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

Global availability of dosimetry audits in radiotherapy: The IAEA dosimetry audit networks database

The International Atomic Energy Agency (IAEA) has established a database describing activities of dosimetry audit networks (DAN) in radiotherapy. Since 2010 the data on different aspects of the dosimetry audit have been collected. This information has allowed for the analysis and comparison of current practices in dosimetry auditing activities worldwide. Overall, 79 organizations in 58 countries confirmed that they offer dosimetry audit services for radiotherapy; however, access of radiotherapy centres to the audit remains insufficient. Increased availability of audits is necessary to improve dosimetry practices, reduce the likelihood of errors and the consequences that would result for patients’ health

Postal dose audits for radiotherapy centers in Latin America and the Caribbean: trends in 1969-2003 Auditorías de las dosis usadas en centros de radioterapia en América Latina y el Caribe: tendencias observadas en el período de 1969-2003

Since 1969 the International Atomic Energy Agency and the World Health Organization (along with the Pan American Health Organization, working with countries in Latin America and the Caribbean) have operated postal dosimetry audits based on thermoluminescent dosimetry (TLD) for radiotherapy centers. The purpose of these audits is to provide an independent dosimetry check of radiation beams used to treat cancer patients. The success of radiotherapy treatment depends on accurate dosimetry. Over the period of 1969 through 2003 the calibration of approximately 5 200 photon beams in over 1 300 radiotherapy centers in 115 countries worldwide was checked. Of these audits, 36% were performed in Latin America and the Caribbean, with results improving greatly over the years. Unfortunately, in several instances large TLD deviations have confirmed clinical observations of inadequate dosimetry practices in hospitals in various parts of the world or even accidents in radiotherapy, such as the one that occurred in Costa Rica in 1996. Hospitals or centers that operate radiotherapy services without qualified medical physicists or without dosimetry equipment have poorer results than do hospitals or centers that are properly staffed and equipped. When centers have poor TLD results, a follow-up program can help them improve their dosimetry status. However, to achieve audit results that are comparable to those for centers in industrialized countries, additional strengthening of the radiotherapy infrastructure in Latin America and the Caribbean is needed.Desde 1969, el Organismo Internacional de Energía Atómica y la Organización Mundial de la Salud (junto con la Organización Panamericana de la Salud en países de América Latina y el Caribe) han puesto en marcha un programa de auditorías dosimétricas por correo que se basa en la dosimetría termoluminiscente (DTL) para servicios de radioterapia. El objetivo del programa es ofrecer una verificación dosimétrica independiente de la calibración de los haces de radiación que se usan para tratar a los enfermos de cáncer. La obtención de buenos resultados en radioterapia depende de una dosimetría exacta. Entre 1969 y 2003 se verificó la calibración de aproximadamente 5 200 haces de fotones en más de 1 300 centros de 115 países de todo el mundo. El 36% de esas auditorías se efectuaron en América Latina y el Caribe, donde a lo largo de los años se observó un mejoramiento de los resultados. Por desgracia, ha habido varios casos en servicios de radioterapia de varias partes del mundo en los que las grandes desviaciones de la DTL han confirmado las observaciones clínicas de prácticas dosimétricas inadecuadas e incluso de accidentes de radioterapia como el ocurrido en Costa Rica en 1996. Los hospitales o centros cuyos servicios de radioterapia funcionan sin contar con físicos médicos calificados o que carecen de equipo de dosimetría obtienen peores resultados que los dotados de personal y equipo adecuados. Cuando se obtienen malos resultados en las mediciones de DTL en un determinado centro, un programa de seguimiento puede ayudarlo a mejorar la dosimetría. No obstante, para lograr resultados de auditoría semejantes a los obtenidos por los centros de los países industrializados, es necesario seguir fortaleciendo la infraestructura de la radioterapia en América Latina y el Caribe

END-TO-END AUDIT: COMPARISON OF TLD AND LITHIUM FORMATE EPR DOSIMETRY

The aim of this study was to test two different solid state dosimetry systems for the purpose of end-to-end audits of radiotherapy volumetric modulated arc therapy (VMAT) technique; a lithium formate electron paramagnetic resonance system and a lithium fluoride thermoluminescent dosimetry system. As a complement to the solid state systems, ion chamber measurements were performed. A polystyrene phantom with a planning target volume (PTV) and an organ at risk (OAR) structure was scanned using CT. A VMAT dose plan was optimized to deliver 2 Gy to the target volume and to minimize the dose to the OAR. The different detectors were inserted into the phantom and the planned dose distribution was delivered. The measured doses were compared to the treatment planning system (TPS) calculated doses. Good agreement was found between the TPS calculated and the measured doses, well accepted for the dose determinations in remote dosimetry audits of VMAT treatment technique.Funding Agencies|Swedish Cancer foundation [110322, E2.40.18]</p

