Abstract: Scattered X-rays scattered by an object or a structure enter in a detector (a shift detector) for detecting the positional shift of an X-ray focal point and become a noise source, thereby deteriorating the positional shift detection precision. In particular, the estimation of the dose of scattered X-rays originating from the object is difficult prior to the measurement, and correction of the scattered X-rays is important in order to precisely calculate the positional shift of the X-ray focal point. In order to address this drawback, according to the present invention, a scattered X-ray detector 6 is provided which measures the dose of scattered rays entering in a shift detector 5 for detecting the positional shift of an X-ray focal point 9, and has a function that the output by the shift detector 5 is corrected using the scattered ray dose measured by the scattered X-ray detector.

Abstract: A system and method for forming an adjusted estimate of scattered radiation in a radiographic projection of a target object, which incorporates scattered radiation from objects adjacent to the target object, such as a patient table. A piercing point equalization method is disclosed, and a refinement of analytical kernel methods which utilizes hybrid kernels is also disclosed.

Abstract: A system and method for forming an adjusted estimate of scattered radiation in a radiographic projection of a target object, which incorporates scattered radiation from objects adjacent to the target object, such as a patient table. A piercing point equalization method is disclosed, and a refinement of analytical kernel methods which utilizes hybrid kernels is also disclosed.

Abstract: In an X-ray computer tomograph and a method for investigating an object by means of X-ray computer tomography, to improve the image quality, a first intensity of the X-ray radiation between an X-ray source and the object is measured by means of a first intensity measurement device (13) and a second intensity of the X-ray radiation between the object and the X-ray detector outside a projection region of the object is measured by means of a second intensity measurement device. A scattered radiation correction factor is calculable by means of the measured intensities to reduce the scattered radiation.

Abstract: An imaging technique is provided for acquiring scatter free images of an object. The technique includes acquiring a plurality of projection images of the object using a source and a detector oriented at a plurality of projection angles relative to the object, and generating a plurality of scatter free projection images by correcting the plurality of projection images based on respective ones of a plurality of stored scatter images. The scatter images are generated and stored for each of the projection angles by positioning a scatter rejection plate between the object and the detector. The technique further includes reconstructing a three-dimensional image of the object based on the scatter free projection images.

Abstract: In order to improve the tiling workability in manufacturing an X-ray detector and provide a technology for acquiring high-quality reconstruction images, when aligning a plurality of detector blocks (or detector modules) in a slice direction, a distance between adjacent X-ray detection elements between detector blocks (inter-block distance) is not matched with a distance between adjacent detector elements within a detector block (intra-block distance). Instead, between reference positions when manufacturing each detector block, output values at the positions, the number of which is the same as the number of X-ray detection elements between the reference positions and which are spaced at equal intervals, are estimated from the acquired raw data. Projection data is generated from the position and the raw data.

Abstract: A general imaging scheme is proposed for applications of CBCT. The approach provides a superior CBCT image quality by effective scatter correction and noise reduction. Specifically, in its implementation of CBCT imaging for radiation therapy, the proposed approach achieves an accurate patient setup using a partially blocked CBCT with a significantly reduced radiation dose. The image quality improvement due to the proposed scatter correction and noise reduction also makes CBCT-based dose calculation a viable solution to adaptive treatment planning.

Abstract: An X-ray CT apparatus according to an embodiment includes an X-ray detector and a collimator unit. The X-ray detector detects X-rays that have passed through a subject. The collimator unit eliminates scattered radiation from X-rays that are incident on the X-ray detector. The collimator unit includes a plurality of collimator modules, a supporter, and a fixing unit. The plurality of collimator modules each includes a plurality of first collimator plates arranged in a grid along a channel direction and a slice direction that are orthogonal to each other. The supporter supports the collimator modules such that the collimator modules are aligned in a plurality of straight lines along the channel direction and in a plurality of straight lines along the slice direction. The fixing unit is provided to the supporter and fixes positions of the collimator modules in the channel direction and the slice direction.

Abstract: The present invention relates to the field of x-ray imaging. More particularly, embodiments of the invention relate to methods, systems, and apparatus for imaging, which can be used in a wide range of applications, including medical imaging, security screening, and industrial non-destructive testing to name a few.

