A FAST PROJECTOR-BACKPROJECTOR PAIR MODELING THE ASYMMETRIC, SPATIALLY VARYING SCATTER RESPONSE FUNCTION FOR SCATTER COMPENSATION IN SPECT IMAGING
A FAST PROJECTOR-BACKPROJECTOR PAIR MODELING THE ASYMMETRIC, SPATIALLY VARYING SCATTER RESPONSE FUNCTION FOR SCATTER COMPENSATION IN SPECT IMAGING
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DOI：
10.1109/23.256735
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发表时间：
1993-08-01
影响因子：
1.8
通讯作者：
TSUI, BMW
中科院分区：
文献类型：
--
作者：
FREY, EC;JU, ZW;TSUI, BMW
我们之前已经开发了一种方法，平板衍生散射估计（SDSE），用于快速准确地模拟非对称的，空间变化的散射响应函数，均匀衰减的凸表面物体。该模型已在投影-背射器中实现，当与迭代重建技术相结合时，可在单光子发射计算机断层扫描（SPECT）中提供精确的散射补偿。这些基于迭代重建的散射补偿技术的优点是它们利用了所有检测到的光子，避免了基于减法的方案产生的噪声放大。此外，迭代重建散射补偿不涉及使用任意可调参数。在本文中，我们提出了一种新的快速实现SDSE的算法，与直接实现相比，它将计算时间减少了16倍。用新算法计算的投影数据与蒙特卡罗模拟的结果比较好。当与更快的计算机和快速收敛的迭代重建算法相结合时，这种快速投影-反向投影对使得基于迭代重建的散射补偿成为可能。
We have previously developed a method, slab derived scatter estimation (SDSE), for quickly and accurately modeling the asymmetric, spatially varying scatter response function in uniformly attenuating objects with convex surfaces. This model has been implemented in a projector-backprojector that, when combined with iterative reconstruction techniques, provides accurate scatter compensation in single-photon emission computed tomography (SPECT). These iterative reconstruction based scatter compensation techniques have the advantage that they use all detected photons, avoiding the noise amplification occurring with subtraction based schemes. In addition, scatter compensation with iterative reconstruction does not involve the use of arbitrary adjustable parameters. In this paper we present a new fast algorithm for implementing SDSE that reduces computation time by a factor of 16 compared to a direct implementation. Projection data computed with the new algorithm compare well with that from Monte Carlo simulations. When combined with faster computers and iterative reconstruction algorithms that converge rapidly, this fast projector-backprojector pair makes iterative reconstruction based scatter compensation feasible.