Patent application number | Description | Published |
20080267476 | METHOD AND SYSTEM FOR RECONSTRUCTING IMAGE VOLUMES FROM HELICAL SCAN ACQUISITIIONS - A method and computer-readable medium for reconstructing an image volume of an object scanned in helical mode is provided. The method and computer-readable medium include obtaining one or more helical views corresponding to an image volume of an object and determining a plurality of discretized focal lengths within an imaging plane of the reconstructed field of view comprising the image volume. The method then comprises generating a plurality of circular scan sinograms for the plurality of discretized focal lengths. The plurality of circular scan sinograms are generated by interpolating the helical views. The method then comprises selecting one or more circular scan sinograms from the plurality of circular scan sinograms, based on the plurality of discretized focal lengths, wherein the selection is performed within a backprojection operation, for one or more image points within the imaging plane, over one or more circular views. The method then comprises using one or more of the selected circular scan sinograms, in the backprojection of one or more of the image points over one or more of the circular views. The method finally comprises performing a backprojection for all the image points over all the circular views to generate a reconstructed image of the object. | 10-30-2008 |
20080273666 | SYSTEM AND METHOD OF DENSITY AND EFFECTIVE ATOMIC NUMBER IMAGING - A system and method of density and effective atomic number imaging include a computer programmed to acquire projection data from the detector of an unknown material at the time of projection data acquisition. The computer is also programmed to generate a density image for the unknown material based on a calibration of two or more known basis materials and to generate an effective atomic number (Z) for the unknown material based on the calibration of two or more known basis materials and based on a function arctan of a ratio of atomic numbers of the two or more known basis materials. The density and effective atomic number images are stored to a computer readable storage medium. | 11-06-2008 |
20090052612 | SYSTEM AND METHOD OF OPTIMIZING A MONOCHROMATIC REPRESENTATION OF BASIS MATERIAL DECOMPOSED CT IMAGES - A system and method of a diagnostic imaging system includes a high frequency electromagnetic energy source that emits a beam of high frequency electromagnetic energy toward an object to be imaged, a detector that receives high frequency electromagnetic energy emitted by the high frequency electromagnetic energy source and attenuated by the object, a data acquisition system (DAS) operably connected to the detector, and a computer operably connected to the DAS. The computer is programmed to obtain CT scan data with two or more incident energy spectra, decompose the obtained CT scan data into projection CT data of two or more basis materials, reconstruct linearly weighted projections of the two or more basis materials, determine an optimized energy for the two or more basis materials within a region-of-interest (ROI), and form a monochromatic image of the projection CT data at the optimized energy using the two or more basis material projections. | 02-26-2009 |
20090052621 | METHOD AND APPARATUS FOR BASIS MATERIAL DECOMPOSITION WITH K-EDGE MATERIALS - A diagnostic imaging system includes a high frequency electromagnetic energy source that emits a beam of high frequency electromagnetic energy toward an object to be imaged, a detector that receives high frequency electromagnetic energy emitted by the high frequency electromagnetic energy source, and a data acquisition system (DAS) operably connected to the detector. A computer is operably connected to the DAS and is programmed to generate corresponding sets of projection values for three or more energy spectra through employment of attenuation coefficients of three or more basis materials to simulate responses of the diagnostic imaging system to a plurality of lengths of the three or more basis materials wherein the three or more basis materials comprise two or more non K-edge basis materials and one or more K-edge basis materials. | 02-26-2009 |
20090092219 | METHOD AND APPARATUS FOR PERFORMING DUAL-SPECTRUM CT WITH FAST KV MODULATION AT MULTIPLE-VIEW INTERVALS - A CT system includes a rotatable gantry having an opening for receiving a subject to be scanned, a rotatable gantry having an opening for receiving a subject to be scanned, an x-ray source configured to project x-rays having multiple energies toward the subject, and a generator configured to energize the x-ray source to a first voltage and configured to energize the x-ray source to a second voltage, the first voltage distinct from the second voltage. The system further includes a controller configured to cause the generator to energize the x-ray source to the first voltage for a first duration, acquire imaging data for at least one view during at least the first duration, after the first duration, cause the generator to energize the x-ray source to the second voltage for a second duration, and acquire imaging data for two or more views during at least the second duration. | 04-09-2009 |
