X-ray phase-contrast tomography with a compact laser-driven synchrotron source

Abstract

Between X-ray tubes and large-scale synchrotron sources, a large gap in performance exists with respect to the monochromaticity and brilliance of the X-ray beam. However, due to their size and cost, large-scale synchrotrons are not available for more routine applications in small and medium-sized academic or industrial laboratories. This gap could be closed by laser-driven compact synchrotron light sources (CLS), which use an infrared (IR) laser cavity in combination with a small electron storage ring. Hard X-rays are produced through the process of inverse Compton scattering upon the intersection of the electron bunch with the focused laser beam. The produced X-ray beam is intrinsically monochromatic and highly collimated. This makes a CLS well-suited for applications of more advanced--and more challenging--X-ray imaging approaches, such as X-ray multimodal tomography. Here we present, to our knowledge, the first results of a first successful demonstration experiment in which a monochromatic X-ray beam from a CLS was used for multimodal, i.e., phase-, dark-field, and attenuation-contrast, X-ray tomography. We show results from a fluid phantom with different liquids and a biomedical application example in the form of a multimodal CT scan of a small animal (mouse, ex vivo). The results highlight particularly that quantitative multimodal CT has become feasible with laser-driven CLS, and that the results outperform more conventional approaches.phase-contrast tomography | dark-field tomography | grating interferometer | inverse Compton X-rays | X-ray imaging W ith the introduction of the grating interferometer (1-3), the field of X-ray phase-contrast imaging has seen great advances in the past decade. In comparison with conventional attenuation-contrast imaging, the phase-contrast modality greatly improves soft-tissue contrast, which can, for example, be used for better tumor visualization (4). With the development of the TalbotLau interferometer, grating-based phase-contrast imaging has become feasible not only with synchrotron sources, but also with standard X-ray tube sources (3, 5). On the downside, the visibility is degraded due to the broad polychromatic spectrum of the X-ray tube sources, thus compromising the image quality. Brilliant and highly monochromatic synchrotron sources yield superior results for high-resolution and high-sensitivity measurements (2, 4, 6-13).However, limited availability, high cost, and small fields of view make synchrotron sources incompatible with clinical applications or preclinical research on, e.g., small-animal disease models in close vicinity to biomedical laboratories with small-animal infrastructure. Offering a monochromatic beam as well as higher brilliance and coherence than X-ray tube sources, compact synchrotron sources can be classified between tube sources and synchrotron sources. These features are achieved with a compact light source (CLS), which has a size that is compatible with conventional laboratories, making it an interesting candidate for preclinical and mater...

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