Abstract: Tomosynthesis data may be acquired from a radiation source that substantially continuously emits radiation while its position is varied relative to a photon counting x-ray detector. The detector detects photons comprised within the radiation and photon data indicative of the detected photons is generated. The photon data may comprise data related to a detected photon's detection time, detection location on the detector, energy level, and/or trajectory from the radiation source, for example. The photon data of various photons may be compiled into a plurality of bins and, through reconstruction and tomosynthesis techniques, produce synthesized images of various tomography planes of an object under examination. In this way, the tomosynthesis techniques rely on counting photons rather than measuring their energy to create synthesized images.

Abstract: In at least one embodiment, 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.

Abstract: A method and a computed tomography scanner are disclosed for carrying out an angiographic examination of a patient, wherein the utilized computed tomography scanner includes at least one recording system mounted on a gantry such that it can rotate about a z-axis. Projection data is acquired from at least one prescribed angular position of the gantry for at least two different energies of X-ray radiation. The projection data is subsequently combined to form a resulting projection image by evaluating the projection data corresponding to the respective angular position, in which projection image at least one substance, which should be displayed selectively, is imaged with a high image contrast compared to the respective individual projection data. This procedure extends the field of application of the computed tomography scanner to projection-based angiography examinations, which were previously restricted to C-arm systems.

Abstract: A computed tomography apparatus and a method for controlling the same are provided. The apparatus is capable of switching between a high energy mode and a low energy mode at a high speed using a filter that rotates at a high speed. The computed tomography apparatus includes an X-ray generator which generates and irradiates X-rays toward a subject, an X-ray filter which includes at least one filter member, a driver which rotates the X-ray filter such that the filter members are selectively disposed in an irradiation path of X-rays generated by the X-ray generator, a detector which detects the X-rays that are transmitted to the subject, and a host apparatus which obtains X-ray images by using detected X-rays, separates the obtained X-ray images based on filter members to which the corresponding X-rays are transmitted, and reconstructs the images by using X-ray images of the identical filter member.

Abstract: An imaging system includes a radiation source (106, T1, T2, T3) that rotates about an examination region and emits radiation that traverses the examination region. The radiation source (106, T1, T2, T3) emits radiation having an energy spectrum that is selectively alternately switched between at least two different energy spectra during an imaging procedure. The system further includes an energy-resolving detector array (116, D1, D2, D3) that detects radiation traversing the examination region. The energy-resolving detector array (116, D1, D2, D3) resolves the detected radiation over at least two different energy ranges and produces energy-resolved output signals as a function of both emission energy spectrum and energy range. The system further includes a reconstructor (126) that performs a spectral reconstruction of the energy-resolved output signals. In another embodiment, the detector array (116) includes a photon-counting detector array (116).

Abstract: An X-ray CT apparatus that can efficiently set a scanning condition in a scanning operation of a periodically moving internal organ such as a heart or the like is provided. The X-ray CT apparatus collects electrocardiographic information by using a periodic motion measuring device 6 (S1). Subsequently, an operator input a time resolution rate corresponding to time resolution expected in a target examination (S2). Subsequently, the X-ray CT apparatus calculates a scanning condition under which the input time resolution rate can be implemented (S3). Subsequently, the X-ray CT apparatus images a heart under the scanning condition calculated in S3 (S4). Subsequently, the X-ray CT apparatus reconstructs an electrocardiographic-synchronous image by using the scanning data obtained in S4 and the electrocardiographic information (S5). Subsequently, the X-ray CT apparatus displays the electrocardiographic-synchronous image reconstructed in S5 on a display device 5 (S6).

Abstract: This specification is directed towards finding, locating, and confirming threat items and substances. The inspection system is designed to detect objects that are made from, but not limited to, special nuclear materials (“SNM”) and/or high atomic number materials. The system employs a dual energy CT scanning first stage inspection system and advanced image processing techniques to analyze images of an object under inspection (“OUI”), which includes, but is not limited to baggage, parcels, vehicles and cargo.

