Optical conductivity of triple point fermions.
Optical conductivity of triple point fermions.
复制标题
DOI：
10.1088/1361-648x/abd739
复制
发表时间：
2021-01-12
期刊：
影响因子：
--
通讯作者：
Jafari SA
中科院分区：
文献类型：
--
作者：
Habibi A;Farajollahpour T;Jafari SA
本研究的目的是量化短扫描轨迹下稀疏视图采集对专用锥形束乳房计算机断层扫描（BCT）图像质量测量的影响，与360度全扫描采集相比。从现有的临床研究数据库中选择30个钙化病灶的全扫描（360度；300视图）BCT检查的投影数据。以全扫描数据的FDK重建作为参考。选择了204度和270度两个短扫描轨迹对应的投影数据，对应于锥束BCT系统可实现的最小和最大角度范围。对投影数据进行回顾性采样，提供225、180和168个视图进行270度短扫描，170个视图进行204度短扫描。270度180和168视图的短扫描使用非均匀角度采样。采用快速、迭代、全变差正则化统计重建技术（FIRST）进行短扫描图像重建。图像质量通过方差、脂肪组织和纤维腺组织之间的信噪比（SDNR）、两个正交方向上钙化的半最大值全宽（FWHM）以及相对于参考全扫描FDK重建计算的偏差和均方根误差（RMSE）来量化。以全扫描FDK为参考计算的短扫描重建的偏置中值（8.6×10−4 - 10.3×10−4 cm−1）和RMSE （6.8×10−6 - 9.8×10−6 cm−1）接近但不为零（P<0.0001，单样本中位数检验）。短扫描重建中钙化的FWHM与参考FDK重建没有显著差异（P= 0.118），除了短扫描重建沿270度168个视图的上下方向（P=0.046）。与全扫描FDK重建相比，短扫描重建的方差和SDNR显著改善（P<0.0001）。本研究证明了基于短扫描、稀疏视图、压缩感知的迭代重建的可行性。这项研究表明，在不牺牲图像质量的情况下，缩短扫描时间和降低辐射剂量是潜在可行的。
The purpose of this study is to quantify the impact of sparse-view acquisition in short-scan trajectories, compared to 360-degrees full-scan acquisition, on image quality measures in dedicated cone-beam breast computed tomography (BCT). Projection data from 30 full-scan (360-degrees; 300 views) BCT exams with calcified lesions were selected from an existing clinical research database. Feldkamp-Davis-Kress (FDK) reconstruction of the full-scan data served as the reference. Projection data corresponding to two short-scan trajectories, 204 and 270-degrees, which correspond to the minimum and maximum angular range achievable in a cone-beam BCT system were selected. Projection data were retrospectively sampled to provide 225, 180, and 168 views for 270-degrees short-scan, and 170 views for 204-degrees short-scan. Short-scans with 180 and 168 views in 270-degrees used non-uniform angular sampling. A fast, iterative, total variation-regularized, statistical reconstruction technique (FIRST) was used for short-scan image reconstruction. Image quality was quantified by variance, signal-difference to noise ratio (SDNR) between adipose and fibroglandular tissues, full-width at half-maximum (FWHM) of calcifications in two orthogonal directions, as well as, bias and root-mean-squared-error (RMSE) computed with respect to the reference full-scan FDK reconstruction. The median values of bias (8.6×10−4 – 10.3×10−4 cm−1) and RMSE (6.8×10−6 – 9.8×10−6 cm−1) in the short-scan reconstructions, computed with the full-scan FDK as the reference were close to, but not zero (P<0.0001, one-sample median test). The FWHM of the calcifications in the short-scan reconstructions did not differ significantly from the reference FDK reconstruction (P>0.118), except along the superior-inferior direction for the short-scan reconstruction with 168 views in 270-degrees (P=0.046). The variance and SDNR from short-scan reconstructions were significantly improved compared to the full-scan FDK reconstruction (P<0.0001). This study demonstrates the feasibility of the short-scan, sparse-view, compressed sensing-based iterative reconstruction. This study indicates that shorter scan times and reduced radiation dose without sacrificing image quality are potentially feasible.