一种快速的光栅相衬层析成像方法（英文）

A Fast Imaging Method for Grating-based X-ray Phase-contrast Tomosynthesis

数字X光层析成像由于其低辐射剂量和增强的图像对比度,广泛应用于医学诊断中。结合X光相衬成像的优异的软组织成像能力,X光相衬层析成像方法可以获得更好的软组织成像能力。本文的目的是提出一种快速的、低辐射剂量的X光相衬层析成像方法及算法。本方法在数据采集过程中光栅的位移和样品的旋转同时进行,它区别于传统的相位步进方法,采集到的数据是不完全的。我们提出了一种新型的重建方法,即内聚焦式重建。实验验证了提出的快速光栅相衬层析成像方法,结果表明在同等辐射剂量情况下,快速光栅相衬层析成像优于传统的基于相位步进的方法。由于快速光栅相衬层析成像采用连续的物体转动和光栅移动,其成像速度更快,避免了潜在的运动伪影。

As an imaging technique with low radiation dose and improved contrast, digital X-ray tomosynthesis is widely used in clinical diagnoses. Based on the superior capability of X-ray phase-contrast imaging（PCI） techniques for imaging low density materials, the combination of X-ray tomosynthesis and PCI could potentially provide higher efficiency in the detection of soft tissues. The goal of this work was to develop a fast and low-dose imaging method for phase-contrast tomosynthesis, called grating-based phase-contrast tomosynthesis（GPC-Tomo）, which integrates tomosynthesis with a grating-based PCI technique. During data acquisition with the proposed fast GPC-Tomo, the grating scanning and sample rotation occur at the same time, which is different from the scheme used for conventional GPC-Tomo. Without the phase stepping（PS） technique to extract the differential phase-contrast image at each projection angle for the conventional GPC-Tomo, the data collected by the fast GPC-Tomo is incomplete. Here, we propose a novel reconstruction method called inner-focusing（IF） reconstruction for the proposed fast GPC-Tomo. In the reconstruction stage, measured X-ray intensities from neighboring projection angles that pass through the reconstructed point are utilized to compose a stepping period for signal extraction. The proposed fast GPC-Tomo technique was validated by real experiments. The results demonstrated that the reconstructed images acquired with the fast GPC-Tomo are better than those acquired with conventional GPC-Tomo, and with near-equivalence in radiation dose. Furthermore, since the proposed fast GPC-Tomo employs continuous rotation, its scanning time is much less than the stop-and-go motion of the conventional GPC-Tomo.（School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China）