Abstract: Methods and systems are provided for protecting a critical structure during the administration of radiation treatment to a patient. A register receives proposed positions for one or more radiation beams with respect to a critical structure. A processor predicts a cumulative dose volume for the critical structure based on the dose distribution, and determines if the cumulative dose volume exceeds a tolerance value. If the cumulative dose volume exceeds the tolerance value, the dose distribution may be translated at least in part based on a relationship between the cumulative dose volume and the dose distribution position.

Abstract: An imaging system includes an x-ray source, a detector that receives x-rays emitted from the x-ray source, a DAS configured to count photon hits in the detector that occur at photon energies above at least a low keV threshold, a medium keV threshold, and a high keV threshold, and a computer operably coupled to the DAS. The computer is programmed to vary each of the medium keV threshold and the high keV threshold over a continuous keV range during data acquisition to define low, medium, and high keV bins that are based on the low, medium, and high keV thresholds, obtain photon counts in the low, medium, and high keV bins in a plurality of keV threshold combinations, calculate a noise variance as a function of at least one of the keV thresholds, and identify a noise minimum and low, medium, and high keV thresholds that correspond thereto.

Abstract: 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.

Abstract: A first generating unit generates a plurality of blood vessel image data sets at the plurality of imaging angles by performing subtraction processing for the plurality of mask image data sets and the plurality of contrast image data sets. A second generating unit generates a blood vessel volume data set including an artery region, a vein region, and a capillary vessel region by performing reconstruction processing for the plurality of blood vessel image data sets. A third generating unit generates a capillary vessel volume data set associated with the capillary vessel region by removing the artery region and the vein region from the blood vessel volume data set. A fourth generating unit generates a capillary vessel image data set by performing three-dimensional image processing for the capillary vessel volume data set.

Abstract: An x-ray CT system and a method are disclosed for creating tomographic recordings with the aid of an x-ray CT system, with two emitter/detector arrangements operating with an angular offset on a gantry with at least two different x-ray energy spectra. In at least one embodiment, at least one first recording is reconstructed from detector data from two quarter rotations with different x-ray energy spectra and at least one second recording is created from detector data of a scan of at least one of the emitter/detector arrangements over a half rotation. According to at least one embodiment of the invention, the recordings are subjected to high-pass filtering or low-pass filtering in respect of their spatial frequencies and then the filtered recordings are combined to give a resulting recording.

Abstract: An X-ray CT system of an embodiment includes the following. An imaging region data acquisition part is configured to acquire a first imaging region and a second imaging region that have different widths from each other in the body axial direction based on a scanogram as imaging regions for performing scan imaging. An irradiation field control part is configured to obtain irradiation fields for the first and the second imaging regions, and control an irradiation field regulating part corresponding to the relative positions by a moving part so as to realize the irradiation fields obtained for each the imaging region. An X-ray control part is configured to control an X-ray generating part corresponding to the relative positions by the moving part so as to irradiate X-rays to the first and the second imaging regions for the scan imaging.

Abstract: A radiation detector (24) includes a two-dimensional array of upper scintillators (30?) which is disposed facing an x-ray source (14) to convert lower energy radiation events into visible light and transmit higher energy radiation. A two-dimensional array of lower scintillators (30B) is disposed adjacent the upper scintillators (30?) distally from the x-ray source (14) to convert the transmitted higher energy radiation into visible light. Upper and lower photodetectors (38?, 30B) are optically coupled to the respective upper and lower scintillators (30?,30B) at an inner side (60) of the scintillators (30?,30B). An optical element (100) is optically coupled with the upper scintillators (30?) to collect and channel the light from the upper scintillators (30?) into corresponding upper photodetectors (38?).

Abstract: A method for estimating effective atomic number and bulk density of objects, such as rock samples or well cores, using X-ray computed tomographic imaging techniques is provided. The method effectively compensates for errors in the interpretation of CT scan data and produces bulk densities which have lower residual error compared to actual bulk densities and produces bulk density—effective atomic number trends which are consistent with physical observations.

