Zhou Zhen, Dong Tingting, Wang Bei, Wang Zhiqun, Zhu Heling, Li Wenbo, Yang Bo, Qiu Jie
Department of Radiation Oncology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
Technol Cancer Res Treat. 2025 Jan-Dec;24:15330338251322075. doi: 10.1177/15330338251322075.
To investigate the optimal radiotherapy regimen for synchronous bilateral breast cancer (SBBC) by utilizing dosimetric and radiobiological indicators, and to assess the impact of applying an optical surface monitoring system(OSMS) on the precision of SBBC radiotherapy treatment.
Nine patients with SBBC who underwent breast-conserving radiotherapy were retrospectively selected. Four treatment plans were designed for each patient using the Versa HD (Elekta, Stockholm) accelerator: single-isocenter intensity-modulated radiotherapy/volumetric modulated arc therapy(IMRT-ISO1/VMAT-ISO1) and dual-isocenter IMRT/VMAT(IMRT-ISO2/VMAT-ISO2), with a prescription dose of 42.4 Gy in 16 fractions. Dosimetric parameters and radiobiological impact were measured for the target and organs at risk(OARs). The monitoring log files of three SBBC patients were analyzed to quantitatively assess real-time delta shifts encompassing six degrees of freedom (DOFs) during intrafraction and interfraction treatment processes.
Compared to both the IMRT techniques, the VMAT techniques offered superior target conformity, uniformity, and dose fall-off capability. Among the four treatment plans, VMAT-ISO1 exhibited optimal performance by significantly reducing radiation exposure volume to OARs while maintaining exceptional precision in dose delivery and execution efficiency. The tumor control probability (TCP) was exceeded by 98.5% for all four modalities. According to the OSMS logs, the maximum absolute error in translational motion during the treatment of three SBBC patients was predominantly manifested along the vertical(VRT) axis, with an mean value of 2.2 mm. Additionally, it was observed that the coronal plane (YAW) exhibited the largest error in terms of rotational angle, with an mean deviation of 1.1°.
The VMAT-ISO1 technique demonstrates apparent dosimetric and radiobiological advantages in SBBC radiotherapy, ensuring precise dose delivery and shortening treatment durations. The accuracy of SBBC radiotherapy is ensured by OSMS through pre-treatment positioning correction and real-time monitoring throughout the treatment process.
利用剂量学和放射生物学指标研究同步双侧乳腺癌（SBBC）的最佳放疗方案，并评估应用光学表面监测系统（OSMS）对SBBC放射治疗精度的影响。
回顾性选取9例接受保乳放疗的SBBC患者。使用Versa HD（医科达，斯德哥尔摩）加速器为每位患者设计4种治疗计划：单等中心调强放疗/容积调强弧形放疗（IMRT-ISO1/VMAT-ISO1）和双等中心IMRT/VMAT（IMRT-ISO2/VMAT-ISO2），处方剂量为42.4 Gy，分16次照射。测量靶区和危及器官（OARs）的剂量学参数和放射生物学影响。分析3例SBBC患者的监测日志文件，以定量评估分次内和分次间治疗过程中包括六个自由度（DOF）的实时增量位移。
与两种IMRT技术相比，VMAT技术具有更好的靶区适形性、均匀性和剂量跌落能力。在四种治疗计划中，VMAT-ISO1表现出最佳性能，在显著减少OARs的辐射暴露体积的同时，保持了剂量递送的卓越精度和执行效率。所有四种模式的肿瘤控制概率（TCP）均超过98.5%。根据OSMS日志，3例SBBC患者治疗期间平移运动的最大绝对误差主要沿垂直（VRT）轴表现，平均值为2.2 mm。此外，观察到冠状面（YAW）在旋转角度方面误差最大，平均偏差为1.1°。
VMAT-ISO1技术在SBBC放疗中显示出明显的剂量学和放射生物学优势，确保了精确的剂量递送并缩短了治疗时间。OSMS通过治疗前定位校正和治疗过程中的实时监测确保了SBBC放疗的准确性。
