298 results about "Phase-contrast imaging" patented technology

The application relates to a system and a method for the phase-contrast imaging by use of X-ray gratings. The system comprises an X-ray device, a first absorption grating, a second absorption grating, a detection unit, a data processing unit and an imaging unit, wherein the X-ray device transmits an X-ray bundle to a detected object; the first and second absorption gratings are positioned in the direction of the X-ray bundle; the X-ray refracted by the detected object forms an X-ray signal with variable intensity through the first absorption grating and/or the second absorption grating; the detection unit receives and converts the X-ray with variable intensity into an electrical signal; the data processing unit processes and extracts refraction-angle information in the electrical signal, and utilizes the refraction-angle information to figure out pixel information; and the imaging unit constructs images of the object. In addition, the system and the method can also realize CT imaging by using a rotating structure to rotate the object so as to obtain refraction angles in a plurality of projection directions and the corresponding images, and use CT reconstruction algorithm to figureout refraction-index fault images of the detected object. According to the invention, the phase-contrast imaging of approximate decimeter-magnitude viewing fields under incoherent conditions can be realized by use of common X-ray machines or multi-seam collimator such as source gratings, as well as two absorption gratings.

An interferometer for X-rays, in particular hard X-rays, for obtaining quantitative phase contrast images, includes a standard polychromatic X-ray source, a diffractive optical beam splitter other than a Bragg crystal in transmission geometry, and a position-sensitive detector with spatially modulated detection sensitivity.

A radiation phase contrast imaging apparatus, including a radiation emission unit having a plurality of electron sources for emitting electron beams, and a target for emitting radiation through collision of electron beam emitted from each electron source, a first grating in which grating structures for diffracting radiation are disposed periodically, a second grating in which grating structures for transmitting and shielding radiation are disposed periodically, and a radiation image detector for detecting radiation transmitted through the second grating, in which the first and second gratings are disposed in an optical axis direction of the radiation so as to be able to substantially superimpose each image of the first grating formed based on radiation corresponding to each electron source on a surface of the second grating, and the radiation corresponding to each electron source forms each phase image of the same subject on the radiation image detector.

The present invention relates to a method and a system for synthesizing an intensity pattern based on generalized phase contrast imaging. The phase filter contains a plurality of phase shifting regions that is matched to the layout of a light source array, each of the regions being positioned at the zero-order diffraction region of a respective element of the array. Further, the shape of each phase shifting region may match the shape of the zero-order diffraction region of the respective element. Thus, the energy of the electromagnetic fields of the system may be distributed over a large area compared to the area of a zero-order diffraction region of a single plane electromagnetic field of a known phase contrast imaging system.

The present invention generally refers to a correction method for grating-based X-ray differential phase contrast imaging (DPCI) as well as to an apparatus which can advantageously be applied in X-ray radiography and tomography for hard X-ray DPCI of a sample object or an anatomical region of interest to be scanned. More precisely, the proposed invention provides a suitable approach that helps to enhance the image quality of an acquired X-ray image which is affected by phase wrapping, e.g. in the resulting Moiré interference pattern of an emitted X-ray beam in the detector plane of a Talbot-Lau type interferometer after diffracting said X-ray beam at a phase-shifting beam splitter grating. This problem, which is further aggravated by noise in the obtained DPCI images, occurs if the phase between two adjacent pixels in the detected X-ray image varies by more than π radians and is effected by a line integration over the object's local phase gradient, which induces a phase offset error of π radians that leads to prominent line artifacts parallel to the direction of said line integration.

A 2D or 3D velocity field is reconstructed from a cross-correlation analysis of image pairs of a sample, without first reconstructing images of the sample spatial structure. The method can be implemented via computer tomographic x-ray particle image velocimetry, using multiple projection angles, with phase contrast images forming dynamic speckle patterns. Estimated cross-correlations may be generated via convolution of a measured autocorrelation function with a velocity probability density function, and the velocity coefficients iteratively optimised to minimise the error between the estimated cross-correlations and the measured cross-correlations. The method may be applied to measure blood flow, and the motion of tissue and organs such as heart and lungs.

The invention discloses a multi-mode micro-imaging system and method based on an LED array. The LED array serves as a microscope system light source and generates controllable multi-angle illumination light and a controllable illumination pore diameter, and bright field imaging, dark field imaging and difference phase contrast imaging are achieved. The realizable multi-mode imaging includes the three imaging modes of bright field imaging, dark field imaging and difference phase contrast imaging, and while bright field imaging, dark field imaging and difference phase contrast imaging are achieved, it is unnecessary to add any additional optical elements into the imaging path of a traditional microscope; in this way, an optical system is greatly simplified, and the LED array enables the microscope to have the capacity of flexibly adjusting the illumination pore diameter, the illumination angle and light source coherence.

Providing a radiation emission unit that includes a radiation source and outputs a fan beam of radiation, a diffraction grating onto which radiation outputted from the radiation emission unit is emitted, and a periodic information imaging radiation image detector that includes multiple linear electrodes and detects periodic information of radiation diffracted by the diffraction grating, disposing the radiation emission unit and the periodic information imaging radiation image detector such that an extending direction of the linear electrodes of the periodic information imaging radiation image detector is perpendicular to a fan surface of the fan beam having a larger spread angle, and configuring the radiation emission unit to scan the fan beam in the perpendicular direction.

