Hirashima Hideaki, Adachi Hiroki, Ono Tomohiro, Nakamura Mitsuhiro, Ono Yuka, Iwai Takahiro, Yoshimura Michio, Mizowaki Takashi
Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
X-ray Therapy Division, Therapy System Business, Healthcare Business Group, Hitachi High-Tech Corporation, Tokyo, Japan.
Phys Imaging Radiat Oncol. 2025 Jan 20;33:100698. doi: 10.1016/j.phro.2025.100698. eCollection 2025 Jan.
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.
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.
The mean modulation complexity score for VMAT (MCS) and aperture area (AA) (×10 cm) were 0.3 ± 0.0 and 24.8 ± 3.9 for the coplanar trajectory and 0.4 ± 0.1 and 35.2 ± 7.1 for the BROAD-RT trajectory, respectively, with both MCS (p = 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.
Our study conducted an automated search for patient-specific BROAD-RT trajectory using a new O-ring-shaped linac and implemented these trajectories in RayStation. Dose distributions were reduced in the intermediate-dose regions with BROAD-RT trajectory.
本研究针对一种新型O形环直线加速器，开发了一种用于双轴旋转动态放射治疗（BROAD-RT）的轨迹搜索方法，旨在在商业治疗计划系统中确定患者特异性轨迹。随后，评估了其在胰腺癌治疗中的疗效。
BROAD-RT是一种射束传输技术，其中机架和O形环同时围绕两个轴旋转。生成基于射野视角的结构地图，然后应用迪杰斯特拉算法在RayStation中探索BROAD-RT，以将关键器官的辐射剂量降至最低。对10例胰腺癌患者进行了该程序评估。对于每位患者，创建了两种不同的计划：具有共面和BROAD-RT轨迹的容积调强弧形治疗（VMAT）计划。评估了每种传输技术中不同轨迹对计划和剂量学指标的影响。
VMAT的平均调制复杂性评分（MCS）和孔径面积（AA）（×10 cm），共面轨迹分别为0.3±0.0和24.8±3.9，BROAD-RT轨迹分别为0.4±0.1和35.2±7.1，BROAD-RT轨迹的MCS（p = 5× ）和AA（p = 0.0002）值均显著更高。共面和BROAD-RT轨迹之间的剂量差异降低了胃和十二指肠的剂量。
我们的研究使用新型O形环直线加速器对患者特异性BROAD-RT轨迹进行了自动搜索，并在RayStation中实施了这些轨迹。BROAD-RT轨迹使中间剂量区域的剂量分布降低。
