Committee 3 of the International Commission on Radiological Protection (ICRP) develops recommendations and guidance for protection of patients, staff, and the public against radiation exposure when ionising radiation is used for medical diagnosis, therapy, or biomedical research. This paper presents a summary of the work that Committee 3 has accomplished over the past few years, and also describes its current work. The most recent reports published by the Commission that relate to radiological protection in medicine are ‘Radiological protection in cone beam computed tomography’ (Publication 129), ‘Radiation dose to patients from radiopharmaceuticals: a compendium of current information related to frequently used substances’ (Publication 128, in cooperation with Committee 2), ‘Radiological protection in ion beam radiotherapy’ (Publication 127), ‘Radiological protection in paediatric diagnostic and interventional radiology’ (Publication 121), ‘Radiological protection in cardiology’ (Publication 120), and ‘Radiological protection in fluoroscopically guided procedures outside the imaging department’ (Publication 117). A new report on diagnostic reference levels in medical imaging will provide specific advice for interventional radiology, digital imaging, computed tomography, nuclear medicine, paediatrics, and hybrid (multi-modality) imaging procedures, and is expected to be published in 2016. Committee 3 is also working on guidance for occupational radiological protection in brachytherapy, and on guidance on occupational protection issues in interventional procedures, paying particular attention to the 2011 Commission’s recommendations on the occupational dose limit for the lens of the eye (Publication 118). Other reports in preparation deal with justification, radiological protection in therapy with radiopharmaceuticals, radiological protection in medicine as related to individual radiosusceptibility, appropriate use of effective dose (in cooperation with other Committees), and guidance for healthcare practitioners on radiological and patient protection. Committee 3 has also suggested specific priorities for research on radiological protection in medicine to the Commission.
1. MANDATE OF COMMITTEE 3 ‘PROTECTION IN MEDICINE’
Committee 3 of the International Commission on Radiological Protection (ICRP) develops recommendations and guidance for protection of patients, staff, and the public against radiation exposure when ionising radiation is used for medical diagnosis, therapy, or biomedical research.
For the 2013–2017 term, Committee 3 is composed of 16 members with expertise in different areas of radiological protection in medicine: medical physics; nuclear medicine; radiology (including several subspecialties within radiology); and radiation oncology. They are: Eliseo Vañó (Chair); Donald Miller (Vice Chair); Madan Rehani (Secretary); Katrine Åhlström-Riklund; Kimberly Applegate; Michel Bourguignon; Lawrence Dauer; Sandor Demeter; Keon Kang; Pek-Lan Khong; Reinhard Loose; Pedro Ortiz López; Colin Martin; Pierre Scalliet; Yoshiharu Yonekura; and Baorong Yue.
The membership of Committee 3 demonstrates a wide geographical distribution. Members are from 12 different countries (http://www.icrp.org/icrp_group.asp?id=9). Committee 3 currently has two emeritus members, Sören Mattsson and Marvin Rosenstein, who contribute actively to the ongoing reports. A public summary of the annual meetings is available on the ICRP website (http://www.icrp.org/icrp_group.asp?id=9).
ICRP maintains formal relations with other organisations with an interest in radiological protection through specific agreements, or by granting special liaison status to organisations whose work is relevant to the ICRP mandate. Representatives from the World Health Organization (WHO) (María Pérez) and from the International Atomic Energy Agency (IAEA) (Ola Holmberg) attend the annual meetings of Committee 3.
International organisations and stakeholders are encouraged to propose topics of interest for new reports. In addition, a new mechanism, introduced at the second ICRP symposium, provides opportunities for symposium participants to provide input on suggested topics to the Commission’s Committees. The members of each Committee review the proposals relevant to their Committee's area of responsibility, and evaluate the need to produce reports on specific topics. Each Committee forwards its recommendations to the Commission of ICRP. The work suggested by the Committees is subject to approval by the Commission.
This paper presents a summary of the work that Committee 3 has accomplished over the past few years, and also describes its current work.
