Determination of patient-specific trajectory for biaxially rotational dynamic-radiation therapy using a new O-ring-shaped image guided radiotherapy system

作     者：Hirashima, Hideaki Adachi, Hiroki Ono, Tomohiro Nakamura, Mitsuhiro Ono, Yuka Iwai, Takahiro Yoshimura, Michio Mizowaki, Takashi 

作者机构：Kyoto Univ Grad Sch Med Dept Radiat Oncol & Image Appl Therapy 54 Kawahara choSakyo ku Kyoto 6068507 Japan Hitachi High Tech Corp X ray Therapy Div Healthcare Business Grp Therapy Syst Business Tokyo Japan Shiga Gen Hosp Dept Radiat Oncol Shiga Japan Kyoto Univ Grad Sch Med Dept Adv Med Phys 53 Kawahara choSakyo ku Kyoto 6068507 Japan 

出 版 物：《PHYSICS & IMAGING IN RADIATION ONCOLOGY》 (Phy. Imaging Radiat. Oncol.)

年 卷 期：2025年第33卷

页      面：100698-100698页

基　　金：Japan Agency for Medical Research and Development (AMED) [24ck0106924h0001] 

主　　题：Patient-specific trajectory search Dijkstra algorithm Pancreatic cancer BROAT-RT 

摘      要：Background and purpose: This study developed a trajectory search method for biaxially rotational dynamic- radiation therapy (BROAD-RT) using a new O-ring-shaped linac, aimed at identifying a patient-specific trajectory in a commercial treatment planning system. Subsequently, its efficacy in the treatment of pancreatic cancer was assessed. Materials and methods: BROAD-RT is a beam delivery technique in which the gantry and O-ring are simultaneously rotated around two axes. A beam s eye view-based structure map was generated, and the Dijkstra algorithm was then applied to explore the BROAD-RT for minimizing radiation doses to critical organs in RayStation. This procedure was evaluated in 10 patients with pancreatic cancer. For each patient, two different plans were created: volumetric modulated arc therapy (VMAT) plan with coplanar and BROAD-RT trajectory. The effects of different trajectories on the plan and dosimetric indices were assessed for each delivery technique. Results: The mean modulation complexity score for VMAT (MCSv) and aperture area (AA) (x103 cm2) were 0.3 f 0.0 and 24.8 f 3.9 for the coplanar trajectory and 0.4 f 0.1 and 35.2 f 7.1 for the BROAD-RT trajectory, respectively, with both MCSv (p = 5 x 10- 5) and AA (p = 0.0002) values significantly higher for the BROAD-RT trajectory. Dose difference between the coplanar and BROAD-RT trajectories reduced the dose to the stomach and duodenum. Conclusions: Our study conducted an automated search for patient-specific BROAD-RT trajectory using a new Oring-shaped linac and implemented these trajectories in RayStation. Dose distributions were reduced in the intermediate-dose regions with BROAD-RT trajectory.