Abstract: A detector having a collimator in a position at a specific angle with respect to a therapeutic X-ray beam is mounted to selectively detect only scattering radiation in the direction. To three-dimensionally obtain a distribution of places where scattering occurs in a patient body, a detector is rotated during irradiation and scattering radiation is measured from all of directions. After that, a reconstructing process is performed, and a distribution of occurrence of scattering radiation in the subject is three-dimensionally imaged. Since angles and amounts of X-rays scattered by Compton scattering are known theoretically, if scattering radiation at a certain angle can be detected, the number of scattering radiation at other angles can be also estimated. On the basis of the theory, images of distribution of scattering radiation sources are converted to images of distribution of absorption of radiation.

Abstract: A method and imaging system for operating imaging computed tomography using a radiation source and a plurality of detectors to generate an image of an object. The method includes: defining a desired image characteristics; and performing calculations to determine the pattern of fluence to be applied by the radiation source, to generate said desired image quality or characteristics. Then, the radiation source is modulated, to generate the intended pattern of fluence between the beam source and the object to be imaged. The desired image characteristics can comprise at least one of desired levels of contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR), and may provide at least one of: desired image quality in at least one defined region of interest; and at least one desired distribution of said image quality.

Abstract: A multi-emitter computed tomography scanner is disclosed, including a plurality of x-ray emitter/detector arrangement pairs arranged offset at an angle to one another. In at least one embodiment, the detector arrangements of the pairs are designed to be energy selective.

Abstract: A CT scanner with scatter correction device and a method for scatter correction are provided. The method of correcting CT images from artifacts caused by scattered radiation comprises affixing to the non-rotating frame of the CT gantry a plurality of shields for shielding some of the CT detector elements from direct X ray radiation, while allowing scattered radiation to arrive at said shielded elements; measuring scatter signals from said shielded elements, indicative of scattered radiation intensity; and correcting for scatter by subtracting scatter intensity values estimated from said measured scatter signals from signals measured by unshielded detector elements.

Abstract: A radiation imaging apparatus acquires information on a scattered radiation distribution at each rotation angle preliminarily determined for a rotation unit, based on images respectively obtained from a first radiation detection sensor having no grid, and a second radiation detection sensor having a grid. Then, the radiation imaging apparatus corrects the image obtained from the second radiation detection sensor based on the information on the scattered radiation distribution so as to reduce influence of scattered radiation thereon. Next, the radiation imaging apparatus performs reconstruction processing based on the image corrected by the correction unit.

Abstract: A system and method for forming an adjusted estimate of scattered radiation in a radiographic projection of a target object, which incorporates scattered radiation from objects adjacent to the target object, such as a patient table. A piercing point equalization method is disclosed, and a refinement of analytical kernel methods which utilizes hybrid kernels is also disclosed.

Abstract: A system and method for forming an adjusted estimate of scattered radiation in a radiographic projection of a target object, which incorporates scattered radiation from objects adjacent to the target object, such as a patient table. A piercing point equalization method is disclosed, and a refinement of analytical kernel methods which utilizes hybrid kernels is also disclosed.

Abstract: Disclosed is an X-ray imaging apparatus in which a correction function used to correct scattered X-rays and a correction function used to correct beam hardening can be simply and precisely determined so that the correcting operations are performed in an appropriate sequence using the correction functions thus determined to enhance the precision in the correction and improve the image quality. The scattered X-rays and the beam hardening are corrected sequentially in this order, using the scattered X-ray correction function and the beam hardening correction function, both calculated using measured data for calculating the correction functions. The scattered X-ray correction function approximates as to each transmission distance, the data measured with changes in the transmission distance and with changes in the scattered X-ray amount, and associates the correction value thus obtained with transmittance data.

Abstract: Disclosed are methods, systems, and computer-product programs for increasing accuracy in cone-beam computed tomography (CBCT) by obscuring portions of the radiation source so that the radiation only passes through the specific areas of the patient related to the regions-of-interest to the doctor. The obscuring action causes less radiation scattering to occur in the patient's body, thereby reducing a major source of error in the image accuracy caused by scattered radiation. Scattered radiation received by detector pixels that are obscured by direct-line of sight radiation may be used to estimate the scattered radiation in the un-obscured portion, which can be used to further increase the accuracy of the image.

