Abstract: The present invention relates to a method (1), resp. a device, system and computer-program product, for material decomposition of spectral imaging projection data. The method comprises receiving (2) projection data acquired by a spectral imaging system and reducing (3) noise in the projection data by combining corresponding spectral values for different projection rays to obtain noise-reduced projection data. The method comprises applying (6) a first projection-domain material decomposition algorithm to the noise-reduced projection data to obtain a first set of material path length estimates, and applying (7) a second projection-domain material decomposition algorithm to the projection data to obtain a second set of material path length estimates. The second projection-domain material decomposition algorithm comprises an optimization that penalizes a deviation between the second set of material path length estimates being optimized and the first set of material path length estimates.

Abstract: An imaging system (202) includes an X-ray radiation source (210) configured to emit radiation that traverses an examination region. The imaging system further includes a controller (220). The controller is configured to control an X-ray tube peak voltage of the X-ray radiation source to switch between at least two different X-ray tube peak voltages during a kVp switched spectral scan. The controller is further configured to control a grid voltage of the X-ray radiation source to follow the X-ray tube peak voltage during the spectral scan. The controller adjusts the grid voltage based on a predetermined mapping between a currently applied X-ray tube peak voltage and a corresponding grid voltage for a given focal spot size, thereby maintaining the given focal spot size throughout the spectral scan.

Abstract: A spectral X-ray imaging system (100) includes an X-ray source (110) and an X-ray detector (120) that are mounted to a support structure (150). The support structure (150) is configured to rotate the X-ray source (110) and the X-ray detector (120) around two or more orthogonal axes (A-A?, B-B?). One or more processors (130) are configured to cause the system (100) to perform operations that include: generating a spectral image based on the spectral image data; and identifying, in the spectral image, a position of a first fiducial marker (180i) comprising a first material, based on a first X-ray absorption k-edge energy value (190i) of the first material.

Abstract: The invention relates to a system and a method for determining a characteristic of a blood vessel portion, which comprises blood including a contrast agent exhibiting resonant absorption of x-ray photons at a specific energy. The system comprises a tunable monochromatic x-ray source (21) emitting x-ray radiation, an x-ray detector device (22) for detecting the x-ray radiation after it has travelled through the blood vessel portion. A control unit (26) varies a tuning of the x-ray source (21) to vary the energy of the x-ray radiation emitted by the x-ray source (21), and an evaluation unit (27) determines a tuning of the x-ray source (21) at which nuclear resonant absorption of the x-ray radiation incident onto the blood vessel portion occurs and estimates the characteristic on the basis of the determined tuning. The characteristic may particularly be the blood velocity in the blood vessel portion.

Abstract: A radiation detector (100) adapted for detecting leakage currents is disclosed and comprises a direct conversion material (101) for converting incident radiation, at least one first electrode (108) and a plurality of second electrodes (103) connected to surfaces of the direct conversion material (101) for collecting each generated charges upon application of an electric field, at least one current measurement device (201), and a plurality of signal processing chains (210, 220, 230). Each signal processing chain comprises a readout unit (215, 216, 217, 218, 219) for discriminating between energy values with respect to the incident radiation, and a switching element (214) for sending signals on a first signal path (2141) electrically connecting one of the plurality of second electrodes with the readout unit, or on a second signal path electrically connecting the one of the plurality of second electrodes with an input to one of the at least one current measurement devices.

Abstract: An imaging system (202) includes an X-ray radiation source (210) configured to emit radiation that traverses an examination region. The imaging system further includes a controller (220). The controller is configured to control an X-ray tube peak voltage of the X-ray radiation source to switch between at least two different X-ray tube peak voltages during a kVp switched spectral scan. The controller is further configured to control a grid voltage of the X-ray radiation source to follow the X-ray tube peak voltage during the spectral scan. The controller adjusts the grid voltage based on a predetermined mapping between a currently applied X-ray tube peak voltage and a corresponding grid voltage for a given focal spot size, thereby maintaining the given focal spot size throughout the spectral scan.

Abstract: The invention relates to an image reconstruction apparatus comprising a detector value providing unit for providing detector values for each detector element of a plurality of detector elements forming a radiation detector and for each energy bin of a plurality of predefined energy bins, a correlation value providing unit for providing correlation values, wherein a correlation value is indicative of a correlation of a detector value detected by a detector element in an energy bin with at least one of a) a detector value detected by another detector element in the energy bin, b) a detector value detected by another detector element in another energy bin, and c) a detector value detected by the detector element in another energy bin, and a spectral image reconstruction unit for reconstructing a spectral image based on the detector values and the correlation values.

Abstract: A System for image processing, comprising an input interface (IN) for receiving energy resolved count data generated by a photon-counting detector (PCD) with at least 2 energy bin but preferable more than two. A count data transformer (DT) of the system is configured to perform a transformation operation to transform the energy resolved count data into transformed count data, the operation including applying one or more weights to the count data, the weights previously obtained based on i) calibration image data for the or a photon-counting detector and ii) calibration image data for an energy integrating detector. A data convertor component (CC) is configured to convert the transformed count data into through-material path length data. The system allows emulating an energy integrating detector.

