Accuracy and inter-observer variability of 3D versus 4D cone-beam CT based image-guidance in SBRT for lung tumors.
Accuracy and inter-observer variability of 3D versus 4D cone-beam CT based image-guidance in SBRT for lung tumors.
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DOI：
10.1186/1748-717x-7-81
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发表时间：
2012-06-08
期刊：
影响因子：
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通讯作者：
Guckenberger M
中科院分区：
文献类型：
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作者：
Sweeney RA;Seubert B;Stark S;Homann V;Müller G;Flentje M;Guckenberger M
旨在分析在肺部肿瘤立体定向放射治疗 (SBRT) 中使用 3D 或 4D 锥形束 CT (CBCT) 技术的图像引导 (IG) 的准确性和观察者间变异性。本研究的基础是连续 21 名接受图像引导 SBRT 治疗原发性和继发性肺部肿瘤的患者。呼吸相关的 4D-CT 和规划轮廓可作为所有 IG 技术的参考。三种 IG 技术由三名放射肿瘤科医生 (RO) 和三名放射治疗技术人员 (RTT) 独立执行。使用呼吸相关 4D-CBCT (IG-4D) 进行图像引导并自动配准计划 4D-CT 和验证 4D-CBCT 被认为是黄金标准。结果与使用 3D-CBCT 的两种 IG 技术进行比较：1）在 3D-CBCT（IG-ITV）中手动配准计划内部目标体积（ITV）轮廓和运动模糊肿瘤； 2）自动配准规划参考CT图像和验证3D-CBCT（IG-3D）。 3D-CBCT 和 4D-CBCT 图像的图像质量按 1-3 级评分，其中 1 为最佳质量，3 为最差质量，用于 IGRT 结果的视觉验证。与 4D-CBCT 相比，3D-CBCT 的图像质量得分明显较差：最差分数 3 分别出现在 19% 和 7.1% 的观测值中。基于 IG 的 4D-CBCT 和 3D-CBCT 之间的靶点定位存在显着差异：与 IG-4D 的参考相比，使用 IG-ITV 时肿瘤位置平均相差 1.9mm±0.9mm（3D 矢量），使用 IG-3D 时肿瘤位置平均相差 3.6mm±3.2mm；与 IG-3D 相比，IG-ITV 的结果明显更接近参考 IG-4D。随着肿瘤运动幅度的增大，4D-CBCT与3D-CBCT技术之间的差异显着增大；类似地，3D-CBCT 图像质量分数越差，差异越大。与 4D-CBCT 相比，SI 方向的观察者间变异性最大，而使用 3D-CBCT 的 IG 显着更大：0.6mm 与 1.5mm（一个标准差）。与三个 RTT 相比，三个 RO 之间的观察者间变异性没有差异。呼吸相关 4D-CBCT 通过在存在呼吸引起的目标运动的情况下更精确的目标定位以及减少观察者间的变异性来提高图像引导的准确性。
To analyze the accuracy and inter-observer variability of image-guidance (IG) using 3D or 4D cone-beam CT (CBCT) technology in stereotactic body radiotherapy (SBRT) for lung tumors. Twenty-one consecutive patients treated with image-guided SBRT for primary and secondary lung tumors were basis for this study. A respiration correlated 4D-CT and planning contours served as reference for all IG techniques. Three IG techniques were performed independently by three radiation oncologists (ROs) and three radiotherapy technicians (RTTs). Image-guidance using respiration correlated 4D-CBCT (IG-4D) with automatic registration of the planning 4D-CT and the verification 4D-CBCT was considered gold-standard. Results were compared with two IG techniques using 3D-CBCT: 1) manual registration of the planning internal target volume (ITV) contour and the motion blurred tumor in the 3D-CBCT (IG-ITV); 2) automatic registration of the planning reference CT image and the verification 3D-CBCT (IG-3D). Image quality of 3D-CBCT and 4D-CBCT images was scored on a scale of 1–3, with 1 being best and 3 being worst quality for visual verification of the IGRT results. Image quality was scored significantly worse for 3D-CBCT compared to 4D-CBCT: the worst score of 3 was given in 19 % and 7.1 % observations, respectively. Significant differences in target localization were observed between 4D-CBCT and 3D-CBCT based IG: compared to the reference of IG-4D, tumor positions differed by 1.9 mm ± 0.9 mm (3D vector) on average using IG-ITV and by 3.6 mm ± 3.2 mm using IG-3D; results of IG-ITV were significantly closer to the reference IG-4D compared to IG-3D. Differences between the 4D-CBCT and 3D-CBCT techniques increased significantly with larger motion amplitude of the tumor; analogously, differences increased with worse 3D-CBCT image quality scores. Inter-observer variability was largest in SI direction and was significantly larger in IG using 3D-CBCT compared to 4D-CBCT: 0.6 mm versus 1.5 mm (one standard deviation). Inter-observer variability was not different between the three ROs compared to the three RTTs. Respiration correlated 4D-CBCT improves the accuracy of image-guidance by more precise target localization in the presence of breathing induced target motion and by reduced inter-observer variability.