Abstract: A CT system includes a generator configured to energize an x-ray source to a first kilovoltage (kVp) and to a second kVp, and a computer that is programmed to acquire a first view dataset with the x-ray source energized to the first kVp and a second view dataset with the x-ray source energized to the second kVp, generate a base correction image using the first view dataset and the second view dataset, and reconstruct a pair of base material images from the first view dataset and from the second view dataset. The computer is also programmed to estimate artifact correlation in the pair of base material images using the base correction image, generate a pair of final base material images and a final monochromatic image, and correct one of the pair of final base material images and the final monochromatic image at a keV value using the estimated artifact correlation.

Abstract: At least one example embodiment relates to a method and/or a device for automatically differentiating types of kidney stones using computed tomography. The method provides two image data records of two computed tomography pictures of an object area including the kidney stones that have been recorded in the context of a different spectral distribution of the X-radiation. For each voxel of a slice of the object area that has X-ray attenuation values typical of kidney stones there is calculated from the two image data records a ratio r that is yielded from X-ray attenuation values of the voxel and prescribed X-ray attenuation values of pure urine in the context of the different spectral distributions of the X-radiation. The respective voxel is assigned to one of at least two types of kidney stones as a function of the variable r.

Abstract: A dental and orthopedic densitometry modeling system includes a controller with a microprocessor and a memory device connected to the microprocessor. An input device is also connected to the microprocessor for inputting diagnostic procedure parameters and patient information. X-ray equipment including an X-ray source and an X-ray detector array are connected to a positioning motor for movement relative to a patient's dental or orthopedic structure in response to signals from the microprocessor. The output consists of a tomographical densitometry model. A dental/orthopedic densitometry modeling method involves moving the X-ray equipment across a predetermined scan path, emitting dual-energy X-ray beams, and outputting an image color-coded to correspond to a patient's dental or orthopedic density.

Abstract: A method is disclosed for displaying image data of a large intestine of a patient on the basis of tomographic examination data. In at least one embodiment, the method includes scanning of the patient, after ingestion of a contrast agent, in at least two differently aligned positions using a tomography system and generating a tomographic image data record for each position; segmenting the large intestine in the tomographic data records; detecting and marking regions of the segmented large intestine with adjacent remaining stool in the intestine (covered regions); registering the segmented large intestine in the at least two tomographic image data records; displaying a tomographic display of the segmented large intestine including markings of the covered regions; and displaying a selection menu in which tomographic displays of the segmented large intestine in the at least two differently aligned positions of the patient, including a marking of the covered regions, can be selected alternatively.

Abstract: The subject matter disclosed herein relates to X-ray imaging systems, and more specifically, to multi-energy computed tomography (CT) X-ray imaging systems. In an embodiment, a multi-energy computed tomography (CT) imaging system includes an X-ray source that emits X-rays upon the application of a low stable bias, a high stable bias, and transitional biases between the low stable bias and the high stable bias. The imaging system also includes an X-ray detector configured to produce an electrical signal corresponding to the intensity of the X-rays emitted by the X-ray source that reach the X-ray detector. The imaging system also includes data processing circuitry configured to acquire a first set of data corresponding to the electrical signal produced by the X-ray detector only when the low stable bias or the high stable bias is applied to the X-ray source. The imaging system also includes a processor configured to process the first set of acquired data and construct one or more multi-energy CT images.

Abstract: An apparatus for x-ray imaging of an object is provided. An x-ray source for providing alternating x-ray spectrums is placed on a first side of the object. A spectrum separation fixed filter is placed between the x-ray source and the object. An x-ray detector is placed on a second side of the object opposite the x-ray source. A controller controls the x-ray source and the x-ray detector.