Abstract: A method includes generating a plurality of scatter distributions based on geometric models having different object to detector distances, determining an imaged object to detector distance, and identifying a scatter distribution of the plurality of scatter distributions having a object to detector distance that corresponds to the imaged object to detector distance. The method also includes employing the identified scatter distribution to scatter correct projection data corresponding to the imaged object. Another method includes generating an estimate of wedge scatter by propagating a predetermined wedge scatter profile through an intermediate reconstruction of an object; and employing the estimate to wedge scatter correct the projection data.

Abstract: The present invention relates to an imaging apparatus for generating an image of a region of interest of an object. The imaging apparatus comprises a radiation source (2) for emitting radiation (4) and a detector (6) for measuring the radiation (4) after having traversed the region of interest and for generating measured detection values depending on the measured radiation (4). The imaging apparatus further comprises an attenuation element for attenuating the radiation (4) before traversing the region of interest and an attenuation element scatter values providing unit (12) for providing attenuation element scatter values, which depend on scattering of the radiation (4) caused by the attenuation element. A detection values correction unit (17) corrects the measured detection values based on the provided attenuation element scatter values, and a reconstruction unit (18) reconstructs an image of the region of interest from the corrected detection values.

Abstract: A method and system for acquiring, processing, storing, and displaying x-ray mammograms Mp tomosynthesis images Tr representative of breast slices, and x-ray tomosynthesis projection images Tp taken at different angles to a breast, where the Tr images are reconstructed from Tp images

Abstract: A method for scaling a scattered ray intensity distribution in a multi bulbs X-ray CT apparatus configured to irradiate a subject with X-rays from a plurality of X-ray generation sections, respectively and configure a cross-sectional image of the subject by detecting the X-rays passing through the subject. A first difference is achieved, the first difference being the difference between a real data of X-ray intensity achieved by passing of X-rays through the subject, the X-rays being radiated from the plurality of the X-ray generation sections, respectively and an opposed data of X-ray intensity achieved by passing of these X-rays through the subject at the same position in an opposite direction, a second difference between scattered ray intensity included in the real data and scattered ray intensity included in the opposed data being achieved.

Abstract: In one aspect, A method of imaging an object of interest positioned in an exposure area is provided. The method comprises obtaining projection data of the object by providing radiation to the exposure area and detecting at least some of the radiation exiting the object to form the projection data, performing a first reconstruction of the projection data to form at least one bootstrap image, obtaining first data based on information provided by the at least one bootstrap image, and performing a second reconstruction of the projection data based, at least in part, on the first data to form at least one second image.

Abstract: It is described a gain calibration for a two-dimensional X-ray detector (315), in which the gain coefficients for scattered radiation (307b) and direct radiation (307a) are measured or estimated separately. A weighed average may be applied on the appropriate scatter fraction. The scatter fraction depending gain calibration method produces less ring artifacts in X-ray images as compared to known gain calibration methods, which do not take into account the fraction of scattered radiation reaching the X-ray detector (315).

Abstract: The invention relates to a computed tomography method. The airgap associated with a projection direction is determined by determining, in the projection images, edge pixels which map object edges on a detector. By back-projecting the edge pixels in an object image space it is possible to determine an envelope polygon for an outline contour of the examination object. The width of the airgap associated with a specific projection direction can then be determined on the basis of the envelope polygon. Exact knowledge of the current airgap serves to improve the scattered radiation correction.

Abstract: A system for multi-mode breast x-ray imaging which comprises a compression arm assembly for compressing and immobilizing a breast for x-ray imaging, an x-ray tube assembly, and an x-ray image receptor is provided. The system is configured for a plurality of imaging protocols and modes.

Abstract: Scattered radiation is estimated by using a reduced image generated from a projection image, and the scattered radiation image of the projection image is acquired by enlargement processing. The scattered radiation correction of the projection image is executed by subtracting the obtained scattered radiation image from the projection image. In addition, when a primary X-ray image and a scattered radiation image in each projection direction are to be obtained by sequential approximation calculation, a primary X-ray image which has already been identified in an adjacent projection direction is used as a first estimated value (initially set value) in next sequential calculation.

