Patent application number | Description | Published |
20080205737 | Method and apparatus for the artifact-reduced detection of a 3D object in tomographic imaging - Incomplete data records owing to an object extent that stretches beyond the scanning field of view (SFOV) constitute a general problem in computed tomography. In these cases, parts of the object are to be reconstructed, for which only incomplete projections from an angular range of less than 180° are available. The application of iterative algorithms such as, for example, the algebraic reconstruction technique (ART) or the simultaneous algebraic reconstruction technique (SART) to this problem of truncated projections cannot lead to a satisfactory solution unless use is made of special boundary conditions. In order to regularize the reconstruction method, in at least one embodiment, information relating to the statistics of the attenuation values of the reconstructed object is also included in the form of the logarithmic probability function of the attenuation values. This information can be obtained from the regions of those image parts which are still completely contained in the SFOV, but nevertheless lie in the vicinity of the region where the object leaves the SFOV. Furthermore, the information can be used in an algebraic reconstruction method by adding a boundary condition term to the cost function to be minimized. Experiments indicate that taking account of this information leads to good estimates with reference to the object in the event of insubstantially truncated projections such as are customary in CT applications, for example. | 08-28-2008 |
20080232546 | Method for scattered radiation correction in x-ray imaging, and x-ray imaging system for this purpose - A method is disclosed for scattered radiation correction in X-ray imaging, and an X-ray imaging system is disclosed for carrying out the method. In at least one embodiment of the method, measurement signals t from an X-ray detector are digitized and converted to logarithmic form, with these measurement signals t having been obtained by radiation through an examination object by the X-ray detector. Correction values which have been obtained from a series development of a logarithm 1n(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. At least one embodiment of 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. | 09-25-2008 |
20080240340 | Method for scattered radiation correction in x-ray imaging devices - 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. In at least one embodiment, on the basis of one object contour section whose characterizing parameters have been determined from x-ray projections that lie in front of and/or behind the respective x-ray projection by a defined projection angle range, for each x-ray projection an assigned scattered radiation distribution is then retrieved or is interpolated in a database from scattered radiation distributions for object contour sections with similar characterizing parameters. This scattered radiation distribution is then used for the correction of the measured data for the respective x-ray projection. In at least one embodiment, the method enables scattered radiation correction in conjunction with operation of the x-ray sources. | 10-02-2008 |
20080285709 | Imaging method for variable pitch spiral CT and a CT machine for carrying out the method - An imaging method is disclosed for variable pitch spiral CT. In at least one embodiment, the method includes spiral scanning of an examination object lying on a patient table, with the aid of a beam emanating from at least one focus, and the aid of a detector arrangement of planar design lying opposite the focus, the detector arrangement supplying output data that represent the attenuation of the beams during passage through the examination object; filtering the output data; weighted back projection of the filtered output data; and visualizing a layer or a volume on a display unit on the basis of the back projected output data. In at least one embodiment, a non constant pitch of the spiral scanning is taken into account computationally during the back projection. In at least one embodiment, a CT machine is disclosed for carrying out the above named method. | 11-20-2008 |
20080292170 | Method for scattered radiation correction in an X-ray computed tomography system, and method for generating a tomographic display corrected for scattered radiation, and/or an X-ray computed tomography system - A method is disclosed for scattered radiation correction in an X-ray computed tomography system having at least two tube-detector systems. It is provided, according to at least one embodiment, to make use of a data record that includes data projections required for the reconstruction and a prescribed number of first scattered radiation projections. Respective scattered radiation components for the scattered radiation correction of all data projections are determined on the basis of the first scattered radiation projections and second scattered radiation projections determined therefrom. | 11-27-2008 |
20080310582 | X-Ray System for the Creation of Diagnostic X-Ray Images Using Contrast Media - An x-ray system is disclosed including a selector for finding an optimum combination between the contrast medium and the energy spectrum of an x-radiation for a scan to optimize the noise-to-contrast ratio. A method for creating X-ray images is also provided. The x-ray images are created with the aid of contrast media by taking into account an optimal combination between the contrast medium and the energy spectrum of an X-radiation used for a scan. A method for the use of a lanthanide-containing complex to produce a contrast medium for optimizing the combination between the contrast medium and the radiation to obtain a maximum contrast-to-noise ratio in an X-ray image is also provided. | 12-18-2008 |