2. THE MOST RECENT REPORTS
The reports led by Committee 3 over the last 5 y are as follows.
Publication 113. Education and training in radiological protection for diagnostic and interventional procedures. Approved by the Commission in October 2010 but dated 2009 for editorial reasons (ICRP, 2009). The need for education and training of medical staff (including medical students) and other healthcare professionals in the principles of radiological protection is more compelling today than in the past. This report expands previous basic ICRP recommendations with regard to various categories of medical practitioners and other healthcare professionals who perform, provide support for, or refer patients for diagnostic and interventional procedures that utilise ionising radiation, or nuclear medicine therapy. It provides guidance regarding the necessary radiological protection education and training for use by: (a) regulators, health authorities, medical institutions, and professional bodies with responsibility for radiological protection in medicine; (b) the industry that produces and markets the equipment used in these procedures; and (c) universities and other academic institutions responsible for the education of professionals involved in the use of ionising radiation in health care. Advice is also provided on the accreditation and certification of the recommended education and training. In the context of this report, the term ‘accreditation’ means that an organisation has been approved by an authorised body to provide education or training on the radiological protection aspects. The term ‘certification’ means that an individual medical or clinical professional has successfully completed the education or training provided by an accredited organisation.
Publication 117. Radiological protection in fluoroscopically guided procedures performed outside the imaging department. Approved by the Commission in October 2011, but dated 2010 for editorial reasons (ICRP, 2010). An increasing number of medical specialists use fluoroscopy outside imaging departments, but there has been a general neglect of radiological protection coverage of fluoroscopy used outside imaging departments. Lack of radiological protection training of those working with fluoroscopy outside imaging departments can increase radiation risk to workers and patients. Procedures such as endovascular aneurysm repair, renal angioplasty, iliac angioplasty, ureteric stent placement, therapeutic endoscopic retrograde cholangiopancreatography, and bile duct stenting and drainage have the potential to impart skin doses exceeding 1 Gy. Although tissue reactions among patients and workers from fluoroscopy procedures have, to date, only been reported in interventional radiology and cardiology, the volume of fluoroscopy use outside imaging departments creates potential for such injuries. Specific aspects of protection are included for vascular surgery, urology, orthopaedic surgery, obstetrics and gynaecology, gastroenterology and the hepatobiliary system, and anaesthesia and pain management. Information on radiation dose levels to patients and workers, and recommendations for dose management are presented for each speciality. Radiological protection for pregnant patients and pregnant workers is also covered. Specific needs for the target groups in terms of orientation of training, competency of those who conduct and assess specialists, and guidelines on the curriculum are also provided. The report emphasises that patient dose monitoring is essential whenever fluoroscopy is used.
Publication 120. Radiological protection in cardiology. Approved by the Commission in October 2011, but dated 2013 for editorial reasons (ICRP, 2013a). Cardiac nuclear medicine, cardiac computed tomography (CT), interventional cardiology procedures, and electrophysiology procedures are increasing in number and account for an important share of patient radiation exposure in medicine. Complex percutaneous coronary interventions and cardiac electrophysiology procedures are associated with high radiation doses. These procedures can result in patient skin doses that are high enough to cause radiation injury and increased risk of cancer. Treatment of congenital heart disease in children is of particular concern. Additionally, staff in cardiac catheterisation laboratories may receive high doses of radiation if radiological protection tools are not used properly. This report provides guidance to assist the cardiologist with justification of procedures and optimisation of protection in cardiac CT studies, cardiac nuclear medicine studies, and fluoroscopically guided cardiac interventions. It includes discussions of the biological effects of radiation, principles of radiological protection, protection of staff during fluoroscopically guided interventions, radiological protection training, and establishment of a quality assurance programme for cardiac imaging and intervention. As tissue injury, principally skin injury, is a risk for fluoroscopically guided interventions, particular attention is devoted to clinical examples of radiation-related skin injuries from cardiac interventions, methods to reduce patient radiation dose, training recommendations, and quality assurance programmes for interventional fluoroscopy.
