Trabecular bone anisotropy imaging with a compact laser-undulator synchrotron x-ray source

Abstract

Conventional x-ray radiography is a well-established standard in diagnostic imaging of human bones. It reveals typical bony anatomy with a strong surrounding cortical bone and trabecular structure of the inner part. However, due to limited spatial resolution, x-ray radiography cannot provide information on the microstructure of the trabecular bone. Thus, microfractures without dislocation are often missed in initial radiographs, resulting in a lack or delay of adequate therapy. Here we show that x-ray vector radiography (XVR) can overcome this limitation and allows for a deeper insight into the microstructure with a radiation exposure comparable to standard radiography. XVR senses x-ray ultrasmall-angle scattering in addition to the attenuation contrast and thereby reveals the mean scattering strength, its degree of anisotropy and the orientation of scattering structures. Corresponding to the structural characteristics of bones, there is a homogenous mean scattering signal of the trabecular bone but the degree of anisotropy is strongly affected by variations in the trabecular structure providing more detailed information on the bone microstructure. The measurements were performed at the Munich Compact Light Source, a novel type of x-ray source based on inverse Compton scattering. This laboratory-sized source produces highly brilliant quasi-monochromatic x-rays with a tunable energy.

Simultaneous wood and metal particle detection on dark-field radiography

“…Thüring et al [ 30 ] presented an overview on the presentation of the bony structure of the hand in dark-field imaging. Further information on the anatomical structure of the bones can be assessed with grating-based x-ray vector radiography [ 31 ].…”

A compact light source providing high-flux, quasi-monochromatic, tunable X-rays in the laboratory

“…Given the biomedical imaging research focus of the TUM group, a large number of application examples has been generated in this area. 8,[10][11][12][13][14][15][16][17][18][21][22][23][24][25][26][28][29][30][31] While earlier experiments focused on demonstrating different X-ray imaging techniques on the CLS, such as mono-energy X-ray absorption tomography, grating-based multimodal imaging, propagation-based phase contrast and phase contrast tomography, these are now applied to specific biomedical applications and extended to advanced techniques, such as dynamic imaging, K-edge subtraction imaging and others.…”

“…19,20 The MuCLS has been operating with a high degree of uptime since then and has enabled many scientific experiments and publications. [21][22][23][24][25][26][27][28][29][30][31] Generally, most X-ray techniques such as diffraction, imaging, spectroscopy or scattering can be performed with both electron-impact and synchrotron sources. While the details depend on the technique and the specific application needs, generally the following guidelines apply: Longer measurement times Shorter measurement times Lower resolution and sensitivity Higher resolution and sensitivity Suitable where fixed energy or polychromatic beam is acceptable Required where tunability and/or monochromaticity is required Advantageous for large sample sizes (e.g., imaging of large components and low or moderate resolution)…”

Full-field structured-illumination super-resolution X-ray transmission microscopy

“…Accordingly, for now we see our full-field structured-illumination super-resolution X-ray transmission microscopy approach as a complementary technique for larger specimens to the sub-50 nm STXM and TXM microscopes, which are limited to very small specimen sizes of the order of a few hundred micrometres. Combining our method with recently developed brilliant compact inverse Compton sources, whose coherence has been demonstrated to be sufficient for Talbot interferometry 27–29 , is straightforward. Implementation of a source grating, known from Talbot–Lau interferometry 12 , will make this technique feasible also at high power (rotating anode) X-ray tubes.…”