Abstract: A system may include determination of a first scatter kernel based on a first energy, a material-equivalent radiological thickness and a first diameter, wherein the first scatter kernel is not a monotonically decreasing function of radial coordinate, determination of a second scatter kernel based on the first energy, the material-equivalent radiological thickness and a second diameter greater than the first diameter, determination of a third scatter kernel based on the first scatter kernel and the second scatter kernel, wherein the third scatter kernel is a monotonically decreasing function of radial coordinate, and estimation of scatter radiation within the projection image of the object based on the third scatter kernel.

Abstract: In a method for correction of scatter radiation errors in radiography and computer tomography, using flat panel detectors, initially an estimation of a scatter radiation distribution Scor(y,z) is undertaken, and a standard correction term ?pcor is subsequently calculated. Noise filtering of the standard correction term ?pcor with F(?pcor) is implemented and subsequently the noise-filtered standard correction term F(?pcor) is added to the logarithmized measured total projection data ps. The noise filtering can be implemented adaptively dependent on a previously-determined local noise variance. The method can be implemented in a radiography system and/or by a computer for generation and/or processing of projective and/or tomographic exposures, with a memory containing program codes causing the computer in operation to execute the steps of the method.

Abstract: A method is disclosed for scattered radiation correction in x-ray imaging devices having a number of x-ray sources that can be moved around an examination object in at least one scanning plane during a measurement pass. During the measurement pass, a number of x-ray projections are recorded at different projection angles with simultaneous use of the x-ray sources. In at least one embodiment of the present method, parameters characterizing an outer object contour are determined in the scanning plane from measured data of different x-ray projections.

Abstract: A grating with a large aspect ratio is disclosed, in particular to be used as an X-ray optical grating in a CT system and in particular produced by a lithography method. In at least one embodiment, the grating includes a multiplicity of recurring alternating grating webs and grating gaps with a height, and a multiplicity of filler beams, respectively arranged in the grating gaps with a spacing from one another in the direction of the gaps, which beams connect respectively adjacent grating webs over their height. In at least one embodiment, the grating webs and the grating gaps run from a first to a second side of the grating, and a filler beam has a width in the direction of the gaps and this width is at most 10% of the spacing between two adjacent filler beams. In at least one embodiment, the spacings between respective adjacent filler beams in a grating gap do not vary by more than 10% in the entire grating.

Abstract: A method for calibrating an imaging system includes coincident detecting scatter radiation events from a calibration source located within a bore of the imaging system. The scatter radiation events are subsequently used to compute calibration time offsets for each detector channel in the imaging system. Each detector channel is then calibrated with respective calibration time adjustments.

Abstract: An assembly for electron beam tomography affords continuous and simultaneous recording of two-dimensional slice images of an object in different irradiation planes with a high temporal and spatial resolution. Targets are penetrated by openings of a given width and with a regular arrangement in the circumferential direction. The openings in the targets are respectively situated on a path formed by the cross section of the shell of the electron beam cone with the respective target. The successive targets in the beam direction respectively are arranged with a small angular offset with respect to the optical axis to the respective target situated in front, and so an electron beam circulating along the shell of the electron beam cone successively irradiates the material webs between the openings of all targets with at least part of its cross section and an X-ray detector arc is arranged for each target in coplanar radial fashion in front of or behind the respective target.

Abstract: A data processing device, comprising a plurality of emitter antennas arranged on a movable data acquisition device and adapted to emit electromagnetic radiation including data acquired by the movable data acquisition device, a plurality of receiver antennas each adapted to receive the electromagnetic radiation emitted by each of the plurality of emitter antennas, and a data processing unit coupled to the plurality of receiver antennas and adapted to extract the data acquired by the movable data acquisition device from the electromagnetic radiation received by the plurality of receiver antennas.

Abstract: A computed tomography apparatus includes a gantry having a rotary portion and a stationary portion. At least one radiation source and at least one anti-scatter grid are mounted on the rotary portion of the gantry and positioned opposite each other. A detector device is mounted on the stationary portion of the gantry. The detector device may include a plurality of detector sensors arranged in the form of a generally circular ring surrounding the periphery of the rotary portion. Alternatively, the detector device may include a plurality of flat panel detectors arranged in a generally circular geometry.

