トラマツ チエ
  寅松 千枝
   所属   医学部 医学科(東京女子医科大学病院)
   職種   非常勤講師
論文種別 原著
言語種別 英語
査読の有無 査読あり
表題 Integration of a real-time tumor monitoring system into gated proton spot-scanning beam therapy: an initial phantom study using patient tumor trajectory data.
掲載誌名 正式名:Medical physics
略  称:Med Phys
ISSNコード:24734209/00942405
掲載区分国外
巻・号・頁 40(7),pp.071729
著者・共著者 Matsuura Taeko, Miyamoto Naoki, Shimizu Shinichi, Fujii Yusuke, Umezawa Masumi, Takao Seishin, Nihongi Hideaki, Toramatsu Chie, Sutherland Kenneth, Suzuki Ryusuke, Ishikawa Masayori, Kinoshita Rumiko, Maeda Kenichiro, Umegaki Kikuo, Shirato Hiroki
発行年月 2013/07
概要 PURPOSE:In spot-scanning proton therapy, the interplay effect between tumor motion and beam delivery leads to deterioration of the dose distribution. To mitigate the impact of tumor motion, gating in combination with repainting is one of the most promising methods that have been proposed. This study focused on a synchrotron-based spot-scanning proton therapy system integrated with real-time tumor monitoring. The authors investigated the effectiveness of gating in terms of both the delivered dose distribution and irradiation time by conducting simulations with patients' motion data. The clinically acceptable range of adjustable irradiation control parameters was explored. Also, the relation between the dose error and the characteristics of tumor motion was investigated.METHODS:A simulation study was performed using a water phantom. A gated proton beam was irradiated to a clinical target volume (CTV) of 5 × 5 × 5 cm(3), in synchronization with lung cancer patients' tumor trajectory data. With varying parameters of gate width, spot spacing, and delivered dose per spot at one time, both dose uniformity and irradiation time were calculated for 397 tumor trajectory data from 78 patients. In addition, the authors placed an energy absorber upstream of the phantom and varied the thickness to examine the effect of changing the size of the Bragg peak and the number of required energy layers. The parameters with which 95% of the tumor trajectory data fulfill our defined criteria were accepted. Next, correlation coefficients were calculated between the maximum dose error and the tumor motion characteristics that were extracted from the tumor trajectory data.RESULTS:With the assumed CTV, the largest percentage of the data fulfilled the criteria when the gate width was ± 2 mm. Larger spot spacing was preferred because it increased the number of paintings. With a prescribed dose of 2 Gy, it was difficult to fulfill the criteria for the target with a very small effective depth (the
DOI 10.1118/1.4810966
PMID 23822433