Biomedical Imaging and Image Processing Lab, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
Phys Med Biol. 2020 Sep 11;65(18):185002. doi: 10.1088/1361-6560/ab97e6.
In this paper, a nonuniform projection distribution (NUPD) CT method is proposed for the region-of-interest-specific examination in the solitary lung nodule follow-up application in order to reduce redundant x-ray projections exposed on normal tissues. The method exploits personal previous lung CT scan information to design a nonuniform x-ray projection modulation scheme where x-rays are sparsely modulated over the areas outside of the nodule in each projection view. The nonuniform projection modulation scheme could obstruct 71.84% of the x-ray projections within each scanning view in the case of a 40-mm-diameter region of interest of a solitary lung nodule, and eventually, 96.80% of the x-ray projections are eliminated in a complete circular scan in cooperation with the double sparse sampling protocol. We also devise a prior image-guided patchwise low-rank reconstruction in NUPD CT to improve the imaging quality. The proposed reconstructions have the highest Peak Signal to Noise Ratio values compared with other methods for both the full field of view (FOV) and region of interest (ROI). The structural similarities with the references are 0.9922 for the complete FOV and above 0.9999 for the ROI.
本文提出了一种非均匀投影分布（NUPD）CT 方法，用于孤立肺结节随访应用中的感兴趣区域特定检查，以减少对正常组织的冗余 X 射线投影。该方法利用个人先前的肺部 CT 扫描信息来设计一种非均匀 X 射线投影调制方案，其中在每个投影视图中，X 射线在结节外部区域稀疏调制。在直径为 40mm 的孤立肺结节的感兴趣区域中，非均匀投影调制方案可以阻止每个扫描视图中 71.84%的 X 射线投影，最终在与双稀疏采样协议配合下，消除 96.80%的 X 射线投影。我们还在 NUPD CT 中设计了一种基于先验图像引导的分片低秩重建，以提高成像质量。与其他方法相比，所提出的重建方法在全视野（FOV）和感兴趣区域（ROI）中均具有最高的峰值信噪比值。与参考的结构相似性分别为完整 FOV 的 0.9922 和 ROI 的 0.9999 以上。