20090010518 | METHOD FOR RECONSTRUCTION OF COMPUTED TOMOGRAPHY REPRESENTATIONS FROM X-RAY CT DATA SETS OF AN EXAMINATION SUBJECT WITH SPIRAL SCANNING - The image reconstruction is implemented along theoretical π-lines, wherein the theoretical π-lines not only lead to interpolated detector data but also can emanate from interpolated source positions. Interpolation thus occurs both at the detector and at the source. | 01-08-2009 |
20090124892 | Method for measuring cardiac perfusion in a patient and CT system for carrying out the method - A method and a CT system are disclosed for measuring the perfusion in vessels and/or muscles of the heart (cardiac perfusion) in a patient. In at least one embodiment of the method the patient receives a contrast agent bolus, the patient is scanned for a scan period of a plurality of cardiac cycles in a scan field of a CT system controlled by the cardiac rhythm, a plurality of CT image data is reconstructed from projection data of a particular cardiac phase from respectively one cardiac cycle, and the temporal profile of the absorption values at at least one location in the heart is determined and displayed on the basis of a plurality of CT image data at successive times. At least one embodiment of the invention is distinguished by the fact that during the examination, the patient is repeatedly and alternately moved in opposite directions along a system axis of the CT system such that his cardiac region passes through the scan field at a cardiac phase range and the cardiac region is completely scanned spirally. | 05-14-2009 |
20090129540 | Correcting transverse scattering in a multi-emitter CT scanner - 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. | 05-21-2009 |
20090141857 | Method for post-processing raw detector signals, a computer program product, a computer readible medium and a radiation detection device - Methods for post-processing raw detector signals of an x-ray or gamma detector are disclosed. According to at least one embodiment of the invention, raw detector signals are filtered, an associated filtered signal is determined at least for a subset of the raw detector signals, and those filtered signals whose signal value is less than zero are then respectively replaced by a signal value greater than zero. | 06-04-2009 |
20090324045 | Method of reconstructing CT image data - A method is disclosed for reconstructing CT image data. In at least one embodiment, the method includes providing measured CT projection data p based on the CT projection data p, reconstructing first CT image data f | 12-31-2009 |
20100014737 | Method for generating image data relating to a virtually prescribable x-ray tube voltage from first and second CT image data - A method for generating image data relating to a virtually prescribable X-ray tube voltage U | 01-21-2010 |
20100046819 | Method and image reconstruction device for generating computed tomography image data - A method is disclosed for generating computed tomography image data of a volume of interest from X-ray CT data sets generated by a computed tomography system during scanning of an examination subject on a helical path rotating around a longitudinal system axis in the infeed direction. In at least one embodiment, at least two volume-based reconstructions of the volume of interest are performed by way of differential back-projection over surfaces constituted by different groups of M-lines, followed in each case by an inverse Hilbert transformation, the groups of M-lines for the reconstructions being selected from different of the following M-line subsets:
| 02-25-2010 |
20100074397 | Method for detecting X-ray radiation and X-ray system - A method is disclosed for detecting X-ray radiation from an X-ray emitter. In at least one embodiment of the method, an electric pulse with a pulse amplitude characteristic of the energy of a quantum is generated when a quantum of the X-ray radiation impinges on a sensor, wherein a number of threshold energies are predetermined. When the pulse amplitude corresponding to the respective energy is exceeded, a signal is emitted each time the pulse amplitude corresponding to a respective threshold energy is exceeded. At least one embodiment of the method permits reliable and high-quality imaging, even in image regions with high X-ray quanta rates. To this end, at least one of the threshold energies is predetermined such that it is higher than the maximum energy of the X-ray spectrum emitted by the X-ray emitter. | 03-25-2010 |
20100111247 | Computed tomography device with active adaptation of the measuring electronics - A computed tomography device (CT device) includes a user interface, via which the standard settings characterizing the CT measurement can be performed. At the same time, in a method and a computed tomography device for carrying out this method, filtering behavior of the filter electronics is adapted to the configuration of the standard settings by the system computer. | 05-06-2010 |
20100189213 | CORRECTING TRANSVERSE SCATTERING IN A MULTI-EMITTER CT SCANNER - 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. | 07-29-2010 |
