Publications by authors named "Ronald Ruth"
Article Synopsis
- There is a performance gap in monochromaticity and brilliance between conventional X-ray tubes and large-scale synchrotron sources, making synchrotrons impractical for smaller labs due to their size and cost.
- Laser-driven compact synchrotron light sources (CLS) offer a solution by combining an infrared laser with a small electron storage ring to produce high-quality monochromatic X-rays through inverse Compton scattering.
- A successful experiment demonstrated that CLS can achieve advanced X-ray multimodal tomography (including phase, dark-field, and attenuation-contrast) with impressive results, particularly in applications like CT scans of small animals, outperforming traditional methods.
Article Synopsis
- The study aimed to evaluate the effectiveness of grating-based X-ray dark-field imaging in diagnosing pulmonary emphysema and assessing its distribution more accurately compared to conventional X-ray projection images.
- The researchers used ex vivo imaging of lungs from mice with and without emphysema, comparing different signal parameters to determine their diagnostic value through ROC curve analysis.
- Results showed that the normalized scatter signal was the most effective in distinguishing between healthy and emphysematous tissue, providing detailed parametric maps that correlated well with histopathological findings.
Article Synopsis
- The study compares the contrast-to-noise ratio (CNR) of dark-field versus transmission signals in X-ray imaging of murine lung tissue ex vivo with the aim of assessing image quality.
- Lungs from three healthy mice were imaged, measuring background noise and image contrast in specific areas to calculate the relative contrast gain (RCG) of dark-field over transmission.
- Results showed that dark-field imaging had a higher CNR, especially in peripheral lung areas, which indicates it may provide better image quality compared to transmission imaging for this tissue type.
Iterative reconstruction has a wide spectrum of proven advantages in the field of conventional X-ray absorption-based computed tomography (CT). In this paper, we report on an algebraic iterative reconstruction technique for grating-based differential phase-contrast CT (DPC-CT). Due to the differential nature of DPC-CT projections, a differential operator and a smoothing operator are added to the iterative reconstruction, compared to the one commonly used for absorption-based CT data.
View Article and Find Full Text PDFArticle Synopsis
- Early detection of pulmonary diseases like emphysema and fibrosis is challenging with traditional X-ray techniques, which struggle to reveal changes in lung tissue.
- A new method using dark-field imaging, which captures small-angle scattering of X-rays, offers better differentiation between healthy and emphysematous lung tissues.
- The research employs a compact synchrotron X-ray source and shows that dark-field images significantly enhance diagnosis by correlating the dark-field signal with the size of alveoli in lung tissues.
Article Synopsis
- - The Compact Light Source is a small synchrotron that generates X-rays by using a technique called inverse Compton scattering, combining a laser pulse with an electron bunch.
- - It produces a highly coherent X-ray beam that has impressive monochromaticity and can be used for advanced imaging techniques, particularly high-sensitivity differential phase-contrast imaging.
- - Recent experiments using this technology at a clinically relevant X-ray energy of 21 keV showed enhanced contrast in imaging tests compared to traditional methods, highlighting its potential for better medical diagnostics.
Article Synopsis
- Structural genomics projects need X-ray diffraction and NMR spectroscopy for solving protein structures, and advanced facilities are often required for data collection.
- The paper introduces a new laboratory-scale synchrotron light source called the Compact Light Source, which can replicate many key synchrotron applications in X-ray science.
- Successful tests showcased its capability by determining the high-resolution structure of a protein from Mycobacterium tuberculosis using X-ray diffraction data from this new source.
The first imaging results obtained from a small-size synchrotron are reported. The newly developed Compact Light Source produces inverse Compton X-rays at the intersection point of the counter propagating laser and electron beam. The small size of the intersection point gives a highly coherent cone beam with a few milliradian angular divergence and a few percent energy spread.
View Article and Find Full Text PDFFully coherent x-ray pulses from a regenerative-amplifier free-electron laser.
Phys Rev Lett
April 2006
We propose and analyze a regenerative-amplifier free-electron laser (FEL) to produce fully coherent, hard x-ray pulses. The method makes use of narrow-bandwidth Bragg crystals to form an x-ray feedback loop around a relatively short undulator. Self-amplified spontaneous emission (SASE) from the leading electron bunch in a bunch train is spectrally filtered by the Bragg reflectors and is brought back to the beginning of the undulator to interact repeatedly with subsequent bunches in the bunch train.
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