Implementation and evaluation of an end-to-end IGRT test.
Implementation and evaluation of an end-to-end IGRT test.
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DOI：
10.1120/jacmp.v13i5.3939
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发表时间：
2012-09-06
影响因子：
2.1
通讯作者：
Childress NL
中科院分区：
文献类型：
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作者：
Kry SF;Jones J;Childress NL
本工作的目标是开发和评价端到端测试，以确定和验证图像引导放射治疗设置相对于辐射等中心的准确性。这是通过将一个带有中心钨球的立方体体模直接放置在治疗床上完成的，并在纵向、横向和垂直维度上偏离等中心点5.0 mm或随机量。采集高分辨率锥形束CT图像，并与参考CT图像中的钨球对齐。根据该对准移动扫描床，并使用电子射野成像设备采集兆伏前后位和侧位图像。辐射等中心（基于MV场）和球体中心（即，基于kV成像的对准点）通过Winston-Lutz分析确定每个图像。该程序重复10次以确定短期重现性，然后在临床环境中每天重复51天。短期再现性试验得出基于成像的等中心和辐射等中心之间的平均3D向量位移，最大位移为1.1 mm。临床再现性试验得出的平均位移为，当立方体偏移5.0 mm时，最大位移为2.0 mm。当立方体偏移随机量时，平均位移最大为1.8mm。在所有方向上观察到这些差异，并且与治疗床移位的幅度无关。该测试在临床上快速且易于实施，并突出显示了图像引导放射治疗环境中的设置不准确性。PACS编号：87.55.km; 87.55.Qr; 87.56.Fc
The goal of this work was to develop and evaluate an end‐to‐end test for determining and verifying image‐guided radiation therapy setup accuracy relative to the radiation isocenter. This was done by placing a cube phantom with a central tungsten sphere directly on the treatment table and offset from isocenter either by 5.0 mm in the longitudinal, lateral, and vertical dimensions or by a random amount. A high‐resolution cone‐beam CT image was acquired and aligned with the tungsten sphere in the reference CT image. The table was shifted per this alignment, and megavoltage anterior–posterior and lateral images were acquired with the electronic portal imaging device. Agreement between the radiation isocenter (based on the MV field) and the center of the sphere (i.e., the alignment point based on kV imaging) was determined for each image via Winston‐Lutz analysis. This procedure was repeated 10 times to determine short‐term reproducibility, and then repeated daily for 51 days in a clinical setting. The short‐term reproducibility test yielded a mean 3D vector displacement of between the imaging‐based isocenter and the radiation isocenter, with a maximum displacement of 1.1 mm. The clinical reproducibility test yielded a mean displacement of with a maximum of 2.0 mm when the cube was offset by 5.0 mm, and a mean displacement of with a maximum of 1.8 mm when the cube was offset by a random amount. These differences were observed in all directions and were independent of the magnitude of the couch shift. This test was quick and easy to implement clinically and highlighted setup inaccuracies in an image‐guided radiation therapy environment. PACS numbers: 87.55.km; 87.55.Qr; 87.56.Fc