A novel reconstruction algorithm to extend the CT scan field-of-view
A novel reconstruction algorithm to extend the CT scan field-of-view
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DOI：
10.1118/1.1776673
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发表时间：
2004-09-01
期刊：
影响因子：
3.8
通讯作者：
Myers, TJ
中科院分区：
文献类型：
--
作者：
Hsieh, J;Chao, E;Myers, TJ
由于各种原因，在计算机断层扫描（CT）扫描仪上获得的投影数据集可能被截断。也就是说，被扫描物体的一部分位于扫描视场（SFOV）之外，并且不测量这些区域对应的线积分。投影截断问题会导致成像伪影，从而导致次优图像质量。在本文中，我们提出了一种能够充分估计SFOV外投影的重建算法。我们利用了这样一个事实，即在平行采样几何中每个理想投影的总衰减在视图上保持不变。我们使用截断位置投影样本的大小和斜率来估计最适合SFOV外投影数据的水柱。为了提高算法的鲁棒性，对拟合参数进行了连续性约束。进行了大量的幻影和患者实验来测试所提出算法的鲁棒性和准确性。(C) 2004年美国医学物理学家协会。
For various reasons, a projection dataset acquired on a computed tomography (CT) scanner can be truncated. That is, a portion of the scanned object is positioned outside the scan field-of-view (SFOV) and the line integrals corresponding to those regions are not measured. A projection truncation problem causes imaging artifacts that lead to suboptimal image quality. In this paper, we propose a reconstruction algorithm that enables an adequate estimation of the projection outside the SFOV. We make use of the fact that the total attenuation of each ideal projection in a parallel sampling geometry remains constant over views. We use the magnitudes and slopes of the projection samples at the location of truncation to estimate water cylinders that can best fit to the projection data outside the SFOV. To improve the robustness of the algorithm, continuity constraints are placed on the fitting parameters. Extensive phantom and patient experiments were conducted to test the robustness and accuracy of the proposed algorithm. (C) 2004 American Association of Physicists in Medicine.