IAEA/WHO postal dosimetry audit methodology for electron beams using radio photoluminescent dosimeters.

BACKGROUND: Independent dosimetry audits are an important intervention in radiotherapy for quality assurance. Electron beams, used for superficial radiotherapy treatments, must also be tested in dosimetry audits as part of a good quality assurance program to help prevent clinical errors. PURPOSE: To establish a new service for IAEA/WHO postal dosimetry audits in electron beams using RPL dosimeters. METHODS: A novel postal audit methodology employing a PMMA holder system for RPLDs was developed. The associated correction factors including holder dependence, energy dependence, dose response non-linearity, and fading were obtained and tested in a multi-center (n = 12) pilot study. A measurement uncertainty budget was estimated and employed in analyzing the irradiated dosimeters. RESULTS: Holder and energy correction factors ranged from 1.004 to 1.010 and 1.019 to 1.059 respectively across the energy range. The non-linearity and fading correction models used for photon beams were tested in electron beams and did not significantly increase measurement uncertainty. The mean dose ratio ± SD of the multi-center study was 1.001 ± 0.011. The overall uncertainty budget was estimated as ± 1.42% (k = 1). CONCLUSIONS: A methodology for IAEA/WHO postal dosimetry audits in electron beams was developed and validated in a multi-center study and is now made available to radiotherapy centers as a routine service.

Global Radiotherapy: Current Status and Future Directions-White Paper.

Recognizing the increase in cancer incidence globally and the need for effective cancer control interventions, several organizations, professional bodies, and international institutions have proposed strategies to improve treatment options and reduce mortality along with minimizing overall incidence. Despite these efforts, an estimated 9.6 million deaths in 2018 was attributed to this noncommunicable disease, making it the second leading cause of death worldwide. Left unchecked, this will further increase in scale, with an estimated 29.5 million new cases and 16.3 million deaths occurring worldwide in 2040. Although it is known and generally accepted that cancer services must include radiotherapy, such access is still very limited in many parts of the world, especially in low- and middle-income countries. After thorough review of the current status of radiotherapy including programs worldwide, as well as achievements and challenges at the global level, the International Atomic Energy Agency convened an international group of experts representing various radiation oncology societies to take a closer look into the current status of radiotherapy and provide a road map for future directions in this field. It was concluded that the plethora of global and regional initiatives would benefit further from the existence of a central framework, including an easily accessible repository through which better coordination can be done. Supporting this framework, a practical inventory of competencies needs to be made available on a global level emphasizing the knowledge, skills, and behavior required for a safe, sustainable, and professional practice for various settings. This white paper presents the current status of global radiotherapy and future directions for the community. It forms the basis for an action plan to be developed with professional societies worldwide.

Dosimetry of small static fields used in external photon beam radiotherapy: Summary of TRS-483, the IAEA-AAPM international Code of Practice for reference and relative dose determination.

PURPOSE: A joint IAEA/AAPM international working group has developed a Code of Practice (CoP) for the dosimetry of small static fields used in external megavoltage photon beam radiotherapy, published by the IAEA as TRS-483. This summary paper introduces and outlines the main aspects of the CoP. METHODS: IAEA TRS-483 is a condensation of the wide range of different approaches that have been described in the literature for the reference dosimetry of radiotherapy machines with nominal accelerating potential up to 10 MV that cannot establish the conventional 10 cm × 10 cm reference field, and for the determination of field output factors for relative dosimetry in small static photon fields. The formalism used is based on that developed by Alfonso et al. [Med Phys. 2008;35:5179-5186] for this modality. RESULTS: Three introductory sections describe the rationale and context of the CoP, the clinical use of small photon fields, and the physics of small-field dosimetry. In the fourth section, definitions of terms that are specific to the CoP (as compared to previous CoPs for broad-beam reference dosimetry, such as IAEA TRS-398 and AAPM TG-51) are given; this section includes a list of the symbols and equivalences between IAEA and AAPM nomenclature to facilitate the practical implementation of the CoP by end users of IAEA TRS-398 and AAPM TG-51. The fifth section summarizes the equations and procedures that are recommended in the CoP and the sixth section provides an overview of the methods used to derive the data provided in IAEA TRS-483. CONCLUSIONS: This is the first time an international Code of Practice for the dosimetry of small photon fields based on comprehensive data and correction factors has been published. This joint IAEA/AAPM CoP will ensure consistent reference dosimetry traceable to the international System of Units and enable common and internationally harmonized procedures to be followed by radiotherapy centers worldwide for the dosimetry of small static megavoltage photon fields.

