نتایج جستجو برای: ray imaging
تعداد نتایج: 712871 فیلتر نتایج به سال:
Discovered by Wilhelm Roentgen in 1895, X-ray technology is the oldest and most commonly used form of medical imaging and remains an important tool for the diagnosis of many disorders. X-rays are generated when a beam of electrons is accelerated by high voltage and hits a metal probe. The kinetic energy released is transformed into quanta of emitted X-ray radiation. X-rays are absorbed by the m...
X-ray microtomography has been developed for use in various fields such as biology, materials science, petrology, and medical diagnosis. This method’s setup commonly consists of a simple projection geometry with a high-resolution imaging detector and a highly collimated beam, e .g . , a microfocussing X-ray tube or synchrotron radiation source, which can result in a spatial resolution of about ...
A significant improvement over conventional attenuation-based X-ray imaging, which lacks contrast in small objects and soft biological tissues, is obtained by introducing phase-contrast imaging. As recently demonstrated, phase-contrast imaging is characterized by its extraordinary image quality, greatly enhanced contrast, and good soft tissue discrimination with very high spatial resolution dow...
X-ray luminescence optical tomography (XLOT) is an emerging hybrid imaging modality in which x-ray excitable particles (phosphor particles) emit optical photons when stimulated with a collimated x-ray beam. XLOT can potentially combine the high sensitivity of optical imaging with the high spatial resolution of x-ray imaging. For reconstruction of XLOT data, we compared two reconstruction algori...
چکیده ندارد.
X-ray imaging in differential interference contrast (DIC) with submicrometer optical resolution was performed by using a twin zone plate (TZP) setup generating focal spots closely spaced within the TZP spatial resolution of 160 nm. Optical path differences introduced by the sample are recorded by a CCD camera in a standard full-field imaging and by an aperture photodiode in a standard scanning ...
We study the possibilities of direct (using one intersection with each light ray) stigmatic imaging with a curved surface that can change ray directions in an arbitrary way. By purely geometric arguments we show that the only possible case of such imaging is the trivial one where the image of any point is identical to the point itself and the surface does not perform any change of the ray direc...
Progress in lithography and nanofabrication @E. Di Fabrizio et al., Nature ~London! 401, 895 ~1999!# has made it possible to apply differential interference contrast ~DIC! in x-ray microscopy using an original x-ray doublet lens based on two specially developed zone plates. Switching from bright-field imaging ~absorption contrast! to x-ray DIC, we observe, similar to visible-light microscopy, a...
We report the recording and reconstruction of x-ray diffraction patterns from single, unstained viruses, for the first time. By separating the diffraction pattern of the virus particles from that of their surroundings, we performed quantitative and high-contrast imaging of a single virion. The structure of the viral capsid inside a virion was visualized. This work opens the door for quantitativ...
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