List-mode-based reconstruction for respiratory motion correction in PET using non-rigid body transformations
List-mode-based reconstruction for respiratory motion correction in PET using non-rigid body transformations
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DOI：
10.1088/0031-9155/52/17/006
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发表时间：
2007-09-07
影响因子：
3.5
通讯作者：
Visvikis, D.
中科院分区：
文献类型：
--
作者：
Lamare, F.;Carbayo, M. J. Ledesma;Visvikis, D.
发射断层扫描中的呼吸运动导致图像质量下降。开发的校正方法一直集中在使用呼吸同步采集导致门控帧。但是，由于减少了统计量，这种帧具有较低的信噪比。在这项工作中，我们描述了在基于列表模式的重建中实现弹性变换，用于校正胸部呼吸运动，允许在呼吸运动平均采集过程中使用所有可用数据。使用在整个呼吸周期的不同点产生的NCAT幻像数据集对开发的算法进行评估。随后，通过将NCAT数据集与蒙特卡罗模拟相结合，生成了基于列表模式数据的pet模拟帧。利用NCAT动态CT图像，采用基于b样条基函数的非刚性配准算法，推导出考虑呼吸运动的变换参数。导出的位移矩阵随后应用于原始发射表模式数据的图像重建。开发并评估了在单遍列表模式EM （OPL-EM）算法中引入弹性变换的两种不同实现。校正后的图像与重建前使用列表模式数据的仿射变换产生的图像以及未校正的呼吸运动平均图像进行比较。结果表明，尽管考虑的两种校正技术在计算肺场的呼吸运动伪影方面都有显着改善，但基于弹性变换的校正在不同病变大小和位置的肺中导致更均匀的改善。
Respiratory motion in emission tomography leads to reduced image quality. Developed correction methodology has been concentrating on the use of respiratory synchronized acquisitions leading to gated frames. Such frames, however, are of low signal-to-noise ratio as a result of containing reduced statistics. In this work, we describe the implementation of an elastic transformation within a list-mode-based reconstruction for the correction of respiratory motion over the thorax, allowing the use of all data available throughout a respiratory motion average acquisition. The developed algorithm was evaluated using datasets of the NCAT phantom generated at different points throughout the respiratory cycle. List-mode-data-based PET-simulated frames were subsequently produced by combining the NCAT datasets with Monte Carlo simulation. A non-rigid registration algorithm based on B-spline basis functions was employed to derive transformation parameters accounting for the respiratory motion using the NCAT dynamic CT images. The displacement matrices derived were subsequently applied during the image reconstruction of the original emission list mode data. Two different implementations for the incorporation of the elastic transformations within the one-pass list mode EM (OPL-EM) algorithm were developed and evaluated. The corrected images were compared with those produced using an affine transformation of list mode data prior to reconstruction, as well as with uncorrected respiratory motion average images. Results demonstrate that although both correction techniques considered lead to significant improvements in accounting for respiratory motion artefacts in the lung fields, the elastic-transformation-based correction leads to a more uniform improvement across the lungs for different lesion sizes and locations.