Hidenobu Tachibana1, Yukihiro Uchida2, Ryuta Miyakawa3, Mikiko Yamashita4, Aya Sato5, Satoshi Kito6, Daiki Maruyama7, Shigetoshi Noda8, Toru Kojima9, Hiroshi Fukuma10, Ryosuke Shirata11, Hiroyuki Okamoto12, Mitsuhiro Nakamura13, Yuma Takada14, Hironori Nagata15, Naoki Hayashi16, Ryo Takahashi17, Daisuke Kawai18, Masanobu Itano19. 1. Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 277-8577 Chiba, Japan; Radiation Safety and Quality Assurance Division, Hospital East, National Cancer Center, 277-8577 Chiba, Japan. Electronic address: htachiba@east.ncc.go.jp. 2. Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 277-8577 Chiba, Japan. Electronic address: yukuchid@east.ncc.go.jp. 3. Department of Radiology, Saiseikai Yokohamashi Tobu Hospital, 230-8765 Kanagawa, Japan. Electronic address: r_miyakawa@tobu.saiseikai.or.jp. 4. Department of Radiological Technology, Kobe City Medical Center General Hospital, 650-0047 Hyogo, Japan. Electronic address: m-yamashita@kcho.jp. 5. Department of Radiology, Itabashi Chuo Medical Center, 174-0051 Tokyo, Japan. 6. Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 113-8677 Tokyo, Japan. Electronic address: skitou@cick.jp. 7. Department of Medical Technology, Japanese Red Cross Medical Center, 150-8935 Tokyo, Japan. Electronic address: daimaru0620@yahoo.co.jp. 8. Department of Radiology, Kitasato University Hospital, 252-0375 Kanagawa, Japan. Electronic address: s-noda@kitasato-u.ac.jp. 9. Department of Radiation Oncology, Saitama Cancer Center, 362-0806 Saitama, Japan. 10. Department of Radiology, Nagoya City University Hospital, 467-8602 Aichi, Japan. 11. Department of Radiation Oncology, Shonan Kamakura General Hospital, 247-8533 Kanagawa, Japan. Electronic address: shirata@rg7.so-net.ne.jp. 12. Department of Radiation Oncology, The National Cancer Center, 104-0045 Tokyo, Japan. Electronic address: hiokamot@ncc.go.jp. 13. Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, 606-8507 Kyoto, Japan. Electronic address: m_nkmr@kuhp.kyoto-u.ac.jp. 14. Department of Radiology, Ogaki Tokushukai Hospital, 503-0015 Gifu, Japan. Electronic address: rt-toku@ogaki.tokushukai.or.jp. 15. Department of Radiation Oncology, Shonan Kamakura General Hospital, 247-8533 Kanagawa, Japan. 16. School of Health Sciences, Fujita Health University, 470-1192 Aichi, Japan. Electronic address: hayashi@fujita-hu.ac.jp. 17. Department of Radiation Oncology, The Cancer Institute Hospital of Japanese Foundation of Cancer Research, 135-8550 Tokyo, Japan. Electronic address: ryo.takahashi@jfcr.or.jp. 18. Division of Radiation Oncology, Kanagawa Cancer Center, 241-0815 Kanagawa, Japan. 19. Department of Radiation Oncology, Funabashi Municipal Medical Center, 273-8588 Chiba, Japan. Electronic address: majalhappy@yahoo.co.jp.
Abstract
PURPOSE: This report covers the first multi-institutional study of independent monitor unit (MU)/dose calculation verification for the CyberKnife, Vero4DRT, and TomoTherapy radiotherapy delivery systems. METHODS: A total of 973 clinical treatment plans were collected from 12 institutions. Commercial software employing the Clarkson algorithm was used for verification after a measurement validation study, and the doses from the treatment planning systems (TPSs) and verification programs were compared on the basis of the mean value ± two standard deviations. The impact of heterogeneous conditions was assessed in two types of sites: non-lung and lung. RESULTS: The dose difference for all locations was 0.5 ± 7.2%. There was a statistically significant difference (P < 0.01) in dose difference between non-lung (-0.3 ± 4.4%) and lung sites (3.5 ± 6.7%). Inter-institutional comparisons showed that various systematic differences were associated with the proportion of different treatment sites and heterogeneity correction. CONCLUSIONS: This multi-institutional comparison should help to determine the departmental action levels for CyberKnife, Vero4DRT, and TomoTherapy, as patient populations and treatment sites may vary between the modalities. An action level of ±5% could be considered for intensity-modulated radiation therapy (IMRT), non-IMRT, and volumetric modulated arc radiotherapy using these modalities in homogenous and heterogeneous conditions with a large treatment field applied to a large region of homogeneous media. There were larger systematic differences in heterogeneous conditions with a small treatment field because of differences in heterogeneity correction with the different dose calculation algorithms of the primary TPS and verification program.
PURPOSE: This report covers the first multi-institutional study of independent monitor unit (MU)/dose calculation verification for the CyberKnife, Vero4DRT, and TomoTherapy radiotherapy delivery systems. METHODS: A total of 973 clinical treatment plans were collected from 12 institutions. Commercial software employing the Clarkson algorithm was used for verification after a measurement validation study, and the doses from the treatment planning systems (TPSs) and verification programs were compared on the basis of the mean value ± two standard deviations. The impact of heterogeneous conditions was assessed in two types of sites: non-lung and lung. RESULTS: The dose difference for all locations was 0.5 ± 7.2%. There was a statistically significant difference (P < 0.01) in dose difference between non-lung (-0.3 ± 4.4%) and lung sites (3.5 ± 6.7%). Inter-institutional comparisons showed that various systematic differences were associated with the proportion of different treatment sites and heterogeneity correction. CONCLUSIONS: This multi-institutional comparison should help to determine the departmental action levels for CyberKnife, Vero4DRT, and TomoTherapy, as patient populations and treatment sites may vary between the modalities. An action level of ±5% could be considered for intensity-modulated radiation therapy (IMRT), non-IMRT, and volumetric modulated arc radiotherapy using these modalities in homogenous and heterogeneous conditions with a large treatment field applied to a large region of homogeneous media. There were larger systematic differences in heterogeneous conditions with a small treatment field because of differences in heterogeneity correction with the different dose calculation algorithms of the primary TPS and verification program.