Prior image constrained scatter correction in cone-beam computed tomography image-guided radiation therapy.
Prior image constrained scatter correction in cone-beam computed tomography image-guided radiation therapy.
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DOI：
10.1088/0031-9155/56/4/009
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发表时间：
2011-02-21
影响因子：
3.5
通讯作者：
Chen GH
中科院分区：
文献类型：
--
作者：
Brunner S;Nett BE;Tolakanahalli R;Chen GH
当使用较厚的物体和较大的锥角时，X射线散射是锥束计算机断层扫描中的一个重要问题，因为散射辐射可能导致对比度降低和CT数不准确。通过将高质量的先验图像结合到图像重建过程中，在X射线计算机断层摄影（CT）中已经取得了进展。在本文中，我们扩展了这一想法，以纠正散射引起的阴影伪影锥束CT图像引导放射治疗。具体来说，本文提出了一种新的散射校正算法，它使用一个低散射伪影的先验图像，以减少阴影伪影在高散射条件下采集的锥束CT图像。所提出的校正算法开始于一个经验假设，即目标图像可以被写为一系列基础图像的加权和，这些基础图像是通过将原始锥束投影数据提高到不同的功率而生成的，然后，使用标准的滤波反投影算法进行重建。通过最小化目标图像和先前图像之间的差异来计算每个基础图像的权重。通过使用配备机载成像仪的Varian 2100 EX系统进行体模研究，对散射校正算法的性能进行定性和定量评价。结果表明，所提出的散射校正算法使用具有低散射伪影的先验图像，可以在全扇和半扇模式下显著减轻散射引起的阴影伪影。
X-ray scatter is a significant problem in cone-beam computed tomography when thicker objects and larger cone angles are used, as scattered radiation can lead to reduced contrast and CT number inaccuracy. Advances have been made in x-ray computed tomography (CT) by incorporating a high quality prior image into the image reconstruction process. In this paper, we extend this idea to correct scatter-induced shading artifacts in cone-beam CT image-guided radiation therapy. Specifically, this paper presents a new scatter correction algorithm which uses a prior image with low scatter artifacts to reduce shading artifacts in cone-beam CT images acquired under conditions of high scatter. The proposed correction algorithm begins with an empirical hypothesis that the target image can be written as a weighted summation of a series of basis images that are generated by raising the raw cone-beam projection data to different powers, and then, reconstructing using the standard filtered backprojection algorithm. The weight for each basis image is calculated by minimizing the difference between the target image and the prior image. The performance of the scatter correction algorithm is qualitatively and quantitatively evaluated through phantom studies using a Varian 2100 EX System with an on-board imager. Results show that the proposed scatter correction algorithm using a prior image with low scatter artifacts can substantially mitigate scatter-induced shading artifacts in both full-fan and half-fan modes.
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影响因子：
3.5
作者：
Poludniowski, G.;Evans, P. M.;Webb, S.
通讯作者：
Webb, S.
DOI：
10.1016/j.jvir.2008.02.002
发表时间：
2008-06-01
影响因子：
2.9
作者：
Orth, Robert C.;Wallace, Michael J.;Kuo, Michael D.
通讯作者：
Kuo, Michael D.
影响因子：
--
作者：
Khoury, A.;Siewerdsen, J. H.;Jaffray, D. A.
通讯作者：
Jaffray, D. A.
影响因子：
3.8
作者：
Khoury, Amal;Whyne, Cari M.;Jaffray, David
通讯作者：
Jaffray, David
影响因子：
3.5
作者：
Kyriakou, Yiannis;Kalender, Willi
通讯作者：
Kalender, Willi