Digital tomosynthesis for verifying spine position during radiotherapy: a phantom study
Digital tomosynthesis for verifying spine position during radiotherapy: a phantom study
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DOI：
10.1088/0031-9155/58/16/5717
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发表时间：
2013-08-21
影响因子：
3.5
通讯作者：
Verbakel, Wilko F. A. R.
中科院分区：
文献类型：
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作者：
Gurney-Champion, Oliver J.;Dahele, Max;Verbakel, Wilko F. A. R.
在脊柱立体定向全身放射治疗(SBRT)等高精度放射治疗中，监测患者体位的稳定性是必不可少的。我们使用非临床的数字断层合成(DTS)软件和包含骨样脊柱结构的拟人骨盆模型，评估了数字断层合成(DTS)和三角测量的组合用于脊柱位置检测。用千伏锥束CT投影图像在门架旋转2~16度时生成单层DTS图像。将每个DTS切片配准到从计划CT扫描获得的数字重建DTS，以确定实际体模和治疗计划位置之间的2D移位。对相距4-22度的两个或更多个DTS配准进行三角测量，以确定3D模型位置。利用顺序生成的DTS图像，可以在较小的DTS延迟和三角角的情况下，每度更新一次模型位置。研究了DTS和三角测量角度对定位精度的影响。为了模拟脊柱SBRT的场景，测试了千伏图像采集过程中对兆伏辐射传输标准偏差的影响。此外，针对千伏图像采集过程中的各种微小的突然和渐变的运动，研究了该系统对不同运动类型的检测能力。
Monitoring the stability of patient position is essential during high-precision radiotherapy such as spine stereotactic body radiotherapy (SBRT). We evaluated the combination of digital tomosynthesis (DTS) and triangulation for spine position detection, using non-clinical DTS software and an anthropomorphic pelvic phantom that includes a bone-like spine structure. Kilovoltage cone beam CT projection images over 2-16 degrees gantry rotation were used to generate single slice DTS images. Each DTS slice was registered to a digitally reconstructed DTS derived from the planning CT scan to determine 2D shifts between actual phantom and treatment plan position. Two or more DTS registrations, central axes 4-22 degrees apart, were triangulated to determine the 3D phantom position. Using sequentially generated DTS images, the phantom position can be updated every degree with a small latency of DTS and triangulation angle. The precision of position determination was investigated as function of DTS and triangulation angle. To mimic the scenario of spine SBRT, the effect on the standard deviation of megavoltage radiation delivery during kV image acquisition was tested. In addition, the ability of the system to detect different types of movement was investigated for a variety of small sudden and gradual movements during kV image acquisition.