Vol.7 No.4 2015

Research paper : International standardization of four dimensional radiotherapy system (Y. HIRATA et al.)−235−Synthesiology - English edition Vol.7 No.4 (2015) and producing the 4DRT systems, government agencies, public research organizations, universities, academic societies, and other interested parties must work together.Based on the basic concept explained in subchapter 4.1, international standardization from the standpoint of system aspects is necessary.The 4DRT system is a complex system comprised of several components such as the X-IGRT equipment that mainly monitors the tumor state, the external beam equipment that directly treats the tumor, the treatment table, and the treatment planning equipment that appropriately controls the equipment. On the other hand, since the international standardization and the creation of de facto standards are being done to integrate the above components of the 4DRT system, it is unrealistic to create completely new standards for these components. As a result, it is unclear where the responsibility lies in coordinating and connecting these components, and this creates concern for patient safety. If we overlook this point, it may cause medical accidents such as excessive or under irradiation.Originally in the IEC TC62/SC62C, the main task was to create the standards for independent equipment, and therefore, the system standard was not created. To supplement this, the Japanese national commission proposed the NP (62C/580/NP) for creating a completely new system standard for the “Requirements of safety and performance of complex real-time controlled radiotherapy systems for a moving target,” and the NP was approved by international voting. In this NP, it is expected that the five items discussed in subchapter 4.3 will be officially standardized to assure the overall safety of the 4DRT systems.In addition, it is becoming certain that the system will be included in the new scope proposal of the IEC TC62/SC62C, and the system standard of radiotherapy systems will be created in the IEC. Of course, in developing a completely new system standard, we must proceed with ingenuity to avoid disadvantages to individual companies. However, we shall promote the development of new system standards to ensure safety of radiotherapy that can track tumor motion, for both large and small companies.In the future, it is expected that the international standardization of 4DRT in the IEC will be developed for both the independent equipment standard and the system standard as shown in Fig. 7.AcknowledgementsThis research was supported by the R&D Program of International Standards, Ministry of Economy, Trade and Industry. The research was also supported by Associate Professor Kenji Naoe and Associate Professor Takashi Kozuka of the Graduate School of Medicine, Hokkaido University, and the people of JIRA. Work is done concurrentlyUpdating equipment standardsNew system standardsExisting equipment standardsIEC TC62/SC62C WG1Requirements of safety and performance of complex real-time controlled radiotherapy systems for a moving target(Japanese proposals)IEC TC62/SC62C NPImprovement of safety of 4DRTFig. 7 Future direction of the international standardization of 4DRTReferences[1]Ministry of Health, Labour and Welfare: Vital statistics, http://www.mhlw.go.jp/toukei/saikin/hw/jinkou/kakutei10/[2]Japanese Radiation Oncology Data Center: Japanese Structure Survey of Radiation Oncology in 2010 (First Report) (in Japanese). http://www.jastro.or.jp/aboutus/datacenter.php[3]A. Matsuda, T. Matsuda, A. Shibata, K. Katanoda, T. Sobue, H. 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