Abstract: The invention relates to a method for speeding up the scattered radiation correction in a computed tomography system with a radiation source and a detector constructed in large-area format with a number of rows of detectors, by which an object is scanned from numerous projection angles, uses the measured values for the attenuation of the radiation in generating projection data which is postprocessed for the purpose of reconstructing tomographic views, in doing which a beam hardening correction is applied directly to the projection data, whereby according to the invention the scattered radiation correction is also applied directly to the projection data.

Abstract: Cone-beam CT scanners with large detector arrays suffer from increased scatter radiation. This radiation may cause severe image artefacts. An examination apparatus is provided which directly measures the scatter radiation and uses this measurement for a correction of the contaminated image data. The measurement is performed by utilizing a 1-dimensional anti-scatter-grid and an X-ray tube with an electronic focal spot movement. Image data is detected at a first position of a focal spot and scatter data is detected at a second position of the focal spot. The image data is corrected on the basis of the scatter data.

Abstract: A multi-emitter computed tomography scanner is disclosed, including a plurality of x-ray emitter/detector arrangement pairs arranged offset at an angle to one another. In at least one embodiment, the detector arrangements of the pairs are designed to be energy selective.

Abstract: A grid 3 arranged with a scattered radiation shielding plate 31 for each column is arranged at a front face of a radiation detector 2. The distance between the grid 3 and the radiation detector 2 is desirably a integral multiple of the height of the scattered radiation shielding plate 31. A true image signal of the pixel column including the shade is estimated from the image signal of the pixel column adjacent to the pixel column including the shade 41. The scattered radiation distribution is estimated from the image signals of the pixel column including the shade of the scattered radiation shielding plate and the image signals when considering that the shielding plate is not included in the shielded pixel. A clear diagnosis image without influence of scattered radiation is obtained by subtracting the estimated scattered radiation distribution from the estimated image signal distribution.

Abstract: The invention relates to a method for correcting x-ray scatter in projection radiography or in x-ray computer tomography, in which, for different observed objects, different scatter-correction convolution cores G are determined and in the examination of the respective objects object-specific scatter-correction convolution cores are applied to detector data which is created during the x-raying of these objects. The invention also relates to a projection radiography or x-ray computer tomography system which features programs in a processing system which executes the method described above when the system is operating.

Abstract: A computed tomography reconstruction method includes concurrently emitting radiation from at least two x-ray sources (14), switching the output state of each of the at least two x-ray sources (14) within a plurality of respective cross scatter sampling intervals (50, 52, 54, 56) and detecting with a corresponding one of the sets of detectors (24) cross scatter radiation emitted by the other at least two x-ray sources (14), wherein the cross scatter sampling intervals are angularly spaced over a plurality of frames to allow the at least two x-ray sources (14) to concurrently emit radiation throughout at least one frame, deriving scatter correction data for each set of detectors (24) from corresponding cross scatter samples, scatter correcting the projection data with corresponding scatter correction data, and reconstructing the scatter corrected projection data to generate at least one image.

Abstract: A system may include determination of a first scatter kernel based on a first energy, a material-equivalent radiological thickness and a first diameter, wherein the first scatter kernel is not a monotonically decreasing function of radial coordinate, determination of a second scatter kernel based on the first energy, the material-equivalent radiological thickness and a second diameter greater than the first diameter, determination of a third scatter kernel based on the first scatter kernel and the second scatter kernel, wherein the third scatter kernel is a monotonically decreasing function of radial coordinate, and estimation of scatter radiation within the projection image of the object based on the third scatter kernel.

Abstract: Scatter compensation is achieved in an X-ray imaging system by providing collimation means in the form of shutters (12) to collimate the primary X-ray beam (1) such that the radiation (8) transmitted through a subject (4) to be imaged is incident substantially centrally on the active part (14) of an image detector (3), so as to define an active border (14b), in respect of which scatter levels can be measured. An electrical signal (104) representative of the scatter level is subtracted from the electrical signal (7) representative of the radiation (8) transmitted through the subject, to obtain a scatter-compensated image signal (106).

