脊柱追踪相关参数对射波刀定位误差影响  

Effects of spine tracking parameters on the positioning errors of cyberknife

作　　者：赵瑞[1] 王震岳[1] 李莎[1] 陆军[1] 

机构地区：[1]兰州军区兰州总医院放疗科,735030

出　　处：《中华放射肿瘤学杂志》2016年第5期504-507,共4页Chinese Journal of Radiation Oncology

摘　　要：目的探讨脊柱ROI、追踪范围和实时影像对比度系数与射波刀定位误差的关系。方法利用肺追踪体模制定脊柱追踪计划并进行治疗，通过目标定位系统进行体模预置，获得体模实时预置影像及定位误差：以实时预置影像为基础，改体模脊柱ROI大小、追踪范围和实时影像对比度系数，观察体模定位误差及相关参数的改变。采用Pearson法相关分析。结果追踪范围的改变不会引起脊柱追踪定位误差的改变，追踪范围与脊柱追踪定位误差无关联（R=0，P=1）；ROI大小和影像对比度系数的改变对脊柱追踪平移误差无影响，但对脊柱追踪旋转误差有影响，主要表现在左右旋转误差改变（R=0．533、0．693，P=0．002、0．026），其中尤以实时影像对比度的影响最为明显，其变化幅度高达2．2°。结论除追踪范围的改变不会影响脊柱追踪的定位误差外，ROI大小和影像对比度系数的改变均会导致脊柱追踪的定位误差不同程度的变化，在射波刀治疗中应引起足够重视。Objective To investigate the effects of spine region of interest （ ROI）, tracking range, and real-time image contrast ratio on the positioning errors of cyberknife. Methods The LTT dynamic phantom was used to develop a spine tracking plan and perform treatment, and the target positioning system was used to preset the phantom and obtain real-time preset image and positioning error. Based on the real- time preset image, spine ROI, tracking range, and real-time image contrast ratio were changed to observe the changes in positioning error and related parameters. Pearson correlation analysis was perfomled. Results The change in tracking range did not change the positioning error in spine tracking, and tracking range was not correlated with positioning error （ R = 0, P = 1 ）. The changes in ROI and image contrast ratio did not affect the translation error, but affected the rotation error, especially the rotation error in left-right direction （ r = 0. 533 and 0. 693, P= 0. 002 and 0. 026）. The image contrast ratio had the most obvious effect, with an amplitude of variation up to 2. 2°. Conclusions The change in tracking range does not affect the positioning errors in spinal tracking, but the changes in ROI and image contrast ratio can cause varying degrees of changes in positioning errors, which should be taken seriously in cyberknife treatment.

关 键 词：射波刀 影像引导 脊柱追踪 感兴趣区 影像对比度 

分 类 号：R730.55[医药卫生—肿瘤]