射波刀脊柱追踪系统治疗精度与感兴趣区的相关性研究

A study of the accuracy of Cyberknife Xsight spine tracking system with different region of interest

目的:研究不同感兴趣区节点的分布对射波刀脊柱追踪系统治疗精度的影响。方法:通过对Lucy头颈部仿真模体设定10种不同情况分别制定各自端到端验证计划。每个计划分别在ROI Height为40 mm、60 mm、80 mm的条件下进行摆位并投照,投照后对球方内胶片进行扫描分析。评估三种ROI分布下系统分析处理正交影像数据的时间、错误节点数(False Node)、X轴目标配对公差阈值(dxAB)、r轴目标配对公差阈值(drAB)以及照射在左右(left)、头脚(superior)、前后[ant(A/L)、ant(A/S)、anterior]方向的误差和总体误差(total)。结果:摆位阶段ROI范围越大,系统处理分析影像数据的时间越长,False Node的数量也随之增加(P<0.05),dxAB和drAB的差异无统计学意义。投照误差方面,40 mm组与60 mm组在最终的整体照射精度上无显著差异;80 mm组在ant(A/L)、ant(A/S)、anterior和total上的投照误差高于60 mm组,差异有统计学意义(P<0.05)。结论:使用射波刀脊柱追踪系统时,应选择合适的ROI以覆盖脊柱区域。对于侧弯、驼背及动物实验的脊柱模型,放大ROI范围后脊柱追踪系统同样可以取得亚毫米级别的治疗精度。

Objective:To analyze impacts of distributions of different regions of interest(ROI)on the accuracy of Xsight spine tracking system(XSTS)of Cyberknife.Methods:The end-to-end verification plans were made respectively based on ten different settings or positions via head and neck Lucy phantom.Each plan was delivered under the conditions of height of ROI of 40 mm,60 mm,and 80 mm,respectively.The films in the cube were scanned and analyzed after the delivery.Based on the three distributions of ROI,the calculated time,False Node,dxAB,drAB,left error,anterior error and total error were analyzed.Results:The larger ROI ranges were in the setup phase,the longer calculated time to process and analyze the image data,and the more false nodes would be(P<0.05).There was no significant differences of dxAB and drAB.Similar irradiation accuracy was found between the 40 mm and 60 mm group.The ant(A/L)error,ant(A/S)error,anteriorerror and total error weregreater in the 80 mm group than those in the 60 mm group(P<0.05).Conclusion:Appropriate ROI should be selected to cover the spine volume with XSTS.For scoliosis,humpback and animal spine models,the XSTS can also achieve sub-millimeter treatment accuracy after enlarging the ROI range.