Estimation of patient setup uncertainty using BrainLAB Exatrac X-Ray 6D system in image-guided radiotherapy
Estimation of patient setup uncertainty using BrainLAB Exatrac X-Ray 6D system in image-guided radiotherapy
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DOI：
10.1120/jacmp.v16i2.5102
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发表时间：
2015-01-01
影响因子：
2.1
通讯作者：
Mameli, Alessandra
中科院分区：
文献类型：
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作者：
Infusino, Erminia;Trodella, Lucio;Mameli, Alessandra
本研究的目的是评估ExacTrac X-Ray 6D系统脑部部位的设置不确定性，并提供最佳边缘指南。本研究纳入了15例脑肿瘤患者。每次治疗前，使用ExacTrac X-Ray 6D系统的两张X线图像验证患者位置和肿瘤靶定位。6D融合软件首先为CT图像生成在三个平移和三个旋转方向（六个自由度）上具有位置变化的各种DRR集。记录校正后的设置变化（平移和旋转），并在治疗前进行校正。3D偏差表示为平均值+/-标准差。使用货车Herk的定义计算不同X射线的随机误差（Sigma（sigma（i）、系统误差（mu（i））和组系统误差（M（mu（i）。((1))根据所有分次后采集的X射线图像计算平均设置误差。在垂直方向上存在中度患者间差异，系统误差和随机误差幅度的变化较小。在每个方向上测量的全局系统误差小于2.0 mm。所有患者的随机分量均较小，范围为0.1-0.3 mm。货车Herk（（1））和Stroom等人的侧向安全裕度（SM）分别为0.5 mm和2.6 mm，((2))颅尾轴分别为1.5 mm和3.4 mm，相对于前后轴为2.3 mm和3.9 mm。每日X线成像对于比较和评估不同解剖位置的治疗输送准确性至关重要。
The purpose of this study was to evaluate setup uncertainties for brain sites with ExacTrac X-Ray 6D system and to provide optimal margin guidelines. Fifteen patients with brain tumor were included in this study. Two X-ray images with ExacTrac X-Ray 6D system were used to verify patient position and tumor target localization before each treatment. The 6D fusion software first generates various sets of DRRs with position variations in both three translational and three rotational directions (six degrees of freedom) for the CT images. Setup variations (translation and rotation) after correction were recorded and corrected before treatment. The 3D deviations are expressed as mean +/- standard deviation. The random error (Sigma(sigma(i))), systematic error (mu(i)), and group systematic error (M(mu(i))) for the different X-ray were calculated using the definitions of van Herk.((1)) Mean setup errors were calculated from X-ray images acquired after all fractions. There is moderate patient-to-patient variation in the vertical direction and small variations in systematic errors and magnitudes of random errors are smaller. The global systematic errors were measured to be less than 2.0 mm in each direction. Random component of all patients are smaller ranging from 0.1-0.3 mm small. The safety margin (SM) to the lateral, is 0.5 mm and 2.6 mm for van Herk((1)) and Stroom et al.,((2)) respectively, craniocaudal axis is 1.5 mm and 3.4 mm, respectively, and with respect to the antero-posterior axis, 2.3 mm and 3.9 mm. Daily X-ray imaging is essential to compare and assess the accuracy of treatment delivery to different anatomical locations.