近年来， Katsevich提出一种基于滤波反投影的螺旋锥束CT重建算法，并给出相应的重建公式改进形式，可以有效地解决长物体成像问题。基于Katsevich算法框架，提出了新的螺旋锥束CT精确重建算法。该算法利用数学上严格的推导，将Katseivch重建公式中关于旋转角度的微分运算完全回避，使得成像质量得到较大改善，减少了重建伪影。同时，新算法仍然基于平移不变滤波且数据冗余加权在滤波过程之后进行，保持了数值计算的灵活性。为验证本文算法的有效性，对计算机模拟数据进行仿真实验，实验结果表明，新重建算法的重建图像质量较Katsevich重建算法有较大提高。

Recently,Katsevich proposed an exact FBP algorithm and its improved version for image reconstruction in helical cone beam CT. In this paper,we present a new FBP image reconstruction algorithm based on the Katsevich’s original algorithm paradigm. This proposed algorithm can achieve good image quality improvement and fewer artifacts since it successfully avoids the direct derivatives with respect to rotation angle,The new algorithm still performs a 1D shift invariant filtering of the modified data on the detector plane and the redundancy weight is applied after filtering,allowing a more efficient numerical implementation. Results in these studies confirm the observation that the proposed algorithm can improve the image resolution over Katsevich’s original algorithm with noiseless and noise projection data.