Abstract: In a continuous mammography procedure, the breast of a subject is fixed in place in a retention device, and a first x-ray image is generated by irradiating the breast in the retention device. While the breast is still held in the retention device, the first x-ray image is evaluated to define a condition for generating a second x-ray image. The second x-ray image is then generated according to the defined condition, with the breast still in the same position in the retention device.

Abstract: A method and a computed tomography system are disclosed for generating tomographic image datasets of a measurement object with multiple simultaneously operable sets of detector elements. In at least one embodiment, at least one first set measures incident radiation over the entire energy spectrum of the incident radiation in an integrating manner and at least one second set measures incident radiation in at least two energy ranges in a resolving manner, wherein furthermore by way of the integrating measurements, the energy-resolving measurements relating in each case to rays traversing a measurement object in a spatially identical manner are corrected and a tomographic image dataset of the measurement object is reconstructed at least from the corrected energy-resolving measurements.

Abstract: 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.

Abstract: An imaging system includes an x-ray source that emits a beam of x-rays toward an object to be imaged, a detector that receives the x-rays attenuated by the object, a spectral notch filter positioned between the x-ray source and the object, a data acquisition system (DAS) operably connected to the detector, and a computer operably connected to the DAS and programmed to acquire a first image dataset at a first kVp, acquire a second image dataset at a second kVp that is greater than the first kVp, and generate an image of the object using the first image dataset and the second image dataset.

Abstract: An imaging system includes an x-ray source configured to emit a beam of x-rays toward an object to be imaged, a detector configured to receive x-rays that are attenuated by the object, a data acquisition system (DAS) operably coupled to the detector, and a computer operably coupled to the DAS and programmed to obtain scan data with two or more incident energy spectra, decompose the obtained scan data into at least three basis materials, generate an image of one of the at least three basis materials using the decomposed scan data, and replace at least one pixel in the image using decomposed data of another of the at least three basis materials.

Abstract: Disclosed is an image reconstruction method in a high-energy dual-energy CT system. The method comprises steps of scanning an objection with high-energy dual-energy rays to obtain high-energy dual-energy projection values, calculating projection values of base material coefficients corresponding to the dual-energy projection values on the basis of a pre-created lookup table or by analytically solving a set of equations, and obtaining an image of base material coefficient distribution based on the projection values of base material coefficients. The method provides a solution for reconstruction with high-energy dual energy CT technology and thus a more effective approach for substance identification and contraband inspection, thereby bringing a significant improvement on accuracy and efficiency in security inspection.

Abstract: A radiation image processing apparatus includes a radiation source for irradiating the subject with the radiation, the subject being applied with a fixation material, a radiation source controller for controlling the radiation source in accordance with different image capturing conditions, a radiation converting panel for converting the radiation into one of the pieces of radiation image information, a processing condition memory for storing a plurality of processing conditions, each including the image capturing conditions that correspond to a type of the fixation material, a processing condition selector for selecting one of the processing conditions, the selected one of the processing conditions corresponding to the type of the fixation material, and an image processor for processing in accordance with the selected processing condition the plurality of pieces of radiation image information that are provided by the radiation converting panel under the different image capturing conditions, respectively.

Abstract: An apparatus, method and computer program product for performing computer aided diagnosis on temporal subtraction images of objects. A mode of a gray-level histogram is identified, and a gray-level threshold is established at a predefined fraction of this modal value. All pixels with gray levels below this threshold that lie within the lung regions of the temporal subtraction image remain “on,” while all other pixels are set to zero. Area and circularity requirements are imposed to eliminate false-positive regions. Areas of pathologic change identified in this manner may be presented as outlines in the subtraction image or as highlighted regions in the original radiographic image so that, in effect, temporal subtraction becomes a “background” process for computer-aided diagnosis. The present invention is also directed to method, apparatus, and computer program product for performing temporal subtraction on energy subtraction images, with or without subsequent computer aided diagnosis, of objects.

