Abstract: The present invention relates to an imaging system for imaging a region of interest comprising an illumination unit and a detection unit. The imaging system further comprises a grouping unit for grouping the detection values, wherein each group comprises at least one alpha detection value and at least one beta detection value (103). At least one alpha aperture weighting value for the at least one alpha detection value of a group is determined by using at least one position of at least one ray within the aperture (104). Furthermore, at least one beta aperture weighting value for the at least one beta detection value of a group is approximately determined using the at least one alpha aperture weighting value of the group (105). The detection values are than aperture weighted using aperture weighting values (106). The region of interest is reconstructed by backprojecting the weighted detection values (107).

Abstract: The present invention relates to an X-ray examination device and a corresponding method. A fast and periodical modulation of the X-ray flux within each detection interval is performed having a low X-ray flux at the beginning of the detection interval to ensure that no detection channel is overloaded. With increasing the X-ray flux particularly the peripheral detection channels will nm into saturation, which is detected. A saturated detector channel is stopped from further detecting radiation, and the time of effective radiation detection without saturation is measured for correcting those detection signals. From all detection signals, after any correction of detection signals from saturated detection channels, an X-ray image can be reconstructed.

Abstract: A computed tomography apparatus (10) includes spaced radiation sources (82, 84), such as anodes, which each propagate a cone-beam of radiation (40, 50) into an examination region (14). A detector (22) detects radiation which has passed through the examination region. An attenuation system (55) interposed between the radiation sources and the examination region for cone-angle dependent filtering of the cone beams. The attenuation system allows rays which contribute little to a reconstructed image to be attenuated more than rays which contribute more.

Abstract: The invention relates to an imaging system and a method for generating high-quality X-ray projections (24) of a patient (1). The system comprises a rotational X-ray device (10), for example a cone-beam CT-gantry (12), and an associated data processing unit (20). During a medical intervention, low-dose raw projections (22) of the patient (1) are continuously generated from different directions. A volume of interest (23) is then reconstructed from said projections (22), from which high-quality virtual projections (24) can be calculated for a display on a monitor (25). The number and direction of said virtual projections (24) can be arbitrarily chosen by the user.

Abstract: Since the soft tissue levels in an image usually comprise a variety of values between air and bone boundaries, it may not be obvious a priori what threshold value applies. According to an exemplary embodiment of the present invention, an examination apparatus is provided which is adapted for determining the optimal weight for subtraction of a soft tissue correction image without performing a multitude of forward and backward projections. This may be provided determining a roughness function based on a plurality of subtractions of the soft tissue streak image, each subtraction corresponding to a different weighting of the streak image.

Abstract: A method includes decomposing, with a decomposer (118), agent-based time series projection data for an object or a subject into at least an agent based component. A projection data decomposer (118) includes a time series decomposer (204) that determines agent-based projection data based on agent-based time series projection data based on at least two energy dependent components. A computer readable storage medium containing instructions which, when executed by a computer, cause the computer to perform the act of: determining an agent-based component of agent-based time series projection data utilizing at least two components of the agent-based time series projection.

Abstract: A detector array (110) of an imaging system (100) includes a radiation sensitive detector (114, 116) that detects radiation and generates a signal indicative thereof. A current-to-frequency (I/F) converter (202) converts the signal to a pulse train having a frequency indicative of the signal for an integration period. Circuitry (120) generates a first moment and at least one higher order moment based on the pulse train.

Abstract: A tomographic apparatus (10) includes at least two x-ray sources (16) that are concurrently driven with different switching patterns to generate uniquely encoded radiation. The tomographic apparatus (10) further includes at least two detectors (20) that each detect primary radiation emitted by its corresponding one of the at least two x-ray sources (16) and cross scatter radiation from at least one of the other at least two x-ray sources (16). Each of the at least two detectors (20) produces an aggregate signal representative of the detected primary and cross scatter radiation. The tomographic apparatus (10) further includes a decoupler (30) which, based on the different switching patterns, identifies at least one signal corresponding to at least one of the at least two x-ray sources (16) within the aggregate signal and associates the identified signal with its corresponding x-ray source (16).