Nuclear and radiological emergencies: Building capacity in medical physics to support response.

Medical physicists represent a valuable asset at the disposal of a structured and planned response to nuclear or radiological emergencies (NREs), especially in the hospital environment. The recognition of this fact led the International Atomic Energy Agency (IAEA) and the International Organization for Medical Physics (IOMP) to start a fruitful collaboration aiming to improve education and training of medical physicists so that they may support response efforts in case of NREs. Existing shortcomings in specific technical areas were identified through international consultations supported by the IAEA and led to the development of a project aiming at preparing a specific and standardized training package for medical physicists in support to NREs. The Project was funded through extra-budgetary contribution from Japan within the IAEA Nuclear Safety Action Plan. This paper presents the work accomplished through that project and describes the current steps and future direction for enabling medical physicists to better support response to NREs.

Assessment of cancer control capacity and readiness: the role of the International Atomic Energy Agency.

During the past six decades, the International Atomic Energy Agency (IAEA) has helped to address the growing cancer burden, by delivering substantial cancer-related assistance to low-income and middle-income member states. IAEA assistance has primarily been facilitated through sustainable radiotherapy and nuclear medicine programmes to establish safe and effective diagnostic imaging, nuclear medicine, and radiotherapy capacity to safely treat patients with cancer. Planning of a National Cancer Control Programme starts with a needs assessment of all aspects of cancer control in the country to ensure evidence-based strategies are adapted to the country's specific needs. The IAEA offers its member states a tool, known as an integrated mission of Programme of Action for Cancer Therapy Review, to assess the status of national capacities for implementation and delivery of cancer control plans and activities and the readiness to develop and implement a long-term radiation medicine infrastructure and plan to improve capacity.

Improving Quality and Access to Radiation Therapy-An IAEA Perspective.

The International Atomic Energy Agency (IAEA) has been involved in radiation therapy since soon after its creation in 1957. In response to the demands of Member States, the IAEA׳s activities relating to radiation therapy have focused on supporting low- and middle-income countries to set up radiation therapy facilities, expand the scope of treatments, or gradually transition to new technologies. In addition, the IAEA has been very active in providing internationally harmonized guidelines on clinical, dosimetry, medical physics, and safety aspects of radiation therapy. IAEA clinical research has provided evidence for treatment improvement as well as highly effective resource-sparing interventions. In the process, training of researchers occurs through this program. To provide this support, the IAEA works with its Member States and multiple partners worldwide through several mechanisms. In this article, we review the main activities conducted by the IAEA in support to radiation therapy. IAEA support has been crucial for achieving tangible results in many low- and middle-income countries. However, long-term sustainability of projects can present a challenge, especially when considering health budget constraints and the brain drain of skilled professionals. The need for support remains, with more than 90% of patients in low-income countries lacking access to radiotherapy. Thus, the IAEA is expected to continue its support and strengthen quality radiation therapy treatment of patients with cancer.

Radiation Oncology Quality and Safety Considerations in Low-Resource Settings: A Medical Physics Perspective.