20090129538 | METHOD AND SYSTEM OF ENERGY INTEGRATING AND PHOTON COUNTING USING LAYERED PHOTON COUNTING DETECTOR - A diagnostic imaging system includes an x-ray source that emits a beam of x-ray energy toward an object to be imaged and an energy discriminating (ED) detector that receives the x-ray energy emitted by the x-ray energy source. The ED detector includes a first layer having a first thickness, wherein the first layer comprises a semiconductor configurable to operate in at least an integrating mode and a second layer having a second thickness greater than the first thickness, and configured to receive x-rays that pass through the first layer. The system further includes a data acquisition system (DAS) operably connected to the ED detector and a computer that is operably connected to the DAS. The computer is programmed to identify saturated data in the second layer and substitute the saturated data with non-saturated data from a corresponding pixel in the first layer. | 05-21-2009 |
20090147910 | SYSTEM AND METHOD FOR ENERGY SENSITIVE COMPUTED TOMOGRAPHY - An energy-sensitive computed tomography system is provided. The energy-sensitive computed tomography system includes an X-ray source configured to emit an X-ray beam resulting from electrons impinging upon a target material. The energy-sensitive computed tomography system also includes an object positioned within the X-ray beam. The energy-sensitive computed tomography system further includes a detector configured to receive a transmitted beam of the X-rays through the object. The energy-sensitive computed tomography system also includes a filter having an alternating pattern disposed between the X-ray source and the detector, the filter configured to facilitate measuring projection data that can be used to generate low-energy and high-energy spectral information. | 06-11-2009 |
20090161814 | METHOD FOR CALIBRATING A DUAL -SPECTRAL COMPUTED TOMOGRAPHY (CT) SYSTEM - A method for calibrating and reconstructing material density images in a dual-spectral computed tomography (CT) system | 06-25-2009 |
20090161939 | SYSTEM AND METHOD FOR EXTRACTING FEATURES OF INTEREST FROM AN IMAGE - A technique is provided for extracting one or more features of interest from one or more projection images. The technique includes accessing projection images comprising at least one feature of interest enhanced by a contrast agent, generating a contrast agent null image based on the projection images, generating a bone mask based on the contrast agent null image, and generating a bone extracted image based on the bone mask. | 06-25-2009 |
20090214095 | SYSTEM AND METHOD TO OBTAIN NOISE MITIGTED MONOCHROMATIC REPRESENTATION FOR VARYING ENERGY LEVEL - In dual energy CT, through basis material decomposition (BMD), a pair of density images can be reconstructed. The noises in this image pair are negatively correlated due to the BMD process. A technique is presented for obtaining the monochromatic images at desired energy levels with reduced correlation noise. The technique includes obtaining a plurality of optimum attenuation coefficients for an energy level, selecting a desired energy level, obtaining a plurality of desired attenuation coefficients for the desired energy level, computing a scaling factor for a corresponding noise component based on the optimum attenuation coefficients and the desired attenuation coefficients, and generating a monochromatic image based upon the scaling factor. | 08-27-2009 |
20090304249 | MATERIAL COMPOSITION DETECTION FROM EFFECTIVE ATOMIC NUMBER COMPUTATION - A technique is provided for computing an atomic number of materials forming an object imaged by a radiological modality. The method includes accessing a first monochromatic image and a second monochromatic image of the object, the first monochromatic image acquired at a first energy level and the second monochromatic image acquired at a second energy level. A ratio of the mass attenuation coefficients between the first monochromatic image and the second monochromatic image may be obtained. The atomic number for a material of the object may be computed based upon the ratio of mass attenuation coefficients. | 12-10-2009 |
