Exploration of different x-ray Talbot–Lau setups for dark-field lung imaging examined in a porcine lung

Abstract

X-ray dark-field imaging is a promising technique for lung diagnosis. Due to the alveolar structure of lung tissue, a higher contrast is obtained by the dark-field image compared to the attenuation image. Animal studies indicate an enhancement regarding the detection of lung diseases in early stages. In this publication, we focus on the influence of different Talbot-Lau interferometer specifications while maintaining the x-ray source, sample magnification and detector system. By imaging the same porcine lung with three different grating sets, we analyze the contrast-to-noise ratio of the obtained dark-field images with respect to visibility and correlation length. We demonstrate that relatively large grating periods of the phase and of the analyzer grating are sufficient for high quality lung imaging at reasonable dose levels.

Technical Design Considerations of a Human-Scale Talbot-Lau Interferometer for Dark-Field CT

“…Based on this evaluation, the design parameters as stated in Table I have been derived and the resulting design yields a correlation length of 0.22 µm. While this cannot reach the challenging correlation length criterion demanded by [16] (this would require a 1.0 µm fine G 0 which is currently not feasible to fabricate), this leaves the proposed dark-field CT design at around half the sensitivity of the dark-field chest radiography system [20] which is operating successfully in clinical routine. We are confident that the tomographic reconstruction allows us to compensate for this drawback, as the volume reconstruction allows us to work with advanced processing and filtering approaches not applicable in radiographic imaging.…”

“…Another important design measure in dark-field setups is the correlation length ξ, which can be calculated from the sensitivity [16], [32]- [34]:…”

“…This now includes the wavelength λ as a dependency of the small-angle scattering sensitivity and goes beyond the spectral performance of the interferometer components themselves (i.e., performance of X-ray absorption gratings). A recent study suggests a correlation length of around 1 µm for lung imaging, which has been derived from several measurements with pig lungs at a specialized radiography setup [16]. Such a long correlation length requires a highly sensitive setup and is challenging to achieve, particularly in clinical designs.…”

Factors Affecting the Spatial Resolution in 2D Grating–Based X-Ray Phase Contrast Imaging

“…The microfocal X-ray source [7] or even a traditional X-ray tube can be used as the source [8,9]. This extends the application of X-ray phase contrast imaging technology [10][11][12][13]. In this technique, the spatial harmonic method is a variant grating-based method where absorption, differential phase contrast, and dark-field can be obtained from a single raw image [14][15][16].…”

Review and experimental verification of X-ray darkfield signal interpretations with respect to quantitative isotropic and anisotropic darkfield computed tomography

“…With the introduction of Talbot-Lau imaging to the laboratory by Pfeiffer et al [50,49], many more examples have been shown. Applications of X-ray darkfield imaging besides the characterization of micro-calcifications in mammography [38,15] include imaging of lungs [71,61,17,32], characterization of bone and dentin [51,43,27,26,21] as well as the analysis of general porous and fibrous materials or microscopic defects in the field of non destructive testing [54,24,16]. Other applications that have been shown include water transport in cement [52,70] or the monitoring of germinating seeds [44].…”