Abstract: A method for determining absorption coefficients corrected with polychromy artifacts for an object composed of a plurality of material types differentiated with absorption attributes is provided. A plurality of x-ray beam projections of the object are recorded with monochrome x-rays from different positions. The recorded projections are reconstructed to determine a first set of absorption coefficients. The projections are calculated by reprojection. The recorded projections are corrected by the calculated projections. A second set of absorption coefficients corrected with polychromy artifacts is finally determined by reconstructing the corrected projections. A formula-based description of a rule taking account of polychromy is used in the calculation. The rule includes parameters to be determined by the reprojection in the course of the calculation of projections. The method combines steps of conventional methods and is thus more efficient.

Abstract: We present an iterative method for reducing artifacts in computed tomography (CT) images. First, a filter is applied to the experimental projection data that adaptively expands the detector element size in regions with low photon counts, until the desired number of photons are detected. The initial image is then calculated using an existing reconstruction technique. In each iteration, artifacts and noise in the current image are reduced by using an edge-preserving blur filter. Metal pixels (determined from the initial image) are replaced with smaller values. The resulting image is forward projected. Rays that go through metal are replaced with the forward projected values. Rays that do not pass near metal are kept at the experimental values. Filtered backprojection is then performed on the new projection data to determine the updated image. Finally, after the last iteration, metal pixels are copied from the initial image.

Abstract: A method and an image data record processing facility are disclosed for correcting image data of an examination object, which includes a first image data record obtained using a first X-ray energy and a second image data record obtained using a second X-ray energy. In this process, a corrected image data record is generated by subtracting from image point values at certain image point positions of the first image data record, image point values, which are assigned to the corresponding image point positions in the second image data record, multiplied by a weighting factor. The weighting factor here is selected as a function of the first X-ray energy used and the second X-ray energy used so that on subtraction a calcium component is removed from the image point values. A method for generating image data and an X-ray system having such an image data record processing facility are also described.

Abstract: A computed tomography system includes a radiation sensitive detector element (100) which provides outputs (DL, DH) indicative of the radiation detected in at least first and second energies or energy ranges. Energy resolving photon counters (26) further classify the detector signals according to their respective energies. Correctors (24) correct the classified signals, and a combiner (30) combines the signals according to a combination function to generate outputs (EL, EH) indicative of radiation detected in at least first and second energies or energy ranges.

Abstract: The invention relates to a method for improving the perceptibility of different structures on radiographs by means of an image processing device consisting a) in storing a radiograph in electronic form as a local space-intensity distribution, b) in carrying out a Fourier transformation for determining a frequency-intensity distribution, c) in filtering said frequency-intensity distribution by modifying weighting between the high-frequency and low-frequency image signal components, wherein the fixing of the image signal components to be more intensively weighted is carried out taking into account the mean structure size of said structures whose perceptibility is to be improved, d) in carrying out an inverse Fourier transformation of the filtered frequency-intensity distribution in order to obtain a modified space-intensity distribution in which said structures are more easily perceptible.

Abstract: The present invention relates to a medical X-ray examination apparatus and method for performing k-edge imaging of an object of interest including material showing k-edge absorption. To allow the use of conventional detector technology, which does not suffer from the limitation to provide very high k-rate capabilities a method is proposed comprising the steps of: —emitting polychromatic X-ray radiation (4; 4a, 4b), —Bragg filtering said polychromatic X-ray radiation by a Bragg filter such that radiation (16) transmitted through said Bragg filter (14; 14a, 14b) passes through said object (5), —detecting X-ray radiation after passing through said object (5), —acquiring projection data at at least two different Bragg reflection angles of said Bragg filter (14; 14a, 14b), and —reconstructing a k-edge image from the acquired projection data.