Publication 121. Radiological protection in paediatric diagnostic and interventional radiology. Approved by the Commission in October 2011, but dated 2013 for editorial reasons (ICRP, 2013b). Paediatric patients have a higher average risk of developing cancer than adults who receive the same radiation dose. The longer life expectancy in children allows more time for any harmful effects of radiation to manifest, and some developing organs and tissues are more sensitive to the effects of radiation. This report aims to provide guiding principles of radiological protection for referring clinicians and clinical staff performing diagnostic imaging and interventional procedures for paediatric patients. It begins with a brief description of the basic concepts of radiological protection, followed by the general aspects of radiological protection, including principles of justification and optimisation. Guidelines and suggestions for radiological protection in specific modalities – radiography and fluoroscopy, interventional radiology, and CT – are subsequently covered in depth. The report concludes with a summary and recommendations. The importance of rigorous justification of radiological procedures is emphasised for every procedure involving ionising radiation, and the use of imaging modalities that are non-ionising should always be considered. Special consideration should be given to the availability of dose reduction measures when purchasing new imaging equipment for paediatric use. Major paediatric interventional procedures should be performed by experienced paediatric interventional operators, and a second, specific level of training in radiological protection is desirable for these individuals (in some countries, this is mandatory). For CT, dose reduction should be optimised by adjusting scan parameters according to the patient’s weight or age. This report will assist institutions in encouraging the standardisation of procedures, and may help to increase awareness and ultimately improve practices for the benefit of patients.
Publication 127. Radiological protection in ion beam radiotherapy. Approved by the Commission in October 2014 (ICRP, 2014). The goal of external beam radiotherapy is to provide precise dose localisation in the treatment volume of the target with minimal damage to the surrounding normal tissue. Ion beams, such as protons and carbon ions, provide excellent dose distributions due primarily to their finite range, allowing a significant reduction of undesired exposure of normal tissue. Careful treatment planning is required for the given type and localisation of the tumour to be treated in order to maximise treatment efficiency and minimise the dose to normal tissue. Radiation exposure in ‘out of field’ volumes arises from secondary neutrons and photons, particle fragments, and photons from activated materials. These unavoidable doses should be considered from the standpoint of radiological protection of the patient. Radiological protection of medical staff at ion beam radiotherapy facilities requires special attention. Appropriate management and control are required for the therapeutic equipment and the air in the treatment room that can be activated by the particle beam. Ion beam radiotherapy requires a more complex treatment system than conventional radiotherapy, and appropriate training of staff and suitable quality assurance programmes are recommended to avoid possible accidental exposure of patients, to minimise unnecessary doses to normal tissue, and to minimise radiation exposure of staff.
Publication 128 (in cooperation with Committee 2). Radiation dose to patients from radiopharmaceuticals: a compendium of current information related to frequently used substances. Approved by the Commission in July 2014 (ICRP, 2015a). This report is a compilation and ‘transition’ report to facilitate the work of users of ICRP reports on radiopharmaceuticals until the new dose coefficients for the International Commission on Radiation Units and Measurements (ICRU)/ICRP reference computational phantoms for adults and children of various ages become available. The report compiles current ICRP information relating to radiation dose to patients, including biokinetic models, biokinetic data, dose coefficients for organ and tissue absorbed doses, and effective dose for major radiopharmaceuticals based on the radiological protection guidance given in previous ICRP reports. This report also includes new information for 82Rb-chloride, iodide (123I, 124I, 125I, and 131I) and 123I-labelled 2ß-carbomethoxy 3ß-(4-iodophenyl)-N-(3-fluoropropyl) nortropane. The data presented in this report are intended for diagnostic nuclear medicine and not for therapeutic applications. The report also includes annexes on special biokinetic and dosimetric models, and recommendations on breast-feeding interruptions.