20100195787 | METHOD AND DEVICE FOR GENERATING A CT IMAGE WITH A HIGH TIME RESOLUTION - A method and a device are disclosed for generating a CT image with a high time resolution using a computed tomography scanner which has at least two recording systems which are operated at different X-ray energy spectra. In at least one embodiment of the process, CT images are firstly reconstructed in each case from a semi-rotation with the two recording systems, with irradiated lengths of the contrast agent-enriched structures and the soft tissue being calculated therefrom. Subsequently, a common X-ray energy is assumed and artificial measurement data records are calculated therefor, using the knowledge of the irradiated lengths for both recording systems at the same common X-ray energy. The artificial measurement data of respectively a quarter-rotation per recording system is then used to calculate the final CT image with a high time resolution. The method affords the use of dual-energy scans without losing the high time resolution available in dual-source systems. | 08-05-2010 |
20100246751 | METHOD AND IMAGE RECONSTRUCTION DEVICE FOR RECONSTRUCTING IMAGE DATA - A method and an image reconstruction device are disclosed for reconstructing image data on the basis of input projection data obtained via an X-ray computerized tomography system. A target convolutional kernel is selected, which, when reconstructing image data from the input projection data using simple filtered back projection, would lead to target image characteristics. Image data is then reconstructed using an iterative reconstruction method of at least one embodiment. In at least one embodiment, the method includes a) reconstructing image data of a first iterative stage from the input projection data, b) generating synthetic projection data on the basis of the image data of the current iterative stage, c) forming difference projection data on the basis of the input projection data and the synthetic projection data, d) generating residue image data from the difference projection data, e) combining the residue image data with the image data of the current iterative stage to form image data of an additional iterative stage, wherein the image data of the current iterative stage is subjected to filtering before or during combination with the residue image data by using a regularization convolutional kernel which is determined on the basis of the selected target convolutional kernel, and f) repeating b) to e) until a termination condition occurs. | 09-30-2010 |
20100246918 | ITERATIVE EXTRA-FOCAL RADIATION CORRECTION IN THE RECONSTRUCTION OF CT IMAGES - A method is disclosed for reconstruction of image data of an object under examination from measurement data, with the measurement data having been recorded during a rotating movement of a radiation source of a computed tomography system around the object under examination. The radiation source emits focal and extra-focal radiation. In at least one embodiment of the method, the image data is determined from the measurement data by use of an iterative algorithm. A variable is used in the iterative algorithm which contains a distribution of the extra-focal radiation. | 09-30-2010 |
20110033097 | CT IMAGE RECONSTRUCTION FOR IMPROVING TEMPORAL RESOLUTION IN CARDIO CT - A method is disclosed for reconstructing image data of a moving examination object from measurement data, wherein the measurement data was captured in the course of a relative rotational movement between a radiation source of a computed tomography system and the examination object. In at least one embodiment of the method, a first image of the examination object is calculated from a complete measurement data record of the measurement data for an image reconstruction and a second image of the examination object is calculated from an incomplete measurement data record of the measurement data for an image reconstruction. Frequency splitting of the first and second images takes place respectively in at least one low-frequency and one higher-frequency component and the image data of the second image is supplemented in the low-frequency component with image data of the low-frequency component of the first image. In a further processing step the second image thus supplemented is improved using the first image, in that errors due to the incompleteness of the measurement data record of the second image are reduced. | 02-10-2011 |
20110052021 | Precise image reconstruction of spiral CT images at optional pitch values - At least one embodiment of the invention relates to a method for the reconstruction of image data of an examined object from measuring data, wherein the measuring data were detected by a detector within and outside of its Tam-Danielsson window during a relative spiral movement between a radiation source of a computer tomography system and the examined object. As a result of the spiral movement, the measuring data outside of the Tam-Danielsson contain interruptions. A mathematically precise first reconstruction of first image data is realized in at least one embodiment based on the measuring data by using only measuring data from the Tam-Danielsson window. A mathematically precise second reconstruction is furthermore realized of second image data from the measuring data in at least one embodiment, using at least among other things measuring data from outside of the Tam-Danielsson window, wherein the interruption of the measuring data is compensated for by using existing measuring data and/or the first image data and/or other image data obtained from existing measuring data. Finally, the first image data and the second image data are combined. | 03-03-2011 |
