Line plus arc source trajectories and their R-line coverage for long-object cone-beam imaging with a C-arm system.
Line plus arc source trajectories and their R-line coverage for long-object cone-beam imaging with a C-arm system.
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DOI：
10.1088/0031-9155/56/12/001
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发表时间：
2011-06-21
影响因子：
3.5
通讯作者：
Noo F
中科院分区：
文献类型：
--
作者：
Yu Z;Wunderlich A;Dennerlein F;Lauritsch G;Noo F
C型臂系统的锥形束成像已成为介入放射学中的一种有价值的工具。目前，使用简单的圆形轨迹，但未来的应用应使用更复杂的源轨迹，不仅要避免锥束伪影，而且要允许扩展体积成像。实现这两个目标的一个有吸引力的策略是使用由线段连接的两个平行圆弧组成的源轨迹，可能具有重复。在这项工作中，我们解决了这样的轨迹的R线覆盖的问题。更具体地说，我们研究在何种程度上R-线这样的轨迹覆盖一个中心的圆柱形区域的兴趣（ROI）。R线是连接源轨迹上任意两点的线段。R线覆盖的知识是至关重要的，因为从轴向截断的数据的理论上精确和稳定的图像重建的一般理论仅为位于R线上的扫描对象中的点所知。我们的分析首先检查R线覆盖的元素轨迹组成的（i）两个平行的圆弧，（ii）圆弧正交连接到一条线段。接下来，我们利用我们对上述基本轨迹的R线的理解来确定由紧拟合线段连接的两个平行圆弧组成的轨迹的R线覆盖。对于该轨迹，我们发现R线覆盖不足以完全覆盖任何中心ROI。由于延长线段以外的圆弧有助于增加R线的覆盖范围，我们随后提出了一个轨迹由两个平行的圆弧连接的延长线。我们表明，该轨迹的R线可以完全覆盖中央ROI，如果线延伸足够长。我们的演示文稿包括一个公式的最小线扩展需要实现完整的R线覆盖的ROI与指定的大小，还包括一个初步研究所需的探测器的大小，表明R线添加的线扩展是没有约束。
Cone-beam imaging with C-arm systems has become a valuable tool in interventional radiology. Currently, a simple circular trajectory is used, but future applications should use more sophisticated source trajectories, not only to avoid cone-beam artifacts but also to allow extended volume imaging. One attractive strategy to achieve these two goals is to use a source trajectory that consists of two parallel circular arcs connected by a line segment, possibly with repetition. In this work, we address the question of R-line coverage for such a trajectory. More specifically, we examine to what extent R-lines for such a trajectory cover a central cylindrical region of interest (ROI). An R-line is a line segment connecting any two points on the source trajectory. Knowledge of R-line coverage is crucial because a general theory for theoretically exact and stable image reconstruction from axially-truncated data is only known for the points in the scanned object that lie on R-lines. Our analysis starts by examining the R-line coverage for the elemental trajectories consisting of (i) two parallel circular arcs, and (ii) a circular arc connected orthogonally to a line segment. Next, we utilize our understanding of the R-lines for the aforementioned elemental trajectories to determine the R-line coverage for the trajectory consisting of two parallel circular arcs connected by a tightly-fit line segment. For this trajectory, we find that the R-line coverage is insufficient to completely cover any central ROI. Because extension of the line segment beyond the circular arcs helps to increase the R-line coverage, we subsequently propose a trajectory composed of two parallel circular arcs connected by an extended line. We show that the R-lines for this trajectory can fully cover a central ROI if the line extension is long enough. Our presentation includes a formula for the minimum line extension needed to achieve full R-line coverage of an ROI with a specified size, and also includes a preliminary study on the required detector size, showing that the R-lines added by the line extension are not constraining.
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影响因子：
3.5
作者：
Katsevich, A
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Katsevich, A
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