20100020921 | SYSTEM AND METHOD FOR GENERATING COMPUTED TOMOGRAPHY IMAGES - A computed tomographic imaging system is provided for generating computed tomography images. The computed tomographic system includes a processor configured to access image data encoding X-ray projections at a detector position and a plurality of X-ray source beam focal spot positions and to align pixel values for the projections in a direction of deviation of the positions. The processor is also configured to determine a correction factor for at least one of the projections based upon the aligned pixel values and upon a sum of the projections and to correct the pixel values for the at least one of the projections based upon the correction factor. | 01-28-2010 |
20100104062 | SYSTEM AND METHOD OF FAST KVP SWITCHING FOR DUAL ENERGY CT - A CT system includes a rotatable gantry having an opening for receiving an object to be scanned and an x-ray source coupled to the gantry and configured to project x-rays through the opening. The x-ray source includes a target, a first cathode configured to emit a first beam of electrons toward the target, a first gridding electrode coupled to the first cathode, a second cathode configured to emit a second beam of electrons toward the target, and a second gridding electrode coupled to the second cathode. The system includes a generator configured to energize the first cathode to a first kVp and to energize the second cathode to a second kVp, and a detector attached to the gantry and positioned to receive x-rays that pass through the opening. The system also includes a controller configured to apply a gridding voltage to the first gridding electrode to block emission of the first beam of electrons toward the target, apply the gridding voltage to the second gridding electrode to block emission of the second beam of electrons toward the target, and acquire dual energy imaging data from the detector. | 04-29-2010 |
20100128948 | FORWARD PROJECTION FOR THE GENERATION OF COMPUTED TOMOGRAPHY IMAGES AT ARBITRARY SPECTRA - The present technology relates to the generation of a CT image under an arbitrary energy spectrum based on the results of a dual energy scan. In certain embodiments, a dual energy scan is conducted of an object and material basis decomposition is used to decompose the scanned object into two basis materials with known attenuation properties resulting in material density images. Along with knowledge of other imaging system information, forward projection is done under an arbitrary kV spectrum to generate an image as if the scanned object was scanned under this different kV spectrum. This prevents users from conducting unnecessary additional scans. | 05-27-2010 |
20110052022 | SYSTEM AND METHOD OF DATA INTERPOLATION IN FAST KVP SWITCHING DUAL ENERGY CT - A CT system includes a rotatable gantry having an opening for receiving an object to be scanned, an x-ray source coupled to the gantry and configured to project x-rays through the opening, a generator configured to energize the x-ray source to a first kVp and to a second kVp to generate the x-rays, and a detector having pixels therein, the detector attached to the gantry and positioned to receive the x-rays. The system includes a computer programmed to acquire a first view dataset and a second view dataset with the x-ray source energized to the first kVp, interpolate the first and second view datasets to generate interpolated pixels in an interpolated view dataset at the first kVp, using at least two pixels from each of the first and second view datasets to generate each interpolated pixel in the interpolated view dataset, and generate an image of the object using the interpolated view dataset. | 03-03-2011 |
20110142194 | SYSTEM AND METHOD OF ACQUIRING MULTI-ENERGY CT IMAGING DATA - A CT system includes a rotatable gantry having an opening for receiving an object to be scanned, and a controller configured to apply a first kVp for a first time period, apply a second kVp for a second time period, wherein the second time period is different from the first time period, acquire a first asymmetric view dataset during at least a portion of the first time period, acquire a second asymmetric view dataset during at least a portion of the second time period, and generate an image using the acquired first and second asymmetric view datasets. | 06-16-2011 |
20110142312 | SYSTEM AND METHOD OF MITIGATING LOW SIGNAL DATA FOR DUAL ENERGY CT - A CT system includes a rotatable gantry having an opening for receiving an object to be scanned, and a controller configured to obtain kVp projection data at a first kVp, obtain kVp projection data at a second kVp, extract data from the kVp projection data obtained at the second kVp, add the extracted data to the kVp projection data obtained at the first kVp to generate mitigated projection data at the first kVp, and generate an image using the mitigated projection data at the first kVp and using the projection data obtained at the second kVp. | 06-16-2011 |
20110150183 | DUAL-ENERGY IMAGING AT REDUCED SAMPLE RATES - The present disclosure relates to the generation of dual-energy X-ray data using a data sampling rate comparable to the rate utilized for single-energy imaging. In accordance with the present technique a reduced kVp switching rate is employed compared to conventional dual-energy imaging. Full angular resolution is achieved in the generated images. | 06-23-2011 |