Publication 129. Radiological protection in cone beam computed tomography. Approved by the Commission in January 2015 (ICRP, 2015b). The objective of this report is to provide guidance on radiological protection in the new technology of cone beam computed tomography (CBCT). The new applications of CBCT and the associated radiological protection issues are substantially different from those of conventional CT. The perception that CBCT involves lower doses was only true in initial applications. CBCT is now used widely by specialists who have little or no training in radiological protection. This report provides recommendations on radiation dose management directed at different stakeholders, and covers principles of radiological protection, training, and quality assurance aspects. Advice on appropriate use of CBCT needs to be made widely available. Advice on optimisation of protection when using CBCT equipment needs to be strengthened, particularly with respect to the use of newer features of the equipment. Manufacturers should standardise radiation dose displays on CBCT equipment to assist users in optimisation of protection and comparisons of performance. Additional challenges to radiological protection are introduced when CBCT-capable equipment is used for both fluoroscopy and CBCT during the same procedure. Standardised methods need to be established for tracking and reporting of patient radiation doses from these procedures.
3. WORK IN PROGRESS
Committee 3 is currently working on the following reports.
Task Group 89. Occupational radiological protection in brachytherapy (Chair: L. Dauer) Task Group 89 is developing a report related specifically to radiological protection of staff in brachytherapy. Publications 97, 98 and 105 (ICRP, 2005a,b, 2007) have addressed radiological protection principles for patients, but there is a need for relevant and practical recommendations for radiological protection of staff in brachytherapy. The target audience is clinicians, staff, medical physicists, radiological protection officers, and regulatory authorities. It is expected that this report will assist in partially implementing several of the IAEA Bonn call-for-action.
Task Group 36. Radiation dose to patients from radiopharmaceuticals [Chairs: D. Nosske (Committee 2) and S. Mattsson (Committee 3 emeritus)] This is a standing Task Group of Committees 3 and 2. Task Group 36 has prepared a one-volume compendium published as Publication 128 (ICRP, 2015a) on radiation dose to patients from radiopharmaceuticals. It includes data compiled mainly from previous ICRP reports, with new information for several radionuclides. Work with the models for certain radiopharmaceuticals is ongoing, including biokinetic models for 11C-PIB Compound B and 11C-choline. There is also an analysis of published data on the results of ongoing clinical studies for the Alzheimer markers 18F-Flutemetamol and 18F-Florbetapir, for which the development of biokinetic models is planned.
Task Group 101. Radiological protection in therapy with radiopharmaceuticals [Chair: Y. Yonekura. Honory Co-Chair: S. Mattsson (Committee 3 emeritus)] Radionuclide therapy is used increasingly for the treatment of various types of tumours by introduction of novel radionuclides, compounds, tracer molecules, and application techniques. The objective is to explore a framework for dosimetry and radiological protection aspects in these novel treatment approaches, and to identify those situations with unique aspects that should be considered. It is expected to include aspects of individual dosimetry and radiobiology of α emitters.
Working Party on diagnostic reference levels in medical imaging (Chair: E. Vañó) This report was posted on the ICRP website for public consultation in January 2016. Previous recommendations have been taken into account (ICRP, 2001a). Appropriate contact with the Consortium preparing the European guidelines on paediatric diagnostic reference levels (DRLs) has been maintained to avoid discrepancies between the two reports. The report contains chapters on methods for surveys to establish DRLs; radiography and diagnostic fluoroscopy; interventional procedures; digital radiography, CT, nuclear medicine, and hybrid (multi-modality) imaging procedures; paediatrics; and application of DRLs in clinical practice. The report contains main points at the beginning of each chapter, and concludes with a summary of the Commission’s recommendations.