The past few years have seen a significant growth of interest in the global radiation therapy (RT) crisis. Various organizations have quantified the need and are providing aid in support of addressing the shortfalls existing in many low-to-middle income countries. With the tremendous demand for new facilities, equipment, and personnel, it is very important to recognize the quality and safety challenges and to address them directly. An examination of publications on quality and safety in RT indicates a consistency in a number of the recommendations; however, these authoritative reports were generally based on input from high-resourced contexts. Here, we review these recommendations with a special emphasis on issues that are significant in low-to-middle income countries. Although multidimensional, training, and staffing are top priorities, any support provided to lower-resourced settings must address the numerous facets associated with quality and safety indicators. Strong partnerships between high income and other countries will enhance the development of safe and resource-appropriate strategies for advancing the radiation treatment process. The real challenge is the engagement of a strong spirit of cooperation, collaboration, and communication among the multiple organizations in support of reducing the cancer divide and improving the provision of safe and effective RT.

Accuracy requirements and uncertainties in radiotherapy: a report of the International Atomic Energy Agency.

BACKGROUND: Radiotherapy technology continues to advance and the expectation of improved outcomes requires greater accuracy in various radiotherapy steps. Different factors affect the overall accuracy of dose delivery. Institutional comprehensive quality assurance (QA) programs should ensure that uncertainties are maintained at acceptable levels. The International Atomic Energy Agency has recently developed a report summarizing the accuracy achievable and the suggested action levels, for each step in the radiotherapy process. Overview of the report: The report seeks to promote awareness and encourage quantification of uncertainties in order to promote safer and more effective patient treatments. The radiotherapy process and the radiobiological and clinical frameworks that define the need for accuracy are depicted. Factors that influence uncertainty are described for a range of techniques, technologies and systems. Methodologies for determining and combining uncertainties are presented, and strategies for reducing uncertainties through QA programs are suggested. The role of quality audits in providing international benchmarking of achievable accuracy and realistic action levels is also discussed. RECOMMENDATIONS: The report concludes with nine general recommendations: (1) Radiotherapy should be applied as accurately as reasonably achievable, technical and biological factors being taken into account. (2) For consistency in prescribing, reporting and recording, recommendations of the International Commission on Radiation Units and Measurements should be implemented. (3) Each institution should determine uncertainties for their treatment procedures. Sample data are tabulated for typical clinical scenarios with estimates of the levels of accuracy that are practically achievable and suggested action levels. (4) Independent dosimetry audits should be performed regularly. (5) Comprehensive quality assurance programs should be in place. (6) Professional staff should be appropriately educated and adequate staffing levels should be maintained. (7) For reporting purposes, uncertainties should be presented. (8) Manufacturers should provide training on all equipment. (9) Research should aid in improving the accuracy of radiotherapy. Some example research projects are suggested.

Detector to detector corrections: a comprehensive experimental study of detector specific correction factors for beam output measurements for small radiotherapy beams.

PURPOSE: The aim of the present study is to provide a comprehensive set of detector specific correction factors for beam output measurements for small beams, for a wide range of real time and passive detectors. The detector specific correction factors determined in this study may be potentially useful as a reference data set for small beam dosimetry measurements. METHODS: Dose response of passive and real time detectors was investigated for small field sizes shaped with a micromultileaf collimator ranging from 0.6 × 0.6 cm(2) to 4.2 × 4.2 cm(2) and the measurements were extended to larger fields of up to 10 × 10 cm(2). Measurements were performed at 5 cm depth, in a 6 MV photon beam. Detectors used included alanine, thermoluminescent dosimeters (TLDs), stereotactic diode, electron diode, photon diode, radiophotoluminescent dosimeters (RPLDs), radioluminescence detector based on carbon-doped aluminium oxide (Al2O3:C), organic plastic scintillators, diamond detectors, liquid filled ion chamber, and a range of small volume air filled ionization chambers (volumes ranging from 0.002 cm(3) to 0.3 cm(3)). All detector measurements were corrected for volume averaging effect and compared with dose ratios determined from alanine to derive a detector correction factors that account for beam perturbation related to nonwater equivalence of the detector materials. RESULTS: For the detectors used in this study, volume averaging corrections ranged from unity for the smallest detectors such as the diodes, 1.148 for the 0.14 cm(3) air filled ionization chamber and were as high as 1.924 for the 0.3 cm(3) ionization chamber. After applying volume averaging corrections, the detector readings were consistent among themselves and with alanine measurements for several small detectors but they differed for larger detectors, in particular for some small ionization chambers with volumes larger than 0.1 cm(3). CONCLUSIONS: The results demonstrate how important it is for the appropriate corrections to be applied to give consistent and accurate measurements for a range of detectors in small beam geometry. The results further demonstrate that depending on the choice of detectors, there is a potential for large errors when effects such as volume averaging, perturbation and differences in material properties of detectors are not taken into account. As the commissioning of small fields for clinical treatment has to rely on accurate dose measurements, the authors recommend the use of detectors that require relatively little correction, such as unshielded diodes, diamond detectors or microchambers, and solid state detectors such as alanine, TLD, Al2O3:C, or scintillators.