20110158381 | 2D REFLECTOR AND COLLIMATOR STRUCTURE AND METHOD OF MANUFACTURING THEREOF - A two dimensional collimator assembly and method of manufacturing thereof is disclosed. The collimator assembly includes a wall structure constructed to form a two dimensional array of channels to collimate x-rays. The wall structure further includes a first portion positioned proximate the object to be scanned and configured to absorb scattered x-rays and a second portion formed integrally with the first portion and extending out from the first portion away from the object to be scanned. The first portion of the wall structure has a height greater than a height of the second portion of the wall structure. The second portion of the wall structure includes a reflective material coated thereon in each of the channels forming the two dimensional array of channels. | 06-30-2011 |
20110158498 | NOISE REDUCTION METHOD FOR DUAL-ENERGY IMAGING - A method is provided that includes acquiring a first set of image data from X-rays produced at a first energy level and a second set of image data from X-rays produced at a second energy level. The method includes generating a first noise mask for a first basis material and a second noise mask for a second basis material and removing pixels corresponding to cross contaminating structural information from the first noise mask and the second noise mask. The method includes processing a first materially decomposed image generated from the first set of image data and the second set of digital data using the second noise mask after removal of the cross contaminating structural information and processing a second MD image generated from the first set of image data and the second set of digital data using the first noise mask after removal of the cross contaminating structural information. | 06-30-2011 |
20110211667 | DE-POPULATED DETECTOR FOR COMPUTED TOMOGRAPHY AND METHOD OF MAKING SAME - A system, method, and apparatus includes a computed tomography (CT) detector array having a central region with a plurality of central region detecting cells configured to acquire CT data of a first number of slices during a scan, a first wing along a first side of the central region, and a second wing along a second side of the central region opposite the first side. The first wing includes a plurality of first wing detecting cells configured to acquire CT data of a second number of slices during the scan. The second wing includes a plurality of second wing detecting cells configured to acquire CT data of a third number of slices during the scan. The second and third number of slices are less than the first number of slices. The first wing detecting cells are of a different type than the central region detecting cells. | 09-01-2011 |
20110243413 | METHOD AND SYSTEM FOR IMAGE DATA ACQUISITION - A technique for acquiring desired image data in an imaging system comprising at least one radiation source and a detector is described. Initially, preliminary image data corresponding to an object may be acquired. Further, at least one parameter associated with the radiation source and corresponding to a particular view angle of the radiation source may be determined based on the preliminary image data and a priori information. Similarly, at least one parameter associated with the detector and corresponding to the particular view angle may be determined based on a priori information and the preliminary image data. Efficient operating modes of the radiation source and the detector corresponding to the particular view angle may be selected based on the determined parameters to achieve a desired system performance. Subsequently, the final image data may be acquired using the selected operating modes of the radiation source and the detector. | 10-06-2011 |
20110249879 | CT SPECTRAL CALIBRATION - The present disclosure relates to the performing spectral calibration of a CT imaging system. In accordance with certain embodiments, spectral calibration phantoms are scanned while positioned on a table in the imaging volume of the CT imaging system. The scans of the calibration phantoms, in conjunction with air sans performed on the CT imaging system, are used to derive information about the deviation of the measured phantom scans from an ideal. The deviation information is in turn used to derive spectral calibration vectors that may be used with the CT imaging system. | 10-13-2011 |
20110280363 | METHOD OF FAST CURRENT MODULATION IN AN X-RAY TUBE AND APPARATUS FOR IMPLEMENTING SAME - An X-ray tube includes a target and a cathode assembly. The cathode assembly includes a first filament configured to emit a first beam of electrons toward the target, a first gridding electrode coupled to the first filament, a second filament configured to emit a second beam of electrons toward the target, and a second gridding electrode coupled to the second filament. | 11-17-2011 |
