Evaluation of the Accuracy of a 3D Surface Imaging System for Patient Setup in Head and Neck Cancer Radiotherapy
Evaluation of the Accuracy of a 3D Surface Imaging System for Patient Setup in Head and Neck Cancer Radiotherapy
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DOI：
10.1016/j.ijrobp.2011.12.004
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发表时间：
2012-10-01
影响因子：
7
通讯作者：
Wu, Qiuwen
中科院分区：
文献类型：
--
作者：
Gopan, Olga;Wu, Qiuwen
目的：评估放疗期间头颈癌患者设置的三维 (3D) 表面成像系统 (AlignRT) 配准算法的准确性。 方法和材料：本研究纳入了 11 名患者，每名患者在治疗过程中每周重复进行 6 次螺旋计算机断层扫描 (CT)（总共 77 次 CT，包括计划 CT）。 AlignRT 配准中使用的患者表面图像不是由 3D 相机捕获的；相反，它们源自这些 CT 的皮肤轮廓，从而消除了固定面罩的问题。将 AlignRT 中基于 CT 皮肤轮廓的表面配准结果与 Pinnacle 3 中基于骨解剖配准的结果进行比较，后者被认为是黄金标准。分析了刚性和非刚性类型的设置误差，并研究了肿瘤收缩的影响。结果：AlignRT 中的最大配准误差在所有方向上旋转为 0.2 度，平移为 0.7 毫米。当应用于实际患者数据时，头部区域的刚性对准精度为旋转 1.1 度、0.8 度和 2.2 度，沿垂直轴、纵向轴和横向轴平移 4.5 毫米、2.7 毫米和 2.4 毫米（置信度为 90%）。准确性受到治疗过程中患者体重减轻的影响，这是患者特定的。有选择地选择表面区域提高了配准精度。在 90% 置信水平下，非刚性配准的差异在 1.9 度、2.4 度和 4.5 度以及 10.1、11.9 和 6.9 毫米处要大得多。结论：3D 表面成像系统能够以良好的精度检测头颈癌的刚性设置误差。需要进一步的研究来提高检测非刚性设置错误的准确性。 (C) 2012 爱思唯尔公司。
Purpose: To evaluate the accuracy of three-dimensional (3D) surface imaging system (AlignRT) registration algorithms for head-and-neck cancer patient setup during radiotherapy.Methods and Materials: Eleven patients, each undergoing six repeated weekly helical computed tomography (CT) scans during treatment course (total 77 CTs including planning CT), were included in the study. Patient surface images used in AlignRT registration were not captured by the 3D cameras; instead, they were derived from skin contours from these CTs, thereby eliminating issues with immobilization masks. The results from surface registrations in AlignRT based on CT skin contours were compared to those based on bony anatomy registrations in Pinnacle 3, which was considered the gold standard. Both rigid and nonrigid types of setup errors were analyzed, and the effect of tumor shrinkage was investigated.Results: The maximum registration errors in AlignRT were 0.2 degrees for rotations and 0.7 mm for translations in all directions. The rigid alignment accuracy in the head region when applied to actual patient data was 1.1 degrees, 0.8 degrees, and 2.2 degrees in rotation and 4.5, 2.7, and 2.4 mm in translation along the vertical, longitudinal, and lateral axes at 90% confidence level. The accuracy was affected by the patient's weight loss during treatment course, which was patient specific. Selectively choosing surface regions improved registration accuracy. The discrepancy for nonrigid registration was much larger at 1.9 degrees, 2.4 degrees, and 4.5 degrees and 10.1, 11.9, and 6.9 mm at 90% confidence level.Conclusions: The 3D surface imaging system is capable of detecting rigid setup errors with good accuracy for head-and-neck cancer. Further investigations are needed to improve the accuracy in detecting nonrigid setup errors. (C) 2012 Elsevier Inc.