Abstract: A method and an X-ray CT system are disclosed for producing tomographic pictures with the aid of an X-ray CT system including at least two X-ray sources arranged on a gantry with an angular offset to scan an examination object. In at least one embodiment of the method, in order to determine the scattered radiation distribution, pre-scanning is carried out in which the X-ray sources rotate about the examination object and the dose rate is modulated as a function of the rotation angle, no radiation dose is output over the majority of the revolution, at specific pre-scan angles a dose rate is produced briefly and individually in each case by the X-ray sources of the focus/detector systems, and the received scattered radiation is measured simultaneously by the detectors of the at least one other focus/detector system.

Abstract: A CT scanner with scatter correction device and a method for scatter correction are provided. The method of correcting CT images from artifacts caused by scattered radiation comprises affixing to the non-rotating frame of the CT gantry a plurality of shields for shielding some of the CT detector elements from direct X ray radiation, while allowing scattered radiation to arrive at said shielded elements; measuring scatter signals from said shielded elements, indicative of scattered radiation intensity; and correcting for scatter by subtracting scatter intensity values estimated from said measured scatter signals from signals measured by unshielded detector elements.

Abstract: The invention refers to X-ray devices, an X-ray detector and a method of correcting intensity signals. An X-ray detector then comprises for determining the intensity of X-rays, which comprise a proportion of primary radiation having an irradiation direction and a proportion of scattered radiation, at least a first sensor elements, which are each provided for converting the X-rays into first and second intensity signals, and a filter element, which is provided for decreasing the proportion of scattered radiation in the intensity of the X-rays, wherein the second sensor elements are arranged in irradiation direction behind the filter element and wherein the first sensor element fastened to the filter element is provided for determining the intensity of the X-rays before leaving the filter element. The proportion of the scattered radiation calculated from the measuring data of the first and second sensor elements is provided for correcting the second intensity signals for the following image generation.

Abstract: A method is disclosed for scattered radiation detection and/or for scattered radiation correction. In at least one embodiment, each radiation produced is provided with an individual temporal marker/variation of known magnitude, the change in the measured radiation being investigated for these typical temporal variations, and the fraction of the scattered radiation is inferred from the temporal variation found and, if appropriate, a corresponding correction is carried out. Furthermore, a CT system is disclosed, including a computer program that carries out at least one embodiment of the method.

Abstract: The present invention relates to a method for scattered radiation correction in X-ray imaging, and to an X-ray imaging system for carrying out the method. In the method, measurement signals t from an X-ray detector (9) are digitized and converted to logarithmic form, with these measurement signals t having been obtained by radiation through an examination object (10) by the X-ray detector (9). Correction values which have been obtained from a series development of a logarithm ln(1?s/t) are subtracted from the measurement signals that have been converted to logarithmic form, with this series development being terminated at the earliest after the first order, where s denotes a previously determined scattered radiation signal from radiation passed through the examination object (10). The method and the associated X-ray imaging system allow scattered radiation to be corrected for with increased accuracy, on the basis of measurement signals that had been converted to logarithmic form.

Abstract: A computed tomography reconstruction method includes concurrently emitting radiation from at least two x-ray sources (14), switching the output state of each of the at least two x-ray sources (14) within a plurality of respective cross scatter sampling intervals (50, 52, 54, 56) and detecting with a corresponding one of the sets of detectors (24) cross scatter radiation emitted by the other at least two x-ray sources (14), wherein the cross scatter sampling intervals are angularly spaced over a plurality of frames to allow the at least two x-ray sources (14) to concurrently emit radiation throughout at least one frame, deriving scatter correction data for each set of detectors (24) from corresponding cross scatter samples, scatter correcting the projection data with corresponding scatter correction data, and reconstructing the scatter corrected projection data to generate at least one image.

Abstract: A method for estimating a scattered ray intensity distribution in an X-ray CT apparatus, the method includes: irradiating a subject with X-rays; and configuring a cross-sectional image of the subject by detecting the X-rays passing through the subject, on the basis of a path length of a scattered ray passing through the subject, an X-ray absorption coefficient of the subject and an X-ray scattering probability of the subject, intensity of the scattered ray being calculated.