X-ray Dark-Field Imaging Techniques

1. 对研究背景的简要描述，包括潜在影响的x射线成像，对于在制造和安全领域的一系列应用中检查材料的内部结构以及临床环境中的疾病诊断至关重要。传统的x射线成像主要在样品的密度上显示对比度，而对于缺乏密度不均匀性的材料，在测量x射线的折射和散射时可以获得更好的对比度。x射线暗场成像是一种可以显示几十微米尺度上特征长度的密度变化的散射强度的方法。测量x射线暗场信号需要专门的设置，例如伦敦大学学院采用的边缘照明系统。如果由于纤维结构而存在密度变化，则该系统的方向灵敏度允许绘制这种纤维的方向。目的和目标本项目将围绕提高边缘照明系统的x射线暗场成像能力展开。目标侧重于改进数据采集和分析，以加快扫描时间，并改进从这种扫描中获得的信息。目标是：-系统掩模的自动对准，减少最有效地操作系统所需的专业知识-“单发”暗场成像，暗场CT -重建暗场信号的三维体-定向暗场成像-具有绘制样品内各向异性纤维散射体方向的能力-暗场张量层析成像-重建各向异性散射体的完整三维体3。研究方法的新颖性先前的研究已经在边缘照明系统中进行了掩模对准，但是，没有实现自动化的方法。目前正在调查单发相衬图像；然而，这还没有研究暗场对比。暗场CT、定向暗场和暗场张量断层扫描都已经在不同的x射线设置上实现，但尚未在边缘照明系统上进行研究，这可能会克服以前方法中的一些限制。与EPSRC的战略和研究领域保持一致本项目与EPSRC的医疗技术和工程战略保持一致。新的x射线成像技术可以提高医学影像学的疾病诊断能力，或者提高制造技术和材料工程的材料生产质量。任何公司或合作者参与目前没有，但如果成功，这个项目可以带给尼康计量，谁目前正在开发边缘照明XPCi系统。

1. Brief description of the context of the research including potential impact X-ray imaging is critical in the inspection of the inner structure of materials across a range of applications in manufacturing and security, as well as the diagnosis of disease in clinical settings. Whereas conventional X-ray imaging shows contrast primarily on the density of the sample, for materials with a lack of density inhomogeneities, superior contrast can be obtained when measuring the refraction and scattering of the X-rays. X-ray dark-field imaging is an approach that can show the strength of scattering from density variations with characteristic lengths on the scale of tens of microns. Measuring the X-ray dark-field signal requires a specialised setup, such as the Edge Illumination system employed at UCL. If density variations exist due to a fibrous structure, the directional sensitivity of the system allows the orientation of such fibres to be mapped.2. Aims and ObjectivesThis project will centre around improving the capabilities of X-ray dark-field imaging on the Edge Illumination system. The objectives focus on improving the data acquisition and analysis for faster scan times and improving the information available from such scans.The objectives are:- Automatic alignment of system masks, decreasing expertise required to operate the system most efficiently - "Single-Shot" dark-field imaging, where dark-field contrast can be acquired with a single exposure provided strict mask alignment - Dark-field CT - reconstructing a 3D volume of the dark-field signal - Directional dark-field imaging - with the ability to map the orientation of anisotropic fibrous scatterers within a sample - Dark-field tensor tomography - reconstructing a full 3D volume of anisotropic scatterers3. Novelty of the Research Methodology Previous research has been carried out into mask alignment in an Edge Illumination system, however, no automatized method has been implemented. Single-shot phase-contrast images are currently under investigation; however, this has not been investigated for dark-field contrast. Dark-field CT, directional dark-field and dark-field tensor tomography have all been implemented on a different x-ray setup, but yet to be investigated on an Edge Illumination system which would potentially overcome some limitations in the previous approaches.4. Alignment to EPSRC's strategies and research areas This project aligns with the EPSRC Healthcare Technologies and Engineering strategies. New x-ray imaging techniques can improve the ability to diagnose disease in Medical Imaging, or the quality of material production in Manufacturing Technologies and Materials Engineering. 5. Any Companies or Collaborators InvolvedNone at present, however if successful this project could be brought to Nikon Metrology, who are currently developing an Edge Illumination XPCi system.