Relaxed ordered subset preconditioned alternating projection algorithm for PET reconstruction with automated penalty weight selection.
Relaxed ordered subset preconditioned alternating projection algorithm for PET reconstruction with automated penalty weight selection.
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用于具有自动惩罚权重选择的 PET 重建的宽松有序子集预条件交替投影算法
DOI：
10.1002/mp.12292
复制
发表时间：
2017-08
期刊：
影响因子：
3.8
通讯作者：
Xu Y
中科院分区：
文献类型：
--
作者：
Ross Schmidtlein C;Lin Y;Li S;Krol A;Beattie BJ;Humm JL;Xu Y
在正电子发射断层扫描（PET）中，研究了基于松弛有序子集（ROS）和非光滑罚函数的预条件交替投影算法（PAPA）的性能。采用高阶全变差（HOTV）正则化器，并提出了一种基于实测数据的惩罚权值无监督选择方法。开发并实现了用于PET图像重建的具有HOTV罚分的ROS版本PAPA（ROS-HOTV-PAPA）。使用两个合成体模（几何体模和脑体模）模拟二维PET数据，其几何结构类似于GE D 690/710 PET/CT，具有均匀衰减、真实散射（25%）和随机（25%）。使用ROS-HOTV-PAPA重建了三个计数水平（高/中/低），对应于每个支持体素的平均信息密度125、25和5噪声等效计数（NEC）。患者的脑部和全身PET数据在GE D 690 PET/CT上以相似的时间间隔采集，并使用ROS-HOTV-PAPA和可用的临床有序子集期望最大化（OSEM）算法进行重建。半经验地推导出惩罚权重对的幂律模型。它的参数从数据中得到阐明，并用于在缩小的搜索空间内无监督地选择惩罚权重。定性评价所得图像质量，包括减少阶梯伪影、图像噪声、空间分辨率和对比度，并使用均方根误差（RMSE）作为全局度量进行定量评价。并对收敛速度进行了研究。与非ROS-HOTV-PAPA相比，ROS-HOTV-PAPA快速收敛，没有极限环行为的证据。重建的图像质量上级最佳后滤波OSEM重建的噪声，空间分辨率和对比度。没有观察到楼梯伪影。与优化OSEM相比，使用ROS-HOTV-PAPA重建的测量体模图像显示RMSE降低5 - 44%。最大的改善发生在最低计数图像中。此外，ROS-HOTV-PAPA重建产生的图像与RMSE类似于使用最佳后滤波OSEM重建的图像，但在NEC的四分之一。使用ROS实现HOTV-PAPA的加速。这伴随着改进的RMSE度量和感知图像质量，两者都上级临床或优化OSEM获得的。与目前的临床实践相比，这可以使PET研究中患者的辐射剂量减少多达四倍。所提出的无监督参数选择方法为所选体模和患者的PET研究提供了有用的惩罚权重估计。总之，本研究的结果表明，ROS-HOTV-PAPA是临床应用的合适候选者，值得进一步研究。
Performance of the preconditioned alternating projection algorithm (PAPA) using relaxed ordered subsets (ROS) with a non-smooth penalty function was investigated in positron emission tomography (PET). A higher order total variation (HOTV) regularizer was applied and a method for unsupervised selection of penalty weights based on the measured data is introduced. A ROS version of PAPA with HOTV penalty (ROS-HOTV-PAPA) for PET image reconstruction was developed and implemented. Two-dimensional PET data were simulated using two synthetic phantoms (geometric and brain) in geometry similar to GE D690/710 PET/CT with uniform attenuation, and realistic scatter (25%) and randoms (25%). Three count levels (high/medium/low) corresponding to mean information densities of 125, 25, and 5 noise equivalent counts (NEC) per support voxel were reconstructed using ROS-HOTV-PAPA. The patients’ brain and whole body PET data were acquired at similar on GE D690 PET/CT with time-of-fight and were reconstructed using ROS-HOTV-PAPA and available clinical ordered-subset expectation-maximization (OSEM) algorithms. A power-law model of the penalty weights’ dependence on was semi-empirically derived. Its parameters were elucidated from the data and used for unsupervised selection of the penalty weights within a reduced search space. The resulting image quality was evaluated qualitatively, including reduction of staircase artifacts, image noise, spatial resolution and contrast, and quantitatively using root mean squared error (RMSE) as a global metric. The convergence rates were also investigated. ROS-HOTV-PAPA converged rapidly, in comparison to non-ROS-HOTV-PAPA, with no evidence of limit cycle behavior. The reconstructed image quality was superior to optimally post-filtered OSEM reconstruction in terms of noise, spatial resolution, and contrast. Staircase artifacts were not observed. Images of the measured phantom reconstructed using ROS-HOTV-PAPA showed reductions in RMSE of 5 – 44% as compared with optimized OSEM. The greatest improvement occurred in the lowest count images. Further, ROS-HOTV-PAPA reconstructions produced images with RMSE similar to images reconstructed using optimally post-filtered OSEM but at one-quarter the NEC. Acceleration of HOTV-PAPA was achieved using ROS. This was accompanied by an improved RMSE metric and perceptual image quality that were both superior to that obtained with either clinical or optimized OSEM. This may allow up to a four-fold reduction of the radiation dose to the patients in a PET study, as compared with current clinical practice. The proposed unsupervised parameter selection method provided useful estimates of the penalty weights for the selected phantoms’ and patients’ PET studies. In sum, the outcomes of this research indicate that ROS-HOTV-PAPA is an appropriate candidate for clinical applications and warrants further research.
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DOI：
10.1016/j.ejmp.2015.07.139
发表时间：
2015-12
期刊：
Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)
影响因子：
--
作者：
Berthon B;Häggström I;Apte A;Beattie BJ;Kirov AS;Humm JL;Marshall C;Spezi E;Larsson A;Schmidtlein CR
通讯作者：
Schmidtlein CR
用于最大后验 ECT 重建的预处理交替投影算法
影响因子：
2.1
作者：
Krol A;Li S;Shen L;Xu Y
通讯作者：
Xu Y
DOI：
10.1073/pnas.90.21.9758
发表时间：
1993-11-01
影响因子：
11.1
作者：
BARRETT, HH;YAO, J;MYERS, KJ
通讯作者：
MYERS, KJ
影响因子：
5.4
作者：
Eldar, Yonina C.
通讯作者：
Eldar, Yonina C.
影响因子：
3.1
作者：
Chan, T;Marquina, A;Mulet, P
通讯作者：
Mulet, P