Energy dispersive X-ray transmission imaging and coherent scatter tomography

研究的主要目标和目的x射线成像是一项关键技术，用于许多领域，如医学诊断，质量控制和材料测试，允许调查否则不透明的体积。3D图像可以通过拍摄许多平面x射线图像并执行称为计算机断层扫描（CT）重建的过程来产生。该项目旨在开发一种3D成像技术，与普通的x射线成像不同，它可以根据散射x射线的方式来区分不同的材料。样品被一束狭窄的x射线照射，“离轴”测量记录了散射剖面。由于被称为x射线衍射（XRD）的现象，在散射剖面中观察到依赖于材料原子结构的特征。由于每种材料都有不同的结构，因此该轮廓可以用作识别未知材料的指纹。最终，通过应用相同的CT重建过程，该技术可以提供任何感兴趣体积的3D地图，以确定存在哪些材料及其位置。目前的XRD CT方法涉及到一个漫长的过程，即在样品平移和旋转时进行单独的点测量。该项目的新颖之处在于进一步发展该技术以减少扫描时间。这将通过实施多波束技术和稀疏数据收集策略的组合来实现。学生将使用最先进的x射线探测器（HEXITEC），这将实现最有效的数据收集，消除了缓慢的样本翻译步骤的需要。生成的数据将是复杂的，学生还将开发软件来组织，插值和重建三维空间分辨散射剖面。该技术具有提供3D空间分辨材料识别的能力。这在以下应用领域具有广泛的潜力：在癌症手术时对切除的组织进行分析，以确保所有病变组织已被切除。手术后发现切除的组织不足的患者复发的风险更大，可能需要进一步治疗（即卫生保健提供者的额外费用和患者焦虑的增加）。在安全检查中发现毒品、爆炸物和违禁品，而行李的布局和内容（例如）是未知的。制造过程中的缺陷识别。例如，在复合材料制造中，需要识别可能导致结构失效的空隙、夹杂物和富含树脂的区域。在肉类行业，为了食品安全，需要识别异物或损坏的产品。还有一种转变是使用技术对产品进行数字化分级，以提高产量（增加经济价值）并减少浪费（减少对环境的影响）。

Key Objectives and Aims of the ResearchX-ray imaging is a key technique used in many fields such as medical diagnostics, quality control and materials testing, permitting the investigation of otherwise opaque volumes. 3D images can be produced by taking many flat X-ray images and performing a process known as computed tomography (CT) reconstruction. This project aims to develop a 3D imaging technique that, unlike normal X-ray imaging, discriminates different materials based on how they scatter X-rays. A sample is illuminated by a narrow beam of X-ray and 'off-axis' measurements recorded the scattering profile. Features are observed in the scattering profile which depend on the atomic structure of material due to a phenomena known as X-ray diffraction (XRD). Since every material has a different structure, the profile can be used as a fingerprint to identify unknowns. Ultimately, by applying the same CT reconstruction process, this technique can provide a 3D map of any volume of interest to determine what materials are present and where they are located.Novel ScienceCurrent approaches to XRD CT involve a lengthy process of making individual point measurements as the sample is translated and rotated. The novel aspect of this project is to develop this technique further to reduce scan times. This will be through a combination of implementing multi beam techniques and sparse data collection strategies. The student will use a cutting edge X-ray detector (HEXITEC) which will enable the most efficient data collection, removing the need for the slow sample translation step. The data produced will be complicated and the student will also develop software to organise, interpolate and reconstruct the spatially resolved scattering profiles in 3D.Potential ApplicationsThe technique has the power to provide 3D spatially resolved material identification. This has wide ranging potential in the following application areas:Analysis of excised tissue at the time of cancer surgery to ensure that all diseased tissue has been removed. Patients who, post-surgery, are discovered to have had insufficient tissue removed are at greater risk of recurrence and may require further treatment (i.e. additional cost to the health care provider and increased patient anxiety).Drug, explosive and contraband detection in security screening where the layout and content of baggage (for example) is unknown.Defect identification in manufacturing processes. For example, in composites fabrication there is a need to identify voids, inclusions and resin rich areas which could lead to structural failure.In the meat industry there is a requirement to identify foreign objects or damaged products for food safety. There is also a shift towards using technology to digitally grade products in order to increase yield (increasing economic value) and reduce waste (reducing environmental impact).