Department of Physics, University of Houston, Houston, TX 77204, USA.
Sensors (Basel). 2019 Nov 18;19(22):5022. doi: 10.3390/s19225022.
Energy-resolving photon-counting detectors (PCDs) separate photons from a polychromatic X-ray source into a number of separate energy bins. This spectral information from PCDs would allow advancements in X-ray imaging, such as improving image contrast, quantitative imaging, and material identification and characterization. However, aspects like detector spectral distortions and scattered photons from the object can impede these advantages if left unaccounted for. Scattered X-ray photons act as noise in an image and reduce image contrast, thereby significantly hindering PCD utility. In this paper, we explore and outline several important characteristics of spectral X-ray scatter with examples of soft-material imaging (such as cancer imaging in mammography or explosives detection in airport security). Our results showed critical spectral signatures of scattered photons that depend on a few adjustable experimental factors. Additionally, energy bins over a large portion of the spectrum exhibit lower scatter-to-primary ratio in comparison to what would be expected when using a conventional energy-integrating detector. These important findings allow flexible choice of scatter-correction methods and energy-bin utilization when using PCDs. Our findings also propel the development of efficient spectral X-ray scatter correction methods for a wide range of PCD-based applications.
能量分辨光子计数探测器（PCD）可将来自多色 X 射线源的光子分离到多个单独的能量bins 中。PCD 的这种光谱信息将允许 X 射线成像技术的进步，例如提高图像对比度、定量成像以及材料识别和特性分析。然而，如果不加以考虑，探测器光谱失真和物体散射光子等方面可能会阻碍这些优势的实现。散射 X 射线光子在图像中充当噪声，并降低图像对比度，从而严重阻碍 PCD 的实用性。在本文中，我们通过软物质成像（例如乳腺 X 光检查中的癌症成像或机场安检中的爆炸物检测）的示例，探讨并概述了光谱 X 射线散射的几个重要特性。我们的结果显示了散射光子的关键光谱特征，这些特征取决于几个可调节的实验因素。此外，与使用传统能量积分探测器相比，在光谱的大部分能量bins 中，散射与初级射线的比值较低。这些重要发现允许在使用 PCD 时灵活选择散射校正方法和能量bins 的利用。我们的研究结果还推动了针对各种基于 PCD 的应用的高效光谱 X 射线散射校正方法的发展。
