基于CyberKnife脊柱追踪系统的胸椎转移瘤放疗摆位误差分析  

Analysis of set-up errors of Cyber Knife therapy for thoracic spine metastases based on Xsight spine tracking system

作　　者：解传滨[1] 鞠忠建[1] 陈高翔[1] 刚颖[1] 徐寿平[1] 巩汉顺[1] 王小深[1] 王金媛[1] 欧光明[1] 

机构地区：[1]解放军总医院放疗科,北京100853

出　　处：《医疗卫生装备》2015年第11期87-90,共4页Chinese Medical Equipment Journal

基　　金：国家自然科学基金资助项目(11275105)

摘　　要：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 analyze quantitatively the pretherapy setup and intratherapy posture stability for the thoracic metastatic tumor with Xsight spine tracking system. Methods Ten thoracic metastatic tumor patients undergoing Cyber Knife（CK） treatment were fixed with vacuum fusions. With Xsight spine tracking system applied, isocenter reticles were formed after the first treatment procedure to provide references for the setup of the following treatment. The intrafractional set-up stability and errors were analyzed using the translational and rotational deviations after registering and comparing the orthogonal images（every 60 s） with the DRR images. Results The intrafractional translational set-up errors（SD） of X-axis,Y-axis and Z-axis were（1.66 ±3.48）,（0.12 ±5.88） and（0.08 ±3.54） mm. The margins in conventional radiotherapy were calculated as 7.5, 5.0 and 3.1 mm, The average translational and rotational set-up errors during treatment were less than 0.9 mm and 0.8°. The delivery errors（X,Y, Z） during CK treatment were 0.34, 0.31 and0.25 mm. Conclusion The isocenter set-up errors in the conventional radiotherapy are achieved by the method of marked set-up in the first fraction of CK and provide references for the clinical application. The deviations caused by the setup errors are very little during the CK treatment, and the precision of target is realized during the irradiation.

关 键 词：射波刀 胸椎转移瘤 脊柱追踪 摆位误差 

分 类 号：R738.1[医药卫生—肿瘤] R730.55[医药卫生—临床医学]