Radiotherapy capacity in European countries : an analysis of the Directory of Radiotherapy Centres (DIRAC) database

Radiotherapy is used for cure or palliation in around half of patients with cancer. We analysed data on radiotherapy equipment in 33 European countries registered in the Directory of Radiotherapy Centres (DIRAC) database, managed by the International Atomic Energy Agency. As of July, 2012, Europe had 1286 active radiotherapy centres. The average number of teletherapy machines per radiotherapy centre ranged from 1·2 to 7·0 in different countries. Nordic countries, the UK, the Netherlands, and Slovenia all have large centres with four to ten teletherapy machines. Most western and southern European countries have several small centres with one or two machines, with few larger centres. The fragmentation in radiotherapy services that prevails in many European countries might affect the economic burden of radiotherapy and its quality. Eastern and southeastern European countries need to expand and modernise their radiotherapy equipment

Improving the quality of radiation oncology: 10years' experience of QUATRO audits in the IAEA Europe Region.

BACKGROUND AND PURPOSE: The IAEA has developed a methodology for comprehensive quality audits of radiotherapy practices called Quality Assurance Team for Radiation Oncology (QUATRO). This study explores the factors that impacted quality of care among QUATRO audited centres in the IAEA Europe Region. MATERIALS AND METHODS: The 31 QUATRO reports collected over 10years include extensive data describing the quality of radiotherapy at the audited centres. A coding key was developed to aggregate and review these data in terms of recommendations for improvement and positive findings (commendations). RESULTS: Overall 759 recommendations and 600 commendations were given. Eight centres recognized as centres of competence differed from other centres mostly because they operated complete quality management systems and were adequately staffed. Other centres had excessive staff workloads and many gaps in the process of care. Insufficient equipment levels were prevalent. Patient centredness, communication, dosimetry, quality control and radiation protection were frequently commended by QUATRO. CONCLUSIONS: This analysis points to barriers to quality care such as insufficient staffing, education/training, equipment and lack of quality management. It highlights the correlation between the human resources availability and quality of care. It has also identified common action items for enhancing quality of radiotherapy programmes in the Regio

Dosimetric inter-institutional comparison in European radiotherapy centres: Results of IAEA supported treatment planning system audit.

BACKGROUND AND PURPOSE: One of the newer audit modalities operated by the International Atomic Energy Agency (IAEA) involves audits of treatment planning systems (TPS) in radiotherapy. The main focus of the audit is the dosimetry verification of the delivery of a radiation treatment plan for three-dimensional (3D) conformal radiotherapy using high energy photon beams. The audit has been carried out in eight European countries - Estonia, Hungary, Latvia, Lithuania, Serbia, Slovakia, Poland and Portugal. The corresponding results are presented. MATERIAL AND METHODS: The TPS audit reviews the dosimetry, treatment planning and radiotherapy delivery processes using the \u27end-to-end\u27 approach, i.e. following the pathway similar to that of the patient, through imaging, treatment planning and dose delivery. The audit is implemented at the national level with IAEA assistance. The national counterparts conduct the TPS audit at local radiotherapy centres through on-site visits. TPS calculated doses are compared with ion chamber measurements performed in an anthropomorphic phantom for eight test cases per algorithm/beam. A set of pre-defined agreement criteria is used to analyse the performance of TPSs. RESULTS: TPS audit was carried out in 60 radiotherapy centres. In total, 190 data sets (combination of algorithm and beam quality) have been collected and reviewed. Dosimetry problems requiring interventions were discovered in about 10% of datasets. In addition, suboptimal beam modelling in TPSs was discovered in a number of cases. CONCLUSIONS: The TPS audit project using the IAEA methodology has verified the treatment planning system calculations for 3D conformal radiotherapy in a group of radiotherapy centres in Europe. It contributed to achieving better understanding of the performance of TPSs and helped to resolve issues related to imaging, dosimetry and treatment planning

Radiotherapy capacity in Europe – Authors' reply

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