A short-scan reconstruction for cone-beam CT using shift-invariant FBP and equal weighting.
A short-scan reconstruction for cone-beam CT using shift-invariant FBP and equal weighting.
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DOI：
10.1118/1.2789405
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发表时间：
2007-11
期刊：
影响因子：
3.8
通讯作者：
Lei Zhu;Sungwon Yoon;R. Fahrig
中科院分区：
文献类型：
--
作者：
Lei Zhu;Sungwon Yoon;R. Fahrig
利用ID移不变滤波、圆锥波束反向投影和等加权，推导了圆锥波束短扫描的三维重建公式。首先将发散投影转化为平行投影，利用经典的中心切片定理对圆形CB数据进行分析。研究了傅里叶空间的采样密度，利用反投影前的一维移不变滤波来补偿非均匀性。最后的公式由传统的FDK重建和利用微分反投影和图像域的一维希尔伯特变换的校正项组成。在全扫描时，该方法简化为FDK算法，而对于短扫描，CB伪影被第二项抑制。计算机仿真和实验结果表明，该算法优于带有Parker加权的改进FDK算法。该算法采用平移不变滤波后投影结构，实现效率高，且只需对FDK算法进行简单的修改。
A 3D reconstruction formula has been derived for a circular cone-beam (CB) short scan using ID shift-invariant filtering, CB backprojection, and equal weighting. By first converting the divergent projections to parallel projections, we analyze the circular CB data using the classic central slice theorem. The sampling density in Fourier space is investigated and 1D shift-invariant filtering before backprojection can be used to compensate for the nonuniformity. The final formula consists of a conventional FDK reconstruction and a correction term using differential backprojection and the 1D Hilbert transform in the image domain. On a full scan, the approach reduces to the FDK algorithm, while for a short scan, the CB artifacts are suppressed by the second term. This algorithm outperforms the modified FDK algorithm with Parker's weighting, as illustrated by computer simulations and experimental results. Due to its shift-invariant filtered-backprojection structure, the proposed algorithm is implemented efficiently, and requires a simple adaptation of the FDK algorithm.