Phase Unwrapping in Spectral X-Ray Differential Phase-Contrast Imaging With an Energy-Resolving Photon-Counting Pixel Detector
Phase Unwrapping in Spectral X-Ray Differential Phase-Contrast Imaging With an Energy-Resolving Photon-Counting Pixel Detector
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DOI：
10.1109/tmi.2014.2349852
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发表时间：
2015-03-01
影响因子：
10.6
通讯作者：
Pfeiffer, Franz
中科院分区：
文献类型：
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作者：
Epple, Franz M.;Ehn, Sebastian;Pfeiffer, Franz
基于光栅的差分相衬成像已被证明是可行的与传统的X射线源。多色光谱通常限制了干涉仪的性能，但可以通过能量敏感探测器获得益处。在目前的工作中，我们采用的能量歧视能力，以纠正相位包裹文物。我们建议使用的相移，这是在不同的能量箱测量，估计最佳相移的意义上的最大似然。我们证明，我们的方法是能够纠正相位包裹文物，提高对比度噪声比，并减少由于建模的能量依赖性的射束硬化。该方法进行评估的实验数据上测量的实验室Talbot-Lau干涉仪配备了传统的多色X射线源和能量敏感的光子计数像素检测器。我们的工作表明，光谱成像是将差分相位衬度成像更接近临床前和临床应用的重要一步，其中相位包裹特别成问题。
Grating-based differential phase-contrast imaging has proven to be feasible with conventional X-ray sources. The polychromatic spectrum generally limits the performance of the interferometer but benefit can be gained with an energy-sensitive detector. In the presented work, we employ the energy-discrimination capability to correct for phase-wrapping artefacts. We propose to use the phase shifts, which are measured in distinct energy bins, to estimate the optimal phase shift in the sense of maximum likelihood. We demonstrate that our method is able to correct for phase-wrapping artefacts, to improve the contrast-to-noise ratio and to reduce beam hardening due to the modelled energy dependency. The method is evaluated on experimental data which are measured with a laboratory Talbot-Lau interferometer equipped with a conventional polychromatic X-ray source and an energy-sensitive photon-counting pixel detector. Our work shows, that spectral imaging is an important step to move differential phase-contrast imaging closer to pre-clinical and clinical applications, where phase wrapping is particularly problematic.