20120014502 | ASYMMETRIC DE-POPULATED DETECTOR FOR COMPUTED TOMOGRAPHY AND METHOD OF MAKING SAME - A computed tomography (CT) detector array includes a central region substantially symmetric about a central axis thereof and includes a first plurality of x-ray detector cells configured to acquire CT data from a first number of detector rows during a scan, wherein the central axis is in a channel direction of the CT detector array and transverse to a slice direction of the CT detector array. A first wing is coupled to a first side of the central region, and a second wing is coupled to a second side of the central region opposite the first side. The first and second wings include respective second and third pluralities of x-ray detector cells and are each configured to acquire CT data from a number of detector rows that is less than the first number of detector rows. The CT detector array is asymmetric about the central axis of the central region. | 01-19-2012 |
20120069952 | SYSTEM AND METHOD OF SPECTRAL CALIBRATION AND BASIS MATERIAL DECOMPOSITION FOR X-RAY CT SYSTEMS - An imaging system includes an x-ray source that emits a beam of x-rays toward an object, a detector that receives high frequency electromagnetic energy attenuated by the object, a data acquisition system (DAS) operably connected to the detector, and a computer operably connected to the DAS. The computer is programmed to compute detector coefficients based on a static low kVp measurement and a static high kVp measurement, capture incident spectra at high and low kVp during fast kVp switching, compute effective X-ray incident spectra at high and low kVp during fast kVp switching using the captured incident spectra, scan a water phantom and normalize the computed detector coefficients to water, adjust the computed effective X-ray incident spectra based on the normalized detector coefficients, compute basis material decomposition functions using the adjusted X-ray incident spectra, and generate one or more basis material density images using the computed basis material decomposition functions. | 03-22-2012 |
20120134561 | METHOD AND SYSTEM FOR CORRELATED NOISE SUPPRESSION IN DUAL ENERGY IMAGING - Methods and systems for correlated noise suppression are presented. The present correlated noise suppression technique estimates a correlation direction between noise values in a first and a second MD image corresponding to a first and a second basis material, respectively. The two MD images are diffused using the estimated correlation direction to generate a first and a second diffused image. Further, first and second noise masks are generated by subtracting the diffused image from the corresponding MD image. Edges in the first and the second MD images are processed with the first and second noise masks, respectively to generate a final first noise mask and a final second noise mask. The first MD image is then processed with the final second noise mask to generate a final first MD image and the second MD image is processed with the final first noise mask to generate a final second MD image. | 05-31-2012 |
20120163530 | ANODE TARGET FOR AN X-RAY TUBE AND METHOD FOR CONTROLLING THE X-RAY TUBE - Anode targets for an x-ray tube and methods for controlling x-ray tubes for x-ray systems are provided. One x-ray system includes a field-generator configured to generate a field, an electron beam generator configured to generate an electron beam directed towards a target and a voltage controller configured to control the electron beam generator to produce an electron beam at a first energy level and an electron beam at a second energy level. The x-ray system also includes a field-generator controller configured to control a field to deflect at least one of the electron beams, wherein the electron beam, at the first energy level, impinges on the target at a first contact position and the electron beam, at the second energy level, impinges on the target at a second contact position. The at the first contact position and at the second contact position is configured to filter x-rays. | 06-28-2012 |
20120163557 | METHODS AND PHANTOMS FOR CALIBRATING AN IMAGING SYSTEM - A method for calibrating a medical imaging system includes performing an initial calibration of the imaging system, at a manufacturing site fabricating the imaging system, using a plurality of phantoms, shipping one of the phantoms to an installation site installing the imaging system, and performing a final calibration, at an installation site of the imaging system, using the shipped phantom. A set of calibration phantoms is also described herein. | 06-28-2012 |
