A filtered backprojection algorithm with ray-by-ray noise weighting
A filtered backprojection algorithm with ray-by-ray noise weighting
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DOI：
10.1118/1.4790696
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发表时间：
2013-03-01
期刊：
影响因子：
3.8
通讯作者：
Zamyatin, Alex
中科院分区：
文献类型：
--
作者：
Zeng, Gengsheng L.;Zamyatin, Alex
目的：在我们最近提出的逐视加权滤波反投影(RFBP)算法的基础上，推导出一种逐射线加权滤波反投影(RFBP)算法。投影数据可以与它们的噪声方差成反比地加权。此外，为了进一步降低噪声，本文还提出了一种保持边缘的双边滤波方法进行后置滤波。基于Feldkamp算法对圆轨道锥束几何进行了实现。结果：通过计算机仿真和临床身体数据进行了图像重建，验证了该算法的有效性和可行性。新的FBP算法能够显著降低或去除噪声纹理，这是传统的FBP算法所不能做到的。该算法的计算时间与传统的FBP算法基本相同。结论：在FBP算法中引入了一种基于射线的噪声加权方案。这种新的FBP型算法显著地减少或消除了低剂量CT中的条纹伪影。(C)2013年美国医学物理学家协会。
Purpose: This paper derives a ray-by-ray weighted filtered backprojection (rFBP) algorithm, based on our recently developed view-by-view weighted, filtered backprojection (vFBP) algorithm.Methods: The rFBP algorithm directly extends the vFBP algorithm by letting the noise weighting vary from channel to channel within each view. The projection data can be weighted in inverse proportion to their noise variances. Also, an edge-preserving bilateral filter is suggested to perform post filtering to further reduce the noise. The proposed algorithm has been implemented for the circular-orbit cone-beam geometry based on Feldkamp's algorithm.Results: Image reconstructions with computer simulations and clinical cadaver data are presented to illustrate the effectiveness and feasibility of the proposed algorithm. The new FBP-type algorithm is able to significantly reduce or remove the noise texture, which the conventional FBP is unable to do. The computation time of the proposed rFBP algorithm is approximately the same as the conventional FBP algorithm.Conclusions: A ray-based noise-weighting scheme is introduced to the FBP algorithm. This new FBP-type algorithm significantly reduces or removes the streaking artifacts in low-dose CT. (C) 2013 American Association of Physicists in Medicine.