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的人 每年世界各地的男性和女性的数量。当前的新闻报道描述了新冠肺炎对呼吸的影响； 同样，在过去的一年里，人们广泛报道了蒸发引起的呼吸问题。世界范围内， 所有类型的肺病每年导致数百万人死亡，每年造成数万亿美元的惊人损失。 X线片和CT是肺部疾病的主要诊断影像工具。X线摄影和CT检查 擅长显示密度较高的结构，如肿瘤，但X射线吸收较低，局部密度变化较小 许多肺部疾病的特点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了 诊断性解释。低成本、安全、非侵入性诊断成像技术的开发 提供更好的肺组织可视化和肺部疾病是非常理想的。 X射线干涉成像潜在地满足了对肺部疾病更好的诊断成像的需求 种类繁多。X线片和CT对肺泡组织的丢失和小范围的结构相对不敏感 肺部的变化。相比之下，x射线干涉测量对这些部位的组织结构变化高度敏感。 长度刻度，由于X射线的绕射和散射的物理原理。干涉测量法同时提供了 一种具有两种类型的干涉图像的常规吸收图像：暗场和相位对比度。这个 “暗视野”图像特别适合于显示肺结构的微小变化。 精炼成像有限责任公司，与路易斯安那州立大学(LSU)和Pennington Biomedical合作 研究中心(PBRC)将建造一个用于肺部投影射线照相的X射线干涉测量系统，以及 进行一项小型试点研究，以说明其诊断能力。我们的目标是演示可视化 其性能可与CT媲美，但具有平面放射成像的低剂量和方便性。我们的 干涉仪在单次屏气中获取站立人肺部的扫描图像。按键设计 目标包括扫描时间为5秒，有效剂量小于35微西弗。这项初步研究将获得 路易斯安那州立大学肺科医生招募的15名COPD患者和5名健康志愿者的干涉图像。 干涉图像的解释以肺功能测试、X线片和CT为基准。 精炼成像有限责任公司和路易斯安那州立大学拥有构建概念验证的技术专长和经验 干涉成像系统。我们在PBRC的同事在临床研究方面拥有丰富的经验，而 路易斯安那州立大学的放射科医生和肺科医生提供肺部疾病的诊断、成像和管理方面的专业知识。 最终，精炼成像有限责任公司将与一家医疗成像系统制造商合作将其商业化 临床X射线干涉测量技术，将以较少的辐射剂量提供快速高质量的肺部成像 而且成本低于目前肺部CT所提供的成本。

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.