20110121191 | CIRCUIT ARRANGEMENT FOR COUNTING X-RAY RADIATION X-RAY QUANTA BY WAY OF QUANTA-COUNTING DETECTORS, AND ALSO AN APPLICATION-SPECIFIC INTEGRATED CIRCUIT AND AN EMITTER-DETECTOR SYSTEM - A circuit arrangement of a quanta-counting detector with a multiplicity of detector elements is disclosed, wherein the X-ray quanta registered in each detector element generate a signal profile. In at least one embodiment, the circuit arrangement, in each detector element, includes: at least one first comparator with a first energy threshold lying in the energy range of the measured X-ray quanta and at least one second comparator with a second energy threshold lying above the energy range of the measured X-ray quanta, the at least one first and second comparators being connected to the detector element. Further, the at least two comparators have a logical interconnection, wherein at least a first comparator and a second comparator are connected to the inputs of an XOR gate, and each XOR gate connected to a first comparator is connected to precisely one edge-sensitive counter. Further, in at least one embodiment, an application-specific integrated circuit (ASIC) and an emitter-detector system of an X-ray CT system, including at least one circuit arrangement, are disclosed. | 05-26-2011 |
20110188723 | CT Image Reconstruction In The Extended Field Of View - A method is disclosed for reconstructing image data of an examination subject from measured data, wherein the measured data was acquired in the course of a relative rotational movement between a radiation source of a computed tomography system and the examination subject. A limited area between the radiation source and a detector represents a field of view in respect of which measured data can be acquired, and parts of the examination subject were located at least temporarily outside the field of view in the course of the measured data acquisition. In at least one embodiment, first image data is reconstructed from the measured data, and a boundary of the examination subject is determined with the aid of the first image data. The first image data is subsequently modified using the determined boundary, and projection data is calculated from the modified first image data. The measured data is modified using the projection data, and finally second image data is reconstructed from the modified measured data. | 08-04-2011 |
20110188724 | CT MEASUREMENT WITH MULTIPLE X-RAY SOURCES - A method is disclosed for reconstructing image data of an examination object from measurement data of a computed tomography system, the examination object having been irradiated simultaneously by a number of X-ray sources while the measurement data was being acquired so that different projections of the examination object associated with the number of X-ray sources were acquired simultaneously for each detector element. In at least one embodiment, different iteration images of the examination object are determined one after the other from the measurement data by way of an iterative algorithm, a computation operation being employed with the iterative algorithm, which is applied to the iteration images and takes the presence of the number of X-ray sources into account. | 08-04-2011 |
20110293159 | ITERATIVE CT IMAGE RECONSTRUCTION WITH A FOUR-DIMENSIONAL NOISE FILTER - A method is disclosed for reconstruction of image data of an object under examination from measurement data, with the measurement data having been captured during a relative rotational movement between a radiation source of a computed tomography system and the object under examination. In at least one embodiment, first image data is computed by the measurement data being modified to obtain a specific gray value characteristic of the first image data to be reconstructed and the first image data is computed by way of an iterative algorithm using the modified measurement data. Second image data is also computed by a series of chronologically-consecutive images being reconstructed and processing being carried out on the series of images to reduce temporal noise. Finally a combination of the first and the second image data is carried out. | 12-01-2011 |
20120069950 | METHOD AND X-RAY DEVICE FOR CREATING AN X-RAY PROJECTION IMAGE - A method and an X-ray device are disclosed for creating an X-ray projection image of a three-dimensional object under examination and for displaying the projection image. In at least one embodiment, pixel images are recorded from two different perspectives and a projection image is created by overlaying the two pixel images, wherein perspective-related offset of the mapping image pixels is taken into account, pixel-by-pixel, in relation to an imaging surface in the object under examination. | 03-22-2012 |
20120158811 | Method For Transforming Input Data And Medical Device - A method is disclosed for transmitting measurement data from a transmitter system to a receiver system by way of a transmission link of a medical device. In an embodiment, the measurement data, as input data of a transformation method, is transformed to output values and, after transmission, back transformed again, the values of the input data lying between a maximum value and a minimum value and an assignment function being used for compression purposes, to allocate an output value to every value of the input data, a root function being used as the assignment function for at least some of the values. | 06-21-2012 |