Working Party on occupational protection issues in interventional fluoroscopically-guided and CT-guided procedures (Chair: P. Ortiz López) The preliminary draft includes chapters on trends in the use of interventional procedures, an overview of exposures and reported tissue reactions, application of the principles of radiological protection to occupational exposures in interventions, staff protection, dose constraints and investigation levels for occupational protection (body, eye, and hands), protection of pregnant workers, exposure monitoring, protective methods and devices, and the hospital radiological protection programme. A first complete draft of the whole document was analysed during the 2015 annual meeting of Committee 3.
Working Party on justification (general issues) (Chair: K. Åhlström-Riklund) Several organisations have produced, or are preparing, documents in the same field. The ICRP justification report is expected to have content not published elsewhere, and not to be a repetition of material already published on issues related to justification.
Working Party on radiological protection in medicine related to individual radiosusceptibility (in cooperation with Committee 1) (Chair: M. Bourguignon) The Working Party discussed clarification of the concepts of radiosensitivity and radioesthesia. Radiosensitivity is expressed at high doses as early and late tissue reactions after radiotherapy that occur without any error in the delivery of the therapeutic dose. It is due to cell death and tissue responses. Radioesthesia is expressed at low doses as the development of stochastic effects (cancer) after: (a) multiple medical imaging examinations that result in a cumulative dose; or (b) after radiotherapy, in areas of normal tissue that receive scatter from the treatment beam. It is a result of survival of cells with altered DNA due to genetic disorders or instabilities that contribute to the alteration of the DNA damage response. It is considered that: (a) many tests are available in research laboratories to evaluate both radiosensitivity and radioesthesia; and (b) the two concepts should be addressed in subgroups of the populations concerned. The issue of ethics for medical exposures should also be addressed. Genetic mapping in medicine for individualised treatment is pending. An initial draft document was discussed during the annual meeting of Committee 3 in Seoul in October 2015.
Working Party on radiation and patient protection: a guide for healthcare practitioners (Chair: S. Demeter) This is an update of the ICRP web-based educational document entitled ‘Radiation and your patient: a guide for medical practitioners’ (2001b) (free access: http://www.icrp.org/docs/Rad_for_GP_for_web.pdf). Substantial material on radiological protection already exists, published by reputable organisations such as WHO, IAEA, and the National Council on Radiation Protection and Measurements, the goal is to create concise short educational pieces that highlight and reflect what ICRP contributes to the issue. A final draft will be discussed at the October 2015 annual meeting of Committee 3.
4. OTHER ACTIVITIES
Educational slides. Several collections of educational slides corresponding to the most recent reports of Committee 3 have been completed and are available for free download (http://www.icrp.org/page.asp?id=35). These educational slide sets are for:
‐ Publication 113 (Education and training in radiological protection);
‐ Publication 117 (Fluoroscopically guided procedures);
‐ Publication 120 (Radiological protection in cardiology); and
‐ Publication 121 (Radiological protection in paediatrics).
Future topics under consideration. During the annual meetings of Committee 3, proposals for new topics to be considered by the Committee as future work are discussed. The list of topics under consideration contains the following items:
‐ framework for optimisation for individual patients;
‐ dose quantities and units for imaging equipment (in cooperation with ICRU); and
‐ patient eye dose in CT in light of the new threshold for the lens of the eye (ICRP, 2012).
Suggestions on research priorities. Topics considered as priorities for research are also discussed by Committee 3 during its annual meetings. The most recent topics suggested to the Commission are:
‐ approaches to improve protection methods and occupational dose assessment in interventional fluoroscopy and nuclear medicine procedures;
‐ patient dosimetry and protection in high-dose procedures (interventional and CT);
‐ dosimetric data to help in the assessment of cardiovascular, pulmonary fibrosis, and cerebrovascular effects in radiotherapy and high-dose imaging procedures;
‐ development and validation of newer methods to improve image quality while reducing patient doses, including criteria for acceptable levels of image quality for clinical CT and digital imaging;
‐ patient risk assessment and risk communication; and
‐ x-ray energy at 30 kV vs 120 kV for mammography vs CT (suggested to Committee 1).