IAEA support to medical physics in nuclear medicine.

Through its programmatic efforts and its publications, the International Atomic Energy Agency (IAEA) has helped define the role and responsibilities of the nuclear medicine physicist in the practice of nuclear medicine. This paper describes the initiatives that the IAEA has undertaken to support medical physics in nuclear medicine. In 1984, the IAEA provided guidance on how to ensure that the equipment used for detecting, imaging, and quantifying radioactivity is functioning properly (Technical Document [TECDOC]-137, "Quality Control of Nuclear Medicine Instruments"). An updated version of IAEA-TECDOC-137 was issued in 1991 as IAEA-TECDOC-602, and this included new chapters on scanner-computer systems and single-photon emission computed tomography systems. Nuclear medicine physics was introduced as a part of a project on radiation imaging and radioactivity measurements in the 2002-2003 IAEA biennium program in Dosimetry and Medical Radiation Physics. Ten years later, IAEA activities in this field have expanded to cover quality assurance (QA) and quality control (QC) of nuclear medicine equipment, education and clinical training, professional recognition of the role of medical physicists in nuclear medicine physics, and finally, the coordination of research and development activities in internal dosimetry. As a result of these activities, the IAEA has received numerous requests to support the development and implementation of QA or QC programs for radioactivity measurements in nuclear medicine in many Member States. During the last 5 years, support was provided to 20 Member States through the IAEA's technical cooperation programme. The IAEA has also supported education and clinical training of medical physicists. This type of support has been essential for the development and expansion of the Medical Physics profession, especially in low- and middle-income countries. The need for basic as well as specialized clinical training in medical physics was identified as a priority for healthcare providers in many countries. The IAEA's response to meet the increasing needs for training has been 2-folds. Through its regular program, a priority is given to the development of standardized syllabi and education and clinical training guides. Through its technical cooperation programme, support is given for setting up national medical physics education and clinical training programs in countries. In addition, fellowships are granted for professionals working in the field for specialized training, and workshops are organized at the national and regional level in specialized topics of nuclear medicine physics. So as to support on-the-job training, the IAEA has also setup a gamma camera laboratory in Seibersdorf, Austria. The laboratory is also equipped with QC tools and equipments, and radioisotopes are procured when training events are held. About 2-3 specialized courses are held every year for medical physicists at the IAEA gamma camera laboratory. In the area of research and development, the IAEA supports, through its coordinated research projects, new initiatives in quantitative nuclear medicine and internal dosimetry. The future of nuclear medicine is driven by advances in instrumentation, by the ever increasing availability of computing power and data storage, and by the development of new radiopharmaceuticals for molecular imaging and therapy. Future developments in nuclear medicine are partially driven by, and will influence, nuclear medicine physics and medical physics. To summarize, the IAEA has established a number of programs to support nuclear medicine physics and will continue to do so through its coordinated research activities, education and training in clinical medical physics, and through programs and meetings to promote standardization and harmonization of QA or QC procedures for imaging and treatment of patients.