20120195483 | Method And Computer System For The Reduction Of Artifacts In Reconstructed CT Image Datasets - A method and computer system are disclosed with software for artifact reduction in CT image datasets for spiral scans from a CT system with an inclined gantry. In at least one embodiment, for each of at least two positions of the center of rotation, which is moved during the spiral scan, the removal of annular artifacts is carried out around these positions, during which the position concerned is used as the center point of the annular artifacts to be removed. | 08-02-2012 |
20120213424 | METHOD AND COMPUTER SYSTEM FOR SCATTERED BEAM CORRECTION IN A MULTI-SOURCE CT - A method and a computer system are disclosed for scattered beam correction in a CT examination of an object in a multi source CT. In at least one embodiment, the method includes generating original projection data records; reconstruction of the object with the original projection data records of at least one detector; determining the scattered radiation generated by each emitter exclusively in the direction of the original beams of the at least one other emitter relative to its opposing detector; generating corrected projection data records by removing the calculated scattered radiation from the original projection data records; reconstruction of the object with the corrected projection data records, and implementing a further iteration of the method when determining the scattered radiation or issuing the reconstruction result if at least one predetermined abort criterion applies. | 08-23-2012 |
20120219106 | FILTER FOR AN X-RAY DEVICE, AND X-RAY DEVICE EMBODYING SUCH A FILTER - A filter for an x-ray device to shape an intensity profile of x-ray radiation emanating from an x-ray source of the device has a filter body made of a material that attenuates x-ray radiation. The filter body is designed with a propeller shape and has two blades connected by an axle of the filter. The filter body is rotatable around the axle, which is permeable to the x-ray radiation. The x-ray device embodies at least one such filter. | 08-30-2012 |
20130208854 | COMPUTED TOMOGRAPHY DEVICE AND METHOD FOR OPERATING A COMPUTED TOMOGRAPHY DEVICE - A method is disclosed for operating a computed tomography device including an x-ray source embodied to emit a fan-type beam bundle and a detector arrangement interacting therewith and including a plurality of detector elements. An embodiment of the method provides that an integration time provided to read out a detector element is dependent on the position of the detector element within the detector arrangement, wherein with a detector element which detects x-rays which penetrate the isocenter lying between the c-ray source and the detector arrangement, a longer integration time is provided, than with a detector element which detects x-rays which penetrate an examination volume which is further away from the isocenter. | 08-15-2013 |
20130259344 | METHOD FOR RECONSTRUCTING CT IMAGES WITH SCATTER CORRECTION, IN PARTICULAR FOR DUAL-SOURCE CT DEVICES - A method is disclosed for reconstructing image data of an examination object from measurement data, wherein the measurement data were acquired in the course of a relative rotational movement between a radiation source of a computed tomography system and the examination object. First image data of the examination object are reconstructed from the measurement data. Scatter signals are calculated from the first image data using a scattered radiation model, wherein the scattered radiation model specifies an angle-dependent scatter distribution for a scatter point as a function of a line integral corresponding to an attenuation integral of a scattered beam from the scatter point to a specific detector element. The calculated scatter signals are used for correcting the measurement data, and second image data are reconstructed using the corrected measurement data. | 10-03-2013 |
20140126688 | X-RAY DETECTOR SYSTEM FOR A COMPUTED TOMOGRAPHY SCANNER AND COMPUTED TOMOGRAPHY DEVICE - For improved sampling, an x-ray detector system for a computed tomography scanner is provided. In an embodiment, the x-ray detector system includes at least one detector row which includes a plurality of detector modules each having a plurality of detector elements. Along the at least one detector row, a first portion of the detector elements is arranged in a grid at a first grid spacing in relation to its respective neighboring detector elements, and a second portion of the detector elements is arranged in a grid at a second grid spacing in relation to its respective neighboring detector elements. | 05-08-2014 |
20140169649 | CT IMAGE RECONSTRUCTION WITH EDGE-MAINTAINING FILTERING - A method is disclosed for reconstructing image data of an examination object from measurement data, wherein the measurement data were captured previously during a relative rotational movement between a radiation source of a computed tomography system and the examination object. Filtered measurement data are calculated from the measurement data. First image data are calculated from the measurement data. Edge information is obtained from the first image data, wherein the edge information, depending on position, specifies strength and direction of edges within the first image data. New measurement data are calculated using the edge information by mixing the measurement data and the filtered measurement data and second image data are calculated from the new measurement data. | 06-19-2014 |