Brun Francesco, Brombal Luca, Di Trapani Vittorio, Delogu Pasquale, Donato Sandro, Dreossi Diego, Rigon Luigi, Longo Renata
National Institute for Nuclear Physics (INFN) - Trieste Division, Italy.
Department of Physical Sciences, Earth and Environment, University of Siena, Italy.
J Synchrotron Radiat. 2019 Mar 1;26(Pt 2):510-516. doi: 10.1107/S1600577519000237. Epub 2019 Feb 11.
In the case of single-distance propagation-based phase-contrast X-ray computed tomography with synchrotron radiation, the conventional reconstruction pipeline includes an independent 2D phase retrieval filtering of each acquired projection prior to the actual reconstruction. In order to compensate for the limited height of the X-ray beam or the small sensitive area of most modern X-ray photon-counting detectors, it is quite common to image large objects with a multi-stage approach, i.e. several acquisitions at different vertical positions of the sample. In this context, the conventional reconstruction pipeline may introduce artifacts at the margins of each vertical stage. This article presents a modified computational protocol where a post-reconstruction 3D volume phase retrieval is applied. By comparing the conventional 2D and the proposed 3D reconstructions of a large mastectomy specimen (9 cm in diameter and 3 cm in height), it is here shown that the 3D approach compensates for the multi-stage artifacts, it avoids refined projection stitching, and the image quality in terms of spatial resolution, contrast and contrast-to-noise ratio is preserved.
在基于单距离传播的同步辐射相衬X射线计算机断层扫描中，传统的重建流程包括在实际重建之前对每个采集的投影进行独立的二维相位恢复滤波。为了补偿X射线束的有限高度或大多数现代X射线光子计数探测器的小敏感区域，采用多阶段方法对大物体进行成像很常见，即在样品的不同垂直位置进行多次采集。在这种情况下，传统的重建流程可能会在每个垂直阶段的边缘引入伪影。本文提出了一种改进的计算协议，其中应用了重建后的三维体积相位恢复。通过比较一个大的乳房切除标本（直径9厘米，高3厘米）的传统二维和所提出的三维重建结果，表明三维方法补偿了多阶段伪影，避免了精细的投影拼接，并且在空间分辨率、对比度和对比度噪声比方面的图像质量得以保留。
