohlavy, Sabrina Lauper, Mirjam De Bloeme,

Bruno Weber und Alfred Buck. Drastische Reduktion der Hand-Strahlenbelastung von MTAs bei vollautomatischer Injektion von 18F-FDG (2004)

[6] KSR Stellungnahme zuhanden des BAG betreffend die Extremitätendosimetrie in der Nuklearmedizin (2009)


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Morphological dependence of lung counting efficiency for female workers

Farah, Jad; Broggio, David; Franck, Didier Institut de Radioprotection et de Sûreté Nucléaire, IRSN/DRPH/SDI/LEDI, BP-17 F-92262 Fontenay-aux-Roses Cedex, FRANCE

Abstract In vivo lung monitoring of female workers is routinely performed using calibration coefficients calculated with a male thoracic mannequin since no female model exists. More appropriate calibration coefficients can be obtained using numerical models. In this work, flexible 3D Mesh and NURBS (Non Uniform Rational B-Splines) geometries were considered to design representative female thorax. Lung counting efficiencies were simulated for typical germanium detectors and the parameters of their morphological dependence were defined.

A library of 24 different 3D female models was created representing the most common female breasts with various cup sizes (A to F) and chest girths (85 to 120). Monte Carlo simulations were then achieved to investigate the chest girth and cup size effects on the counting efficiency. It was shown that for the 59.54 keV Am-241 gamma ray, the counting efficiency decreases of about 15% between the 85A and the 85B phantoms. Moreover, a 55 fold decrease in efficiency was observed at 22 keV between the 120C and the 85C phantoms.

An equation was developed, involving simple physical assumptions, which defines any counting efficiency as a function of chest girth, cup size and a reference efficiency curve. Morphology-dependent parameters were calculated in order to estimate the efficiency curve of any female subject (any breast size and morphology) if a reference efficiency is provided. Furthermore, the developed equation was able to describe the relation between the calculated female efficiency and the Livermore calibration data. It was found that the simulated 85A efficiency curve is in close agreement with the calibration measurements performed with the Livermore and its first extra-thoracic plate. Since this agreement depends notably on the chosen counting position for females, it was also shown how to transform calibration measurements performed with other thoracic plates.

This work enables a better assessment of the in vivo calibration coefficients improving the female workers monitoring.


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Session 8: Radiation protection of workers – Oral presentationsFarah, Jad et al.Morphological dependence of lung counting efficiency for female workers

Introduction After an intake of radionuclides, in vivo counting and bioassays are the only two available techniques enabling the assessment of the retained activity (ICRP 1988). To correctly estimate the contamination using in vivo spectrometry, counting systems accurate calibration is required. The latter is typically done using anthropomorphic physical phantoms (ICRU 2003). However, there is no female torso phantom even though the female morphology can significantly influence the count. Hence, Monte Carlo (MC) calculations and numerical models of the human body are used to obtain realistic calibration factors, compensating for the absence or poor realism of physical phantoms (de Carlan et al. 2007, Hunt et al. 1998, Kramer et al. 2009)

The first numerical models (mathematical phantoms) represented the human complex anatomy by simple equations. Later, the voxelized phantoms were introduced in radiation protection to offer a more realistic representation than the mathematical phantoms (Zankl et al. 1988) and the ICRP has recently released reference male and female voxel models (ICRP 2009). Recent developments in 3D formats and associated tools enabled the design of more flexible anthropomorphic 3D models. Indeed, Mesh or NURBS formats can be easily manipulated and transformed to obtain various representative postures or morphologies (Xu et al. 2007, Lee et al. 2007).

Here we address the question of the morphological dependence of counting efficiency curves for in vivo lung monitoring of female workers. For this purpose a library of 24 female torsos, representing the most common breast sizes and morphologies, was designed using Mesh and NURBS formats. MC calculations of the counting efficiencies of a typical Germanium counting system were achieved for all phantoms. Next, a simple analytic formula was derived to describe the morphology effect on counting efficiency. Finally, a practical example is given to show how an experimental reference calibration curve, obtained with the Livermore phantom, can be transformed to provide efficiency corrections for most common breast morphologies.

Material and methods This work first presents the Monte Carlo calculations carried out with the designed phantoms. Then, it focuses on the parameterization of the morphological dependency of the counting efficiency. The definition of an analytic formula is given to describe the relation between efficiency curves obtained for each female phantom. This equation is validated using Monte Carlo simulated data and tested with experimental efficiencies obtained with the Livermore phantom. 1. Simulation of in vivo lung counting measurements A flexible female library of 24 torso models, representing most common breast morphologies, was created starting from the ICRP Adult Female Reference Computational Phantom (ICRP AF-RCP) (ICRP 2009). When creating the female thoracic 3D models, breast cup size variation was achieved by adipose tissue adding according to plastic surgery recommendations (Turner and Dujon 2005). Realistic variation of

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