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目的:基于Xsight脊柱追踪系统对胸椎转移瘤治疗前摆位及治疗中体位稳定性进行定量分析,以期为临床应用提供参考。方法:选择10例行射波刀(Cyber Knife,CK)治疗的胸椎转移瘤患者,采用真空垫行体位固定,应用Xsight脊柱追踪系统进行追踪治疗,并在首次治疗后做等中心十字线标记用于后续治疗的摆位参考;治疗过程中每隔60 s采集一次正交图像,并参考数字重建图像(digital reconstructedly radiograph,DRR)行配准校正且记录其误差,分析治疗分次内体位稳定性以及治疗照射误差。结果:患者治疗前分次间左右(X)、头脚(Y)、垂直(Z)3个方向的线性摆位误差(系统误差±随机误差)分别为(1.66±3.48)、(0.12±5.88)、(0.08±3.54)mm,推算其常规外放边界分别为7.5、5.0、3.1 mm;分次内平移误差均小于0.9 mm,旋转误差均小于0.8°;CK治疗过程中X、Y、Z 3个方向的治疗照射误差分别为0.34、0.31、0.25 mm。结论:CK治疗中运用首分次等中心标记法实现了对常规治疗等中心摆位的误差分析,为胸椎转移瘤临床常规治疗提供了参考;同时,由于患者体位变化引起的照射误差较小,实现了对靶区照射的高度准确性。
OBJECTIVE: To quantitatively analyze the position of thoracic metastases and the stability of their position during treatment based on the Xsight spinal tracking system in order to provide reference for clinical application. Methods: Ten patients with metastatic thoracic tumors treated with cyberknife (CK) were selected. The patients were fixed with a vacuum pad and were followed up by the Xsight spinal tracking system. After the first treatment, they were marked with isosceles crosshairs For reference in the follow-up treatment. Orthogonal images were collected every 60 seconds during the treatment and the errors were recorded with reference to the digitally reconstructed radiograph (DRR) lines. The body position stability And the treatment of irradiation error. Results: The linear errors (systematic errors ± random errors) in the three directions before and after treatment were (1.66 ± 3.48), (0.12 ± 5.88 ), And (0.08 ± 3.54) mm, respectively, and the conventional extracranial boundaries were estimated to be 7.5, 5.0 and 3.1 mm respectively. The translational errors within the sub-grading were all less than 0.9 mm and the rotation errors were both less than 0.8 °. X, Y and Z The irradiation errors in three directions were 0.34, 0.31 and 0.25 mm respectively. CONCLUSION: The error analysis of routine center setting in CK treatment by using the first sub-center labeling method provides a reference for routine clinical treatment of thoracic metastases. At the same time, due to the small error of patient position, Achieved a high degree of accuracy of target irradiation.