Implementation and validation of a lung x-ray interferometry imaging system, with applications to COPD, COVID-19 and other lung diseases

摘要 从癌症到慢性阻塞性肺疾病（COPD）的肺部疾病影响着大量 每年全世界的男人和女人。目前的新闻报道描述了COVID-19对呼吸系统的影响; 同样，过去一年也广泛报道了电子烟引起的呼吸系统问题。在全球范围内， 所有类型的肺部疾病每年导致数百万人死亡，每年花费惊人的数万亿美元。 X线摄影和CT是肺部疾病的主要影像诊断工具。X线摄影和CT检查 很好地显示了更致密的结构，如肿瘤，但X射线吸收低，密度的局部变化小 限制了肺组织本身的可视化。虽然技术如 放射组学可以从图像中提取额外的信息，次优的肺部图像质量固有地限制 诊断解释低成本、安全、非侵入性诊断成像技术的发展， 提供肺组织和肺部疾病的改进的可视化是非常期望的。 X射线干涉成像可能满足对肺部疾病更好的诊断成像的需求， 很多类型。X线摄影和CT对牙槽骨组织和小范围结构的丢失相对不敏感 肺部的变化。相比之下，X射线干涉测量法对这些组织结构变化高度敏感。 由于X射线的衍射和散射的物理学原理，干涉测量同时提供 具有两种类型的干涉图像的常规吸收图像：暗场和相位对比。的 “暗场”图像特别适合于使肺结构中的小变化可视化。 Refined Imaging LLC，与路易斯安那州立大学（LSU）和彭宁顿生物医学 研究中心（PBRC）将构建一个用于肺部投影X射线摄影的X射线干涉测量系统，并且 进行一项小型试点研究，以说明其诊断能力。我们的目标是展示可视化 与CT相比，它具有更好的功能，但具有平面X线摄影的低剂量和方便性。我们 干涉仪在单次屏气中获取站立的人的肺部的扫描图像。关键设计 目标包括5秒的扫描时间和小于35 µSv的有效剂量。试点研究将获得 LSU肺病学家招募的15名COPD患者和5名健康志愿者的干涉测量图像。 干涉测量图像的解释以肺功能测试、放射照相术和CT为基准。 Refined Imaging LLC和LSU拥有构建概念验证的技术专长和经验 干涉成像系统我们PBRC的同事在临床研究方面拥有丰富的经验，同时 路易斯安那州立大学放射科医生和肺病学家提供诊断、成像和肺部疾病管理方面的专业知识。 最终，Refined Imaging LLC将与一家医疗成像系统制造商合作， 临床X射线干涉测量技术，可提供快速高质量的肺部成像，辐射剂量更少 并且比目前肺部CT的成本更低。

Abstract Lung diseases ranging from cancer to chronic obstructive pulmonary disease (COPD) affect large numbers of men and women worldwide each year. Current news reports describe the respiratory impact of COVID-19; likewise, the past year has seen extensive coverage of the respiratory problems caused by vaping. Worldwide, lung diseases of all types result in millions of deaths per year at a staggering cost of trillions of dollars annually. Radiography and CT are the primary diagnostic imaging tools for lung diseases. Radiography and CT do well at visualizing denser structures such as tumors, but low x-ray absorption and small local changes in density that characterize many lung diseases limit the visualization of lung tissue itself. While techniques such as radiomics can extract additional information from images, suboptimal lung image quality inherently limits diagnostic interpretation. The development of a low-cost, safe, non-invasive diagnostic imaging technique that provides improved visualization of lung tissue and lung diseases is highly desirable. X-ray interferometry imaging potentially answers the need for better diagnostic imaging of lung diseases of many types. Radiography and CT are relatively insensitive to loss of alveolar tissue and small-scale structural changes in the lung. By comparison, x-ray interferometry is highly sensitive to tissue structural changes at these length scales, due to the physics of diffraction and scattering of x-rays. Interferometry simultaneously provides a conventional absorption image with two types of interferometric images: dark-field and phase contrast. The “dark-field” image is especially well-suited to visualizing small changes in lung structure. Refined Imaging LLC, in collaboration with Louisiana State University (LSU) and Pennington Biomedical Research Center (PBRC), will construct an x-ray interferometry system for projection radiography of lungs, and conduct a small pilot study to illustrate its diagnostic capabilities. Our goal is to demonstrate visualization capabilities that compare favorably to CT, but with the low dose and convenience of planar radiography. Our interferometer acquires a scanned image of the lungs of a standing person in a single breath hold. Key design targets include a scan time of 5 seconds and an effective dose less than 35 µSv. The pilot study will acquire interferometry images for 15 COPD patients and 5 healthy volunteers recruited by LSU pulmonologists. Interpretation of interferometry images is benchmarked against pulmonary function test, radiography and CT. Refined Imaging LLC and LSU have the technical expertise and experience to construct the proof-of-concept interferometry imaging system. Our colleagues at PBRC have substantial experience with clinical studies, while LSU radiologists and pulmonologists provide expertise in diagnosis imaging and management of lung disease. Ultimately, Refined Imaging LLC will partner with a medical imaging systems manufacturer to commercialize clinical X-ray interferometry technology, which will provide fast high-quality lung imaging with less radiation dose and lower cost than currently available from lung CT.