Abstract: It is described a filter (300) for at least partially compensating for an X-ray tube (10) the target angle heel effect and preserving the tungsten spectrum of the X-rays. The filter (300) has an anode side (302) and a cathode side (304), wherein the cathode side (304) has a higher attenuation coefficient than the anode side (302). The attenuation coefficient is determined to at least partially compensate for the target angle heel effect. The filter (300) is from the same material as an anode plate (110) or the anode (108) of the X-raysource (10) which is usually tungsten or a tungsten alloy.

Abstract: Photon counting detectors may suffer from pulse sharing effects and fluorescence photon generation, which may lead to a degradation of the measured signals. According to an exemplary embodiment of the present invention, a detector unit is provided which is adapted for performing a coincidence detection and correction by comparing detection events of neighbouring cells, thereby providing for a coincidence identification followed by an individual coincidence correction. In order to reduce the number of coincidence detection and corresponding units per detector unit, a specific detector cell geometry may be applied.

Abstract: A computed tomography system includes an x-ray source (108) that rotates about and emits radiation through an imaging region (116). At least one finite energy resolution detector (112) detects the emitted radiation. The at least one finite resolution detector (112) includes a plurality of sub-detectors (204). Each of the plurality of sub-detectors (204) is associated with one or more different energy thresholds. Each of the energy thresholds is used to count a number of incident photons based on a corresponding energy level. A reconstruction system (136) reconstructs the photon counts to generate one or more images of a subject residing within the imaging region (116).

Abstract: The invention relates to a device and a method for the iterative reconstruction of the attenuation coefficients ?j in a tomographic image of an object (1) from projection measurements mi. In the update equation for ?jn during the n-th iteration the backprojected error (mi?mi?(?jn)) is weighted by a voxel dependent factor Formula (I). Such a voxel dependent update may particularly be included in the algorithms of ART or ML.

Abstract: An imaging system includes at least one radiation generating component (210) that alternately emits different radiation that traverse an examination region and a common detector (214) that detects radiation that traverses the examination region and generates a signal indicative thereof. Pulse generating circuitry (304) generates a pulse train, including a plurality of pulses, with a frequency indicative of the signal for the at least one radiation generating component (210) for a sampling interval. Processing electronics (220) determine an approximation of the signal for one of the at least one radiation generating components (210) for the sampling interval based on a number of pulses in the pulse train for the sampling interval and charge of the pulses in the pulse train.

Abstract: A system includes an image estimator (128) that generates estimated native image data from data acquired when a K-edge material is present in a scanned region during data acquisition, wherein the estimated native image data is indicative of native image data generated from data acquired when the K-edge material is not present in the scanned region during the data acquisition.

Abstract: The present application relates to a combined anti-scatter grid, cathode, and carrier for a photon detector used in spectral CT imaging. The photon detector of the present application may include a cathode having at least one outwardly extending plate and at least one base plate, a substrate having at least one anode, and a converter material, such as for example, Cadmium Zinc Telluride (“CZT”) or Cadmium Telluride. The at least one outwardly extending plate of the cathode may extend above the other detector components to act as an anti-scatter grid for the detector. Further, the at least one outwardly extending plate of the cathode may extend below the other detector components and be fixed to the at least one base plate of the detector. The converter material may be attached to at least one side of the at least one outwardly extending plate of the cathode.

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: 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: 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: A method includes concurrently modulating administration of at least two different contrast agents to a subject during an imaging procedure based on a modulation profile. The at least two different contrast agents exhibit different spectral characteristics. The method further includes performing a spectral decomposition of data indicative of the at least two different contrast agents, determining concentrations of the at least two different contrast agents based on the spectral reconstruction, and determining a perfusion parameter based on a ratio of the concentrations and the modulation profile.

Abstract: In the CT imaging of non-homogeneously moving objects such as the heart or the coronary vessel tree, there is a problem that different parts of the objects are at rest at different points in time. Thus, a gated reconstruction with a globally selected time point does not yield a sharp image of such objects. According to the present invention, a motion of the object is estimated, describing the motion of selected regions of these objects. Then, on the basis of the estimated motion, time points are determined, where these areas have minimal motion. Then, an image is reconstructed, wherein the data from which the respective regions are reconstructed, correspond to the respective time points, where the regions have minimal motion. Due to this, an improved image quality may be provided.