Safety in radiation oncology: the role of international initiatives by the International Atomic Energy Agency.

The International Atomic Energy Agency (IAEA) has a wide range of initiatives that address the issue of safety. Quality assurance initiatives and comprehensive audits of radiotherapy services, such as the Quality Assurance Team for Radiation Oncology, are available through the IAEA. Furthermore, the experience of the IAEA in thermoluminescence dosimetric audits has been transferred to the national level in various countries and has contributed to improvements in the quality and safety of radiotherapy. The IAEA is also involved in the development of a safety reporting and analysis system (Safety in Radiation Oncology). In addition, IAEA publications describe and analyze factors contributing to safety-related incidents around the world. The lack of sufficient trained, qualified staff members is addressed through IAEA programs. Initiatives include national, regional, and interregional technical cooperation projects, educational workshops, and fellowship training for radiation oncology professionals, as well as technical assistance in developing and initiating local radiation therapy, safety education, and training programs. The agency is also active in developing staffing guidelines and encourages advanced planning at a national level, aided by information collection systems such as the Directory of Radiotherapy Centers and technical cooperation project personnel planning, to prevent shortages of staff. The IAEA also promotes the safe procurement of equipment for radiation therapy centers within a comprehensive technical cooperation program that includes clinical, medical physics, and radiation safety aspects and review of local infrastructure (room layout, shielding, utilities, and radiation safety), the availability of qualified staff members (radiation oncologists, medical physicists, and radiation technologists and therapists), as well as relevant imaging, treatment planning, dosimetry, and quality control items. The IAEA has taken the lead in developing a comprehensive program that addresses all of these areas of concern and is actively contributing to the national and international efforts to make radiation therapy safer in all settings, including resource-limited settings.

International Conference on Advances in Radiation Oncology (ICARO): outcomes of an IAEA meeting.

The IAEA held the International Conference on Advances in Radiation Oncology (ICARO) in Vienna on 27-29 April 2009. The Conference dealt with the issues and requirements posed by the transition from conventional radiotherapy to advanced modern technologies, including staffing, training, treatment planning and delivery, quality assurance (QA) and the optimal use of available resources. The current role of advanced technologies (defined as 3-dimensional and/or image guided treatment with photons or particles) in current clinical practice and future scenarios were discussed.ICARO was organized by the IAEA at the request of the Member States and co-sponsored and supported by other international organizations to assess advances in technologies in radiation oncology in the face of economic challenges that most countries confront. Participants submitted research contributions, which were reviewed by a scientific committee and presented via 46 lectures and 103 posters. There were 327 participants from 70 Member States as well as participants from industry and government. The ICARO meeting provided an independent forum for the interaction of participants from developed and developing countries on current and developing issues related to radiation oncology.

Dosimetry in diagnostic radiology.

Dosimetry is an area of increasing importance in diagnostic radiology. There is a realisation amongst health professionals that the radiation dose received by patients from modern X-ray examinations and procedures can be at a level of significance for the induction of cancer across a population, and in some unfortunate instances, in the acute damage to particular body organs such as skin and eyes. The formulation and measurement procedures for diagnostic radiology dosimetry have recently been standardised through an international code of practice which describes the methodologies necessary to address the diverging imaging modalities used in diagnostic radiology. Common to all dosimetry methodologies is the measurement of the air kerma from the X-ray device under defined conditions. To ensure the accuracy of the dosimetric determination, such measurements need to be made with appropriate instrumentation that has a calibration that is traceable to a standards laboratory. Dosimetric methods are used in radiology departments for a variety of purposes including the determination of patient dose levels to allow examinations to be optimized and to assist in decisions on the justification of examination choices. Patient dosimetry is important for special cases such as for X-ray examinations of children and pregnant patients. It is also a key component of the quality control of X-ray equipment and procedures.