Physik-Department, Technische Universität München, 85748 Garching, Germany.
Phys Med Biol. 2010 Sep 21;55(18):5529-39. doi: 10.1088/0031-9155/55/18/017. Epub 2010 Aug 31.
The basic principles of x-ray image formation in radiology have remained essentially unchanged since Röntgen first discovered x-rays over a hundred years ago. The conventional approach relies on x-ray attenuation as the sole source of contrast and draws exclusively on ray or geometrical optics to describe and interpret image formation. Phase-contrast or coherent scatter imaging techniques, which can be understood using wave optics rather than ray optics, offer ways to augment or complement the conventional approach by incorporating the wave-optical interaction of x-rays with the specimen. With a recently developed approach based on x-ray optical gratings, advanced phase-contrast and dark-field scatter imaging modalities are now in reach for routine medical imaging and non-destructive testing applications. To quantitatively assess the new potential of particularly the grating-based dark-field imaging modality, we here introduce a mathematical formalism together with a material-dependent parameter, the so-called linear diffusion coefficient and show that this description can yield quantitative dark-field computed tomography (QDFCT) images of experimental test phantoms.
自一百多年前伦琴首次发现 X 射线以来，放射学中 X 射线成像的基本原理基本保持不变。传统方法仅依赖 X 射线衰减作为唯一的对比度来源，并完全依靠射线或几何光学来描述和解释成像形成。相衬或相干散射成像是可以使用波动光学而不是射线光学来理解的技术，它提供了通过将 X 射线与标本的波动光学相互作用结合起来来增强或补充传统方法的方法。利用最近基于 X 射线光学光栅的方法，先进的相衬和暗场散射成像方式现在可用于常规医学成像和无损检测应用。为了定量评估特别是基于光栅的暗场成像方式的新潜力，我们在这里引入了一个数学形式和一个与材料相关的参数，即所谓的线性扩散系数，并表明这种描述可以产生实验测试体模的定量暗场计算机断层扫描（QDFCT）图像。