This invention pertains to a method of low-cost intraoperative all field simultaneous parallel microbeam single fraction few seconds duration 100 to 1,000 Gy and higher dose radiosurgery with micro-electro-mechanical systems (MEMS)-carbon nanotube based microaccelerators. It ablates cancer cells including the mesenchymal epithelial transformation associated cancer stem cells. Microbeam brachy-therapeutic radiosurgery is performed. Microaccelerators are configured for simultaneous parallel microbeam emission from varying angels to an isocentric tumor. Their additive dose rate at the isocentric tumor is in the range of 10,000 to 20,000 Gy/s. It eliminates most tumor recurrence and metastasis which enhances cancer cure rates. It also exposes cancer antigens which induces cancer immunity. Stereotactic breast core biopsy is combined with, positron emission tomography and computerized tomography and phase-contrast imaging. Parallel microbeam brachytherapy preserves normal breast appearance. Migration of normal stem cells from unirradiated valley regions heals the radiation damage to the normal tissue.

A phase contrast image is generated on the basis of a plurality of radiation images of an object taken in imaging positions which are different from each other in the distance from the object. An enlargement/reduction processing is carried out on the radiation images as taken in the imaging positions according to the distances between the imaging positions so that the radiation images become substantially the same in their sizes, and a phase contrast image is generated on the basis of the radiation images thus processed.

Embodiments of methods and apparatus are disclosed for obtaining a phase-contrast digital imaging system and methods for same that can include an x-ray source for radiographic imaging; a beam shaping assembly, an x-ray grating interferometer including a phase grating and an analyzer grating; and an x-ray detector; where the source grating, the phase grating, and the analyzer grating are detuned and a plurality of uncorrelated reference images are obtained for use in imaging processing with the detuned system.

The present invention relates to phase-contrast imaging which visualizes the phase information of coherent radiation passing a scanned object. Focused gratings are used which reduce the creation of trapezoid profile in a projection with a particular angle to the optical axis. A laser supported method is used in combination with a dedicating etching process for creating such focused grating structures.

For correcting differential phase image data 52, differential phase image data 52 acquired with radiation at different energy levels is received, wherein the differential phase image data 52 comprises pixels 60, each pixel 60 having a phase gradient value 62a, 62b, 62c for each energy level. After that an energy dependent behavior of phase gradient values 62a, 62b, 62c of a pixel 60 is determined and a corrected phase gradient value 68 for the pixel 60 is determined from the phase gradient values 62a, 62b, 62c of the pixel 60 and a model for the energy dependence of the phase gradient values 62a, 62b, 62c.

X-ray devices for Phase Contrast Imaging (PCI) are often built up with the help of gratings. For large field-of-views (FOV), production cost and complexity of these gratings could increase significantly as they need to have a focused geometry. Instead of a pure PCI with a large FOV, this invention suggests to combine a traditional absorption X-ray-imaging system with large-FOV with an insertable low-cost PCI system with small-FOV, The invention supports the user to direct the PCI system with reduced FOV to a region that he regards as most interesting for performing a PCI scan thus eliminating X-ray dose exposure for scanning regions not interesting for a radiologist. The PCI scan may be generated on the basis of local tomography.

The invention discloses a super-resolution differential interference phase contrast microscopic imaging system. The system comprises a microscope, a light source, a first lens, a first reflecting mirror, a spatial light modulator, a third lens, a light barrier, a fourth lens and a charge coupled device (CCD), and the microscope is provided with a differential interference phase contrast imaging module. Simultaneously, the invention further discloses a microscopic imaging method based on the imaging system. According to the imaging system and the imaging method, extra sample preparation processes are not required, photobleaching effects and phototoxicity effects are absent, and the imaging contrast ratio is high.

The present invention relates to X-ray image acquisition technology in general. Employing phase-contrast imaging for X-ray image acquisition may significantly enhance the quality and information content of images acquired. However, phase-contrast information may only be obtainable in a small detector region, possibly being too small for a sufficient field of rotation view for specialized X-ray imaging applications. Accordingly, an apparatus for phase-contrast imaging is provided that may allow the acquisition of an enlarged field of view. According to the present invention an apparatus (1) for phase-contrast imaging is provided, comprising an X-ray source (2), an X-ray detector (12) element having a detector size, a beam splitter grating (8) and an analyzer grating (10). An object (6) is arrangeable between the X-ray source (2) and the X-ray detector (12). The beam splitter grating (8) and the analyzer grating (10) are arrangeable between the X-ray source (2) and the X-ray detector (12). X-ray source (2), the beam splitter grating (8), the analyzer grating (10) and the X-ray detector (12) are operatively coupled such that a phase-contrast image of the object (6) is obtainable. The apparatus (1) is adapted for acquiring a phase-contrast image having a field of view larger than the detector size. The X-ray detector element (12) is displaceable and by the displacement of the X-ray detector (12) a phase-contrast image of the field of view is obtainable.

An electron microscope according to the present invention includes a phase plate (510) having a thickness which changes in a radial direction, and adjusts a phase difference caused by a difference in electron beam path due to an effect of a spherical aberration when an electron beam is converged by a lens or an image of the electron beam is formed. Accordingly, the phase difference caused by the difference in electron beam path is adjusted, to thereby improve the coherence, so that a phase contrast image of transmitted electrons can be obtained at a higher resolution.