Abstract: A computed tomography scanner is disclosed for performing a spiral scan. In at least one embodiment, the computed tomography scanner includes a rotatable X-ray emitter for generating a beam fan and an X-ray detector, positioned diametrically opposite to the emitter, and an associated evaluation unit. In at least one embodiment, provision is made for an X-ray filter arranged downstream of the X-ray emitter, the position of the X-ray filter being correlated to that of the X-ray detector. Further, the X-ray filter is partly inserted into the beam fan only during operation for generating an unfiltered and, simultaneously, a filtered radiation component of the beam fan, wherein the radiation components have different X-ray spectra and wherein the evaluation unit is designed for separate evaluation of a measurement signal of the unfiltered radiation component and a measurement signal of the filtered radiation component, to obtain dual-energy images.

Abstract: An imaging system including a radiation source (110) that emits poly-chromatic radiation that traverses an examination region and a detector (116) that detects radiation traversing the examination region and produces a signal indicative of the energy of a detected photon. The system further includes an energy discriminator (122) that energy resolves the signal based on a plurality of different energy thresholds, wherein at least two of the energy thresholds have values corresponding to at least two different K-edge energies of two different elements in a mixture disposed in the examination region. The system also includes a signal decomposer (132) that decomposes the energy-resolved signal into at least a multi K-edge component representing the at least two different K-edge energies. In one instance, a stoichiometric ratio of the two different elements in the contrast agent is known and substantially constant.

Abstract: 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.

Abstract: A method of obtaining a computed tomography image of an object includes determining linear terms and non-linear beam hardening terms in a pair of line integral equations for dual-energy projection data from inserting average and difference from average attenuation terms, obtaining an initial solution of the line integral equation by setting the non-linear beam hardening terms to zero, and iteratively solving the line integral equations to obtain one line integral equations for each basis material. Attenuation by the first basis material corresponds to a photoelectric attenuation process, and attenuation by the second basis material corresponds to a Compton attenuation process. The line integral equations can be inverted by an inverse Radon procedure such as filtered backprojection to give images of each basis material. The images of each basis material can then be optionally combined to give monochromatic images, density and effective atomic number images, or photoelectric and Compton processes images.

Abstract: A dental and orthopedic densitometry modeling system includes a controller with a microprocessor and a memory device connected to the microprocessor. An input device is also connected to the microprocessor for inputting diagnostic procedure parameters and patient information. X-ray equipment including an X-ray source and an X-ray detector array are connected to a positioning motor for movement relative to a patient's dental or orthopedic structure in response to signals from the microprocessor. The output consists of a tomographical densitometry model. A dental/orthopedic densitometry modeling method involves moving the X-ray equipment across a predetermined scan path, emitting dual-energy X-ray beams, and outputting an image color-coded to correspond to a patient's dental or orthopedic density.

Abstract: Pseudo dual-energy material identification systems and methods with under-sampling are disclosed. The system comprises a ray generating device, a mechanic rotation control section, a data collecting subsystem comprising a first tier of detectors and a second tier of detectors, and a master control and data processing computer. The system utilizes a CT-imaging-based material identification method with under-sampled dual-energy projection data, in which only a few detectors at the second tier are used to perform dual-energy projection data sampling, and optimization is made on the procedure of solving an equation system.

Abstract: Provided is an X-ray CT apparatus which can perform CT scan of multi-energy scanning at a high speed and can obtain an image having an excellent substance distinguishing ability. The X-ray CT apparatus includes: means to continuously perform a first CT scanning using a first X-ray energy and a second CT scanning using a second X-ray energy without interrupting CT scan; means to transit the X-ray energy emitted from the X-ray during a transition period TR including an end of the first CT scanning and a beginning of the second CT scanning from the first X-ray energy to the second X-ray energy; and means to compensate the scan data in the transition period by the opposing data in the residual scan period so as to reconstruct an image.

Abstract: In an X-ray CT apparatus 1 and an X-ray CT method, the thickness of an object to be inspected is computed on the basis of the number of transmitted X-rays in a specific energy range set above and below the K-absorption edge of an X-ray contrast medium serving as the object to be inspected, and a CT image is reconstructed on the basis of the computed thickness of the object to be inspected. Such X-ray CT apparatus 1 and X-ray CT method can generate an X-ray CT image stably and independently of the size of the object to be inspected and of X-ray tube voltage (X-ray energy distribution).

