Zhang Huailing, Zhao Guoru, Djajaputra David, Xie Yaoqin
School of Information Engineering, Guangdong Medical College, Dongguan, Guangdong 523808, China.
Key Laboratory for Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Avenue, Shenzhen, Guangdong 518055, China.
ScientificWorldJournal. 2014;2014:408019. doi: 10.1155/2014/408019. Epub 2014 May 13.
To report the characteristics of pancreas motion as tracked using implanted fiducials during radiotherapy treatments with CyberKnife.
Twenty-nine patients with pancreas cancer treated using CyberKnife system were retrospectively selected for this study. During the treatment, the deviation is examined every 3-4 nodes (~45 s interval) and compensated by the robot. The pancreas displacement calculated from X-ray images acquired within the time interval between two consecutive couch motions constitute a data set.
A total of 498 data sets and 4302 time stamps of X-ray images were analyzed in this study. The average duration for each data set is 634 s. The location of the pancreas becomes more dispersed as the time elapses. The acquisition frequency depends on the prespecified movement distance threshold of pancreas. If the threshold between two consecutive images is 1 mm, the acquisition frequency should be less than 30 s, while if the threshold is 2 mm, the acquisition frequency can be around 1 min.
The pancreas target moves significantly and unpredictably during treatment. Effective means of compensating the intrafractional movement is critical to ensure adequate dose coverage of the tumor target.
报告在使用射波刀进行放射治疗期间，通过植入基准标记追踪胰腺运动的特征。
本研究回顾性选取了29例使用射波刀系统治疗的胰腺癌患者。治疗期间，每3 - 4个节点（间隔约45秒）检查一次偏差，并由机器人进行补偿。从两个连续治疗床运动的时间间隔内获取的X射线图像计算出的胰腺位移构成一个数据集。
本研究共分析了498个数据集和4302个X射线图像时间戳。每个数据集的平均持续时间为634秒。随着时间的推移，胰腺的位置变得更加分散。采集频率取决于预先设定的胰腺移动距离阈值。如果两个连续图像之间的阈值为1毫米，采集频率应小于30秒，而如果阈值为2毫米，采集频率可以约为1分钟。
胰腺靶区在治疗期间移动显著且不可预测。补偿分次内运动的有效方法对于确保肿瘤靶区有足够的剂量覆盖至关重要。
