Reduction of motion artefacts in on-board cone beam CT by warping of projection images
Reduction of motion artefacts in on-board cone beam CT by warping of projection images
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DOI：
10.1259/bjr/90983944
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发表时间：
2011-03-01
影响因子：
2.6
通讯作者：
Moore, C. J.
中科院分区：
文献类型：
--
作者：
Marchant, T. E.;Price, G. J.;Moore, C. J.
目的：描述一种基于投影图像翘曲的平板成像锥束CT(CBCT)运动校正方法的开发和测试。方法：跟踪患者表面或内部的标记，并计算其平均三维位置。然后，在重建之前对二维(2D)锥束投影图像进行扭曲，以将每个标记从其平均3D位置放置在投影处。用变形虚拟体模的模拟锥束投影图像、运动乳房体模的真实CBCT图像以及1例乳腺癌和1例胰腺癌放射治疗患者的临床CBCT图像对运动校正方法进行了测试。结果：在体模研究中，该方法大大减少了放疗靶区局部的运动伪影，并能够准确地恢复真实的表面形状。90%的乳房体模运动补偿面与真实面的距离在1 mm以内，只有2%的点与真实面的距离大于2 mm。临床CBCT图像经运动校正后，放射治疗靶区局部图像质量有所改善。结论：该方法能有效地消除CBCT图像中的运动伪影。
Objective: We describe the development and testing of a motion correction method for flat panel imager-based cone beam CT (CBCT) based on warping of projection images.Methods: Markers within or on the surface of the patient were tracked and their mean three-dimensional (3D) position calculated. The two-dimensional (2D) cone beam projection images were then warped before reconstruction to place each marker at the projection from its mean 3D position. The motion correction method was tested using simulated cone beam projection images of a deforming virtual phantom, real CBCT images of a moving breast phantom and clinical CBCT images of a patient with breast cancer and another with pancreatic cancer undergoing radiotherapy.Results: In phantom studies, the method was shown to greatly reduce motion artefacts in the locality of the radiotherapy target and allowed the true surface shape to be accurately recovered. The breast phantom motion-compensated surface was within 1 mm of the true surface shape for 90% of surface points and greater than 2 mm from the true surface at only 2% of points. Clinical CBCT images showed improved image quality in the locality of the radiotherapy target after motion correction.Conclusion: The proposed method is effective in reducing motion artefacts in CBCT images.