Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Phys Med. 2021 Jul;87:99-105. doi: 10.1016/j.ejmp.2021.06.005. Epub 2021 Jun 13.
A novel variable cycle-based respiratory guidance method was proposed to synchronize the patterns between patients' breathing and the magnetic excitation of synchrotron under the mode of full-energy depth scanning beam delivery, in order to improve the treatment precision and efficiency for carbon ion therapy.
Audio-visual biofeedback system with variable cycle-based respiratory guidance method was developed. We enrolled 6 healthy volunteers and a simulation study of the fixed cycle-based and variable cycle-based respiratory guidance with three treatment fractions was performed. A total of 72 breathing curves were collected for 4D dose calculations with three 4DCT datasets of lung tumor cases. Target dose coverage (D95: the percent dose covering 95% of the target), dose homogeneity (D5-D95), and treatment time were analyzed. The Wilcoxon signed-rank test was used for statistical difference analysis, and p < 0.05 was considered significant.
With the variable cycle-based respiratory guidance method, the breath hold phase of breathing curve could be synchronized with the synchrotron flat-top phase over time. The dose homogeneity was improved by factors of 1.94-2.92 compared to the fixed cycle-based respiratory guidance maneuvers alone or in combination with gating technique. Moreover, the treatment efficiency increased by 11-23%, depending on the duty cycle settings of the gating window.
The proposed variable cycle-based respiratory guidance method could improve both the treatment efficiency and precision under the mode of the full-energy depth scanning beam delivery for synchrotron-based carbon ion therapy.
为了提高碳离子治疗的精度和效率，提出了一种基于可变周期的呼吸引导方法，以在全能量深度扫描束传递模式下，使患者呼吸与同步加速器的磁激励模式同步。
开发了基于可变周期的视听生物反馈系统。我们招募了 6 名健康志愿者，并对基于固定周期和可变周期的呼吸引导进行了模拟研究，共进行了三个治疗部分。对于 4D 剂量计算，使用三个肺部肿瘤病例的 4DCT 数据集，共采集了 72 条呼吸曲线。分析了靶区剂量覆盖率（D95：覆盖 95%靶区的剂量百分比）、剂量均匀性（D5-D95）和治疗时间。采用 Wilcoxon 符号秩检验进行统计学差异分析，p<0.05 认为有显著差异。
采用基于可变周期的呼吸引导方法，呼吸曲线的屏气阶段可以随着时间与同步加速器的平顶阶段同步。与单独采用固定周期呼吸引导或与门控技术相结合相比，剂量均匀性提高了 1.94-2.92 倍。此外，治疗效率提高了 11%-23%，这取决于门控窗的占空比设置。
提出的基于可变周期的呼吸引导方法可以在基于同步加速器的碳离子治疗的全能量深度扫描束传递模式下，提高治疗效率和精度。
