Efficient 3-D TOF PET reconstruction using view-grouped histo-images: DIRECT-direct image reconstruction for TOF.
Efficient 3-D TOF PET reconstruction using view-grouped histo-images: DIRECT-direct image reconstruction for TOF.
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DOI：
10.1109/tmi.2008.2012034
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发表时间：
2009-05
影响因子：
10.6
通讯作者：
Karp JS
中科院分区：
文献类型：
--
作者：
Matej S;Surti S;Jayanthi S;Daube-Witherspoon ME;Lewitt RM;Karp JS
对于现代飞行时间PET系统，其中可能的响应线和TOF箱的数量远大于采集事件的数量，最合适的重建方法被认为是列表模式方法。然而，它们的缺点是重建和灵敏度矩阵计算的计算成本相对较高。所提出的DIRECT方法内的TOF数据的有效处理通过以下方式获得：1）将TOF事件按角度（方位角和共极）分组到由TOF分辨率的角度采样要求给出的一组视图，以及2）将这些分组的事件和校正数据沉积（加权直方图）到一组“组织图像”中，每个视图一个组织图像。组织图像具有与重建图像相同的几何结构（体素网格、大小和方向）。该概念类似于涉及将T0 F数据分箱到在T0 F方向上扩展的角度子采样的组织投影投影中的方法。然而，与合并到组织投影中不同，将TOF事件直接沉积到图像体素中消除了在重建期间对跟踪和/或插值操作的需要。连同直接在图像空间中的重建操作的性能，这导致TOF重建算法的非常有效的实现。此外，分辨率属性也不会受到损害，因为事件从一开始就被放置到期望大小的图像元素中。在这项工作中，通过使用直接的方法结合行动作最大似然法（RAMLA）算法的概念和效率的建议的数据分区方案证明。
For modern Time-Of-Flight PET systems, in which the number of possible lines of response and TOF bins is much larger than the number of acquired events, the most appropriate reconstruction approaches are considered to be list-mode methods. However, their shortcomings are relatively high computational costs for reconstruction and for sensitivity matrix calculation. Efficient treatment of TOF data within the proposed DIRECT approach is obtained by 1) angular (azimuthal and co-polar) grouping of TOF events to a set of views as given by the angular sampling requirements for the TOF resolution, and 2) deposition (weighted-histogramming) of these grouped events, and correction data, into a set of “histo-images”, one histo-image per view. The histo-images have the same geometry (voxel grid, size and orientation) as the reconstructed image. The concept is similar to the approach involving binning of the TOF data into angularly sub-sampled histo-projections -projections expanded in the TOF directions. However, unlike binning into histo-projections, the deposition of TOF events directly into the image voxels eliminates the need for tracing and/or interpolation operations during the reconstruction. Together with the performance of reconstruction operations directly in image space, this leads to a very efficient implementation of TOF reconstruction algorithms. Furthermore, the resolution properties are not compromised either, since events are placed into the image elements of the desired size from the beginning. Concepts and efficiency of the proposed data partitioning scheme are demonstrated in this work by using the DIRECT approach in conjunction with the Row-Action Maximum-Likelihood (RAMLA) algorithm.