20120236984 | SYSTEM AND METHOD OF ACQUIRING MULTI-ENERGY CT IMAGING DATA - A CT system includes a rotatable gantry having an opening for receiving an object to be scanned, and a controller. The controller is configured to apply a first kVp for a first time period, apply a second kVp for a second time period, integrate two or more view datasets during the first time period, integrate one or more view datasets during the second time period, and generate an image using the datasets integrated during the first time period and during the second time period. | 09-20-2012 |
20130004050 | METHOD AND SYSTEM FOR SCATTER CORRECTION IN X-RAY IMAGING - Approaches for deriving scatter information using inverse tracking of scattered X-rays is disclosed. In certain embodiments scattered rays are tracked from respective locations on a detector to a source of the X-ray radiation, as opposed to tracking schemes that proceed from the source to the detector. In one such approach, the inverse tracking is implemented using a density integrated volume that reduces the integration steps performed. | 01-03-2013 |
20130058450 | METHOD AND APPARATUS FOR ADAPTIVE SCATTER CORRECTION - A CT system includes a rotatable gantry having an opening to receive an object to be scanned, an x-ray source configured to project an x-ray beam toward the object having a primary intensity, a detector configured to detect high frequency electromagnetic energy passing through the object and output imaging data, and a data acquisition system (DAS) connected to the detector and configured to receive the imaging data. The system also includes a computer programmed to obtain image projection data of the object from the DAS, correct the projection data using a scatter function that is based at least on a known characteristic of the x-ray beam, and generate images using the corrected projection data. | 03-07-2013 |
20130058451 | METHOD OF DOSE REDUCTION FOR CT IMAGING AND APPARATUS FOR IMPLEMENTING SAME - A CT system includes an x-ray source configured to project an x-ray beam toward an object, a detector array, and a bowtie filter. The bowtie filter includes a first x-ray filtration region positioned to attenuate x-rays that pass through an isochannel of the detector array, a second x-ray filtration region positioned to attenuate x-rays that pass through channels of the detector array that are offcenter in a channel direction from the isochannel, and an x-ray attenuation material positionable to attenuate the x-rays that pass through the channels of the detector array that are offcenter in the channel direction from the isochannel. The CT system also includes a data acquisition system (DAS) connected to the detector array and configured to receive outputs from the detector array, and a computer programmed to acquire projections of imaging data of the object, and generate an image of the object using the imaging data. | 03-07-2013 |
20140133719 | SYSTEM AND METHOD FOR MULTI-MATERIAL CORRECTION OF IMAGE DATA - A method is provided. The method includes acquiring projection data of an object from a plurality of pixels, reconstructing the acquired projection data from the plurality of pixels into a reconstructed image, performing material characterization and decomposition of an image volume of the reconstructed image to reduce a number of materials analyzed in the image volume to two basis materials. The method also includes generating a re-mapped image volume for at least one basis material of the two basis materials, and performing forward projection on at least the re-mapped image volume for the at least one basis material to produce a material-based projection. The method further includes generating multi-material corrected projections based on the material-based projection and a total projection attenuated by the object, which represents both of the two basis materials, wherein the multi-material corrected projections include linearized projections. | 05-15-2014 |
20140328448 | SYSTEM AND METHOD FOR MULTI-MATERIAL CORRECTION OF IMAGE DATA - A method is provided. The method includes acquiring projection data of an object from a plurality of pixels, reconstructing the acquired projection data from the plurality of pixels into a reconstructed image, performing material characterization and decomposition of an image volume of the reconstructed image to reduce a number of materials analyzed in the image volume to two basis materials. The method also includes generating a re-mapped image volume for at least one basis material of the two basis materials, and performing forward projection on at least the re-mapped image volume for the at least one basis material to produce a material-based projection. The method further includes generating multi-material corrected projections based on the material-based projection and a total projection attenuated by the object, which represents both of the two basis materials, wherein the multi-material corrected projections include linearized projections. | 11-06-2014 |