Abstract: Fast kV-switching is a dual energy acquisition technique in computed tomography (CT) in which alternating views correspond to the low and high tube voltages. Its high temporal resolution and its suitability to a variety of source trajectories make it an attractive option for dual energy data acquisition. Its disadvantages include a one-view misregistration between the data for high and low voltages, the potentially poor spectrum separation due to the more-like a sine wave rather than the desired square wave in fast kV-switching, and the higher noise in the low voltage data because of the technical difficulty in swinging the tube current to counter the loss of x-ray production efficiency and loss of penetration at lower tube voltages.

Abstract: According to one embodiment, a medical image processing apparatus includes an image storage unit, an estimation unit, a combination ratio determination unit, and a combined image generation unit. The estimation unit is configured to estimate an abundance ratio of one of a first and second substances to the other for each pixel based on attenuation coefficients of the first substance which correspond to a first and second energies, the attenuation coefficients of a second substance which correspond to the first and second energies, and pixel values of a first and second medical images. The combination ratio determination unit is configured to determine combination ratios of pixel values between the first and second medical images for each pixel based on the abundance ratios of the first and second substances and the attenuation coefficients of the first and second substances which are associated with a target energy.

Abstract: 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.

Abstract: An imaging system includes an x-ray source, a detector that receives x-rays emitted from the x-ray source, a DAS configured to count photon hits in the detector that occur at photon energies above at least a low keV threshold, a medium keV threshold, and a high keV threshold, and a computer operably coupled to the DAS. The computer is programmed to vary each of the medium keV threshold and the high keV threshold over a continuous keV range during data acquisition to define low, medium, and high keV bins that are based on the low, medium, and high keV thresholds, obtain photon counts in the low, medium, and high keV bins in a plurality of keV threshold combinations, calculate a noise variance as a function of at least one of the keV thresholds, and identify a noise minimum and low, medium, and high keV thresholds that correspond thereto.

Abstract: It is described a method for dynamically optimizing the signal-to-noise ratio of attenuation data related to two different X-ray energies for reconstructing an image of an object under examination. The method comprises (a) estimating the thickness and the material composition of the object at a plurality of different projection angles, (b) for each of the various projection angles calculating for a variety of combinations of different first and second X-ray energies a corresponding common signal-to-noise ratio, (c) for each of the various projection angles choosing the first and the second X-ray energy causing the maximum corresponding common signal-to-noise ratio, and (d) for each of the various projection angles acquiring X-ray attenuation data of the object whereby the two X-ray energies are the X-ray energies causing a maximum signal-to-noise ratio assigned to the respective projection angle.

Abstract: An imaging system includes an x-ray source that emits a beam of x-rays toward an object to be imaged, a detector that receives the x-rays attenuated by the object, a spectral notch filter positioned between the x-ray source and the object, a data acquisition system (DAS) operably connected to the detector, and a computer operably connected to the DAS and programmed to acquire a first image dataset at a first kVp, acquire a second image dataset at a second kVp that is greater than the first kVp, and generate an image of the object using the first image dataset and the second image dataset.

Abstract: A system and method for dual energy CT spectral imaging that provides for accurate blood vessel stenosis visualization and quantification is disclosed. The CT system includes an x-ray source configured to project x-rays toward a region-of-interest of a patient that includes a blood vessel in a stenosed condition and having a plaque material therein. The CT system also includes an x-ray detector to receive x-rays emitted by the x-ray source and attenuated by the region-of-interest, a data acquisition system (DAS) operably connected to the x-ray detector, and a computer programmed to obtain a first set of CT image data for the region-of-interest at a first chromatic energy level, obtain a second set of CT image data for the region-of-interest at a second chromatic energy level that is higher than the first chromatic energy level, and identify plaque material in the region-of-interest by analyzing the second set of CT image data.