Grating-based X-ray Phase-contrast Tomography Methods

基于光栅的 X 射线相衬断层扫描方法

• 批准号: 8696391
• 负责人: Ge Wang
• 金额: $ 32.42万
• 依托单位: RENSSELAER POLYTECHNIC INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8696391
• 关键词: Algorithms; Animal Model; Animals; Area; Biological; Caliber; Communities; Computer software; Data; Diagnostic; Dose; Elements; Environment; Face; Fracture; Fracture Healing; Goals; Goat; Healed; High Performance Computing; Hospitals; Image; Light; Measures; Mechanics; Methods; Modeling; Pattern; Performance; Phase; Photons; Process; Property; Radiation; Refractive Indices; Relative (related person); Resolution; Resources; Roentgen Rays; Scanning; Signal Transduction; Software Engineering; Source; Structure; System; Techniques; Technology; Testing; Thinking; Tibial Fractures; Time; Tube; Validation; Variant; Weight-Bearing state; attenuation; base; bone; data acquisition; density; detector; flexibility; frontier; healing; image reconstruction; in vivo; innovation; interest; musculoskeletal imaging; novel; prototype; public health relevance; reconstruction; repaired; research study; response; simulation; soft tissue; synchrotron radiation; theories; tibia; tomography; transmission process

DESCRIPTION (provided by applicant): Biological soft tissue consists mainly of light elements, and its composition is nearly uniform with little density variation. Traditional attenuation-based x-ray imaging cannot provide sufficient contrast for this type of materials. The cross-section of x-ray phase shift is three orders of magnitude greater than that of x-ray attenuation in soft tissue over the diagnostic energy range. Hence, x-ray phase-contrast imaging is sensitive to subtle features especially micro-structures of soft tissue and offers superior contrast for analyses of various normal and diseased conditions. X-ray phase-contrast imaging approaches face challenges in biomedical applications. Analyzer-based phase- contrast imaging requires monochromatic x-rays and high-precision crystals, being limited to the synchrotron radiation facility. Propagation-based imaging suffers from a low photon flux of a micro-focus x-ray tube. Grating-based phase-contrast imaging is a recent breakthrough. However, two main obstacles for this paradigm shift are (1) the large-area gratings of small periods and high aspects and (2) the long time needed for data acquisition. Technically, it is rather difficult to make large gratings especially when x-ray energy is high. Theoretically, it is extremely complicated to model the propagation of x-rays through large gratings from a point x-ray source. In this project, we will establish two enabling innovations that are (1) interior phase contrast tomography for accurate region of interest (ROI) reconstruction and (2) few-view phase-contrast reconstruction without phase-stepping for accelerated data acquisition and minimized radiation dose. The synergistic combination of these innovations will define a new frontier of x-ray phase-contrast tomography. Although the conventional wisdom is that grating-based phase-contrast tomography must use sufficiently large gratings to cover an object and capture projections completely, our main innovative thinking is to target theoretically exact reconstruction over an ROI from truncated data collected with relatively small gratings. It is underlined that the grating-based phase-contrast interior reconstruction takes truncated differential projections, while the typical interior reconstruction assumes truncated direct projections. Another new idea for this project is to utilize the reweighted L1 norm for fewer-view image reconstruction. The overall goal of this project is to establish x-ray-grating-based interior tomography theory, develop the associated few-view reconstruction methods and system without phase stepping, and promote its biomedical applications. The proposed technology will be characterized in numerical simulation and phantom experiments, and applied for musculoskeletal imaging in an animal model. Upon the completion of this project, the proposed grating-based system will have achieved 30¿m resolution, shortened scanning time, and reduced radiation dose over a 3cm- diameter ROI, outperforming micro-CT in terms of contrast resolution yet delivering comparable ROI image quality relative to that of conventional grating-based phase-contrast tomography.

描述（由申请人证明）：生物软组织主要由传统的基于注意力的X射线成像组成。在诊断能量范围内，X射线的注意力是诊断能量范围的，尤其是软组织的微型结构，并为各种正常状况提供了卓越的对比度。对比度射线和高端限制，限制为脚趾同步设备的基于繁殖的成像受到微焦点X射线管的低光子通量。少量的光栅和（2）数据获取所需的长时间。我们将建立两个启用创新，分别是（1）内部阶段 对比度的对比度（ROI）（ROI）和（2）几乎没有相互对比的重建，而没有相位的相位，而没有相位的相位剂量，则可以定义X射线相 - 相 - 相位 - 辐射剂量。对比度是传统的智慧，是基于光栅的相位对比度层析成像必须使用大量覆盖物体并捕获投影，我们的主要创新思维是对收集的ROIC进行的目标精确重建基于光栅的阶段内部重建采用截断的扩散投影，典型的内部重建截断了直接的投影或更少的视图。 层状无需相位，并促进其生物医学应用。 M分辨率，缩短扫描时间以及在3厘米直径的ROI上减少辐射剂量，相对于基于基于Mackinting的阶段相位的相平进的档案分阶段置换型单层置换术的ROI图像图像质量可比。