The conventional form of computed tomography using X-ray attenuation without any contrast agents is of limited use for the characterization of soft tissue in many fields of medical and biological studies. Grating-based phase-contrast computed tomography (gbPC-CT) is a promising alternative imaging method solving the low soft tissue contrast without the need of any contrast agent. While highly sensitive measurements are possible using conventional X-ray sources the spatial resolution does often not fulfill the requirements for specific imaging tasks, such as visualization of pathologies. The focus of this study is the increase in spatial resolution without loss of sensitivity. To overcome this limitation a super-resolution reconstruction based on sub-pixel shifts involving a deconvolution of the image data during each iteration is applied. In our study we achieve an effective pixel size of 28 μm with a conventional rotating anode tube and a photon-counting detector. We also demonstrate that the method can upgrade existing setups to measure tomographies with higher resolution. The results show the increase in resolution at high sensitivity and with the ability to make quantitative measurements. The combination of sparse sampling and statistical iterative reconstruction may be used to reduce the total measurement time. In conclusion, we present high-quality and high-resolution tomographic images of biological samples to demonstrate the experimental feasibility of super-resolution reconstruction.

中文翻译：

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基于高分辨率实验室光栅的X射线相衬CT。

在许多医学和生物学研究领域中，使用不带任何造影剂的X射线衰减的计算机断层扫描的传统形式在软组织的表征中用途有限。基于光栅的相衬计算机断层扫描（gbPC-CT）是一种有前途的替代成像方法，无需任何造影剂即可解决低软组织对比度。尽管使用常规X射线源可以进行高度敏感的测量，但空间分辨率通常无法满足特定成像任务（例如病理学可视化）的要求。这项研究的重点是在不降低灵敏度的情况下提高空间分辨率。为了克服该限制，应用了基于子像素移位的超分辨率重建，该子像素移位包括在每次迭代期间对图像数据进行去卷积。在我们的研究中，使用传统的旋转阳极管和光子计数检测器可实现28μm的有效像素尺寸。我们还证明了该方法可以升级现有设置，以更高的分辨率测量断层扫描。结果表明，在高灵敏度下分辨率有所提高，并且具有进行定量测量的能力。稀疏采样和统计迭代重建的组合可以用来减少总的测量时间。总之，我们提出了高质量和高分辨率的生物样本断层图像，以证明超分辨率重建的实验可行性。我们还证明了该方法可以升级现有设置，以更高的分辨率测量断层扫描。结果表明，在高灵敏度下分辨率有所提高，并且具有进行定量测量的能力。稀疏采样和统计迭代重建的组合可以用来减少总的测量时间。总之，我们提出了高质量和高分辨率的生物样本断层图像，以证明超分辨率重建的实验可行性。我们还证明了该方法可以升级现有设置，以更高的分辨率测量断层扫描。结果表明，在高灵敏度下分辨率有所提高，并且具有进行定量测量的能力。稀疏采样和统计迭代重建的组合可以用来减少总的测量时间。总之，我们提出了高质量和高分辨率的生物样本断层图像，以证明超分辨率重建的实验可行性。