Mitsuhiro Inoue1, Kohei Okawa2,3, Junichi Taguchi2, Yoshifumi Hirota2, Yohei Yanagiya2, Chie Kikuchi2, Michio Iwabuchi4, Taro Murai5, Hiromitsu Iwata6,7, Hiroya Shiomi8,9, Izumi Koike6,10, Koshi Tatewaki11, Seiji Ohta11. 1. Department of Radiotherapy Quality Management, Yokohama CyberKnife Center, 574-1, Ichisawa-cho, Asahi-ku, Yokohama, 241-0014, Japan. m-inoue@syck.jp. 2. Department of Radiotherapy Quality Management, Yokohama CyberKnife Center, 574-1, Ichisawa-cho, Asahi-ku, Yokohama, 241-0014, Japan. 3. Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan. 4. Department of Radiation Therapy, Itabashi Chuo Medical Center, Tokyo, Japan. 5. Department of Radiology, Nagoya City University Graduate School of Medical Science, Nagoya, Japan. 6. Department of Radiation Oncology, Yokohama CyberKnife Center, Yokohama, Japan. 7. Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan. 8. Soseikai Clinic CyberKnife Center, Kyoto, Japan. 9. Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, Japan. 10. Department of Radiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan. 11. Department of Neurosurgery, Yokohama CyberKnife Center, Yokohama, Japan.
Abstract
PURPOSE: To analyze the factors affecting the tracking accuracy of the CyberKnife Synchrony Respiratory Tracking System (SRTS). MATERIALS AND METHODS: A dynamic motion phantom (motion phantom) reproduced the respiratory motions of each patient treated with the SRTS using a ball as the target. CyberKnife tracked the ball using the SRTS, and this process was recorded by a video camera mounted on the linear accelerator head. The tracking error was evaluated from the images captured by the video camera. Multiple regression analysis was used to identify factors affecting tracking accuracy from 91 cases. RESULTS: The median tracking error was 1.9 mm (range 0.9-5.3 mm). Four factors affected the tracking accuracy: the average absolute amplitude of the tumor motion in the cranio-caudal (CC) direction (p = 0.007), average position gap due to the phase shift between the internal tumor and external marker positions in the CC direction (p < 0.001), and average velocity of the tumor in the CC (p < 0.001) and anterior-posterior directions (p = 0.033). CONCLUSION: We identified factors that affected tracking accuracy. This information may assist the identification of suitable margins that should be added to each patient's clinical target volume.
PURPOSE: To analyze the factors affecting the tracking accuracy of the CyberKnife Synchrony Respiratory Tracking System (SRTS). MATERIALS AND METHODS: A dynamic motion phantom (motion phantom) reproduced the respiratory motions of each patient treated with the SRTS using a ball as the target. CyberKnife tracked the ball using the SRTS, and this process was recorded by a video camera mounted on the linear accelerator head. The tracking error was evaluated from the images captured by the video camera. Multiple regression analysis was used to identify factors affecting tracking accuracy from 91 cases. RESULTS: The median tracking error was 1.9 mm (range 0.9-5.3 mm). Four factors affected the tracking accuracy: the average absolute amplitude of the tumor motion in the cranio-caudal (CC) direction (p = 0.007), average position gap due to the phase shift between the internal tumor and external marker positions in the CC direction (p < 0.001), and average velocity of the tumor in the CC (p < 0.001) and anterior-posterior directions (p = 0.033). CONCLUSION: We identified factors that affected tracking accuracy. This information may assist the identification of suitable margins that should be added to each patient's clinical target volume.
Authors: Paul J Keall; Gig S Mageras; James M Balter; Richard S Emery; Kenneth M Forster; Steve B Jiang; Jeffrey M Kapatoes; Daniel A Low; Martin J Murphy; Brad R Murray; Chester R Ramsey; Marcel B Van Herk; S Sastry Vedam; John W Wong; Ellen Yorke Journal: Med Phys Date: 2006-10 Impact factor: 4.071
Authors: Mark K H Chan; Dora L W Kwong; Sherry C Y Ng; Anthony S M Tong; Eric K W Tam Journal: J Appl Clin Med Phys Date: 2012-11-08 Impact factor: 2.102