Abstract: The present invention relates to an anti-scatter grid (ASG) assembly comprising a first and a second grid, wherein the second grid is arranged on top of the first grid and comprises a lateral shift. The lamella thickness of the first grid is smaller than the lamella thickness of the second grid. The present invention further relates to a detector arrangement comprising a pixel detector and an ASG assembly arranged on top of the pixel detector.

Abstract: A radiation detector (100) adapted for detecting leakage currents is disclosed and comprises a direct conversion material (101) for converting incident radiation, at least one first electrode (108) and a plurality of second electrodes (103) connected to surfaces of the direct conversion material (101) for collecting each generated charges upon application of an electric field, at least one current measurement device (201), and a plurality of signal processing chains (210, 220, 230). Each signal processing chain comprises a readout unit (215, 216, 217, 218, 219) for discriminating between energy values with respect to the incident radiation, and a switching element (214) for sending signals on a first signal path (2141) electrically connecting one of the plurality of second electrodes with the readout unit, or on a second signal path electrically connecting the one of the plurality of second electrodes with an input to one of the at least one current measurement devices.

Abstract: The invention relates to a system and a method for determining a characteristic of a blood vessel portion, which comprises blood including a contrast agent exhibiting resonant absorption of x-ray photons at a specific energy. The system comprises a tunable monochromatic x-ray source (21) emitting x-ray radiation, an x-ray detector device (22) for detecting the x-ray radiation after it has travelled through the blood vessel portion. A control unit (26) varies a tuning of the x-ray source (21) to vary the energy of the x-ray radiation emitted by the x-ray source (21), and an evaluation unit (27) determines a tuning of the x-ray source (21) at which nuclear resonant absorption of the x-ray radiation incident onto the blood vessel portion occurs and estimates the characteristic on the basis of the determined tuning. The characteristic may particularly be the blood velocity in the blood vessel portion.

Abstract: An anti-scatter grid (ASG) for X-ray imaging with a surface (S) formed from a plurality of strips (LAM). The plurality of strips including at least two guard strips (Li,Li+1) that are thicker in a direction parallel to said surface than one or more strips (li) of said plurality of strips (LAM). The one or more strips (li) being situated in between said two guard strips (Li,Li+1).

Abstract: An X-ray detector (10) for a phase contrast imaging system (100) and a phase contrast imaging system (100) with such detector (10) are provided. The X-ray detector (10) comprises a scintillation device (12) and a photodetector (14) with a plurality of photosensitive pixels (15) optically coupled to the scintillation device (12), wherein the X-ray detector (10) comprises a primary axis (16) parallel to a surface normal vector of the scintillation device (12), and wherein the scintillation device (12) comprises a wafer substrate (18) having a plurality of grooves (20), which are spaced apart from each other. Each of the grooves (20) extends to a depth (22) along a first direction (21) from a first side (13) of the scintillation device (12) into the wafer substrate (18), wherein each of the grooves (20) is at least partially filled with a scintillation material.

Abstract: The present invention relates to a photon scanning apparatus comprising a photon source (2) to emit a photon beam (4), a photon detector (6) to detect photons emitted from the photon source (2). The photon source (2) is adapted to emit the photon beam (4) in accordance with a predetermined pulse width modulation scheme at a predetermined flux rate, wherein the pulse width modulation scheme defines pulse widths of the photon beam (4) for respective positions of the photon source (2) and the photon detector around a central axis (R) and an object to be scanned. The photon detector (6) is adapted to start detecting photons with a delay relative to the photon source starting to emit photons and to finish detecting photons prior to the photon source stopping to emit photons. The photon scanning apparatus thus only has to be calibrated for the predetermined flux rate.

Abstract: An imaging system includes a radiation source (108) configured to rotate about an examination region (106) and emit radiation that traverses the examination region. The imaging system further includes an array of radiation sensitive pixels (112) configured to detect radiation traversing the examination region and output a signal indicative of the detected radiation. The array of radiation sensitive pixels is disposed opposite the radiation source, across the examination region. The imaging system further includes a rigid flux filter device (130) disposed in the examination region between the radiation source and the radiation sensitive detector array of photon counting pixels. The rigid flux filter device is configured to filter the radiation traversing the examination region and incident thereon. The radiation leaving the rigid flux filter device has a predetermined flux.

Abstract: Present invention relates to devices and methods for determining a calcium content by analyzing cardiac spectral CT data. CT projection data (9), obtainable by scanning a cardiac region of a subject using a spectral CT scanning unit, is modelled (12) by applying a material decomposition algorithm to the projection data to provide a calcium-specific component. Tomographic reconstructions (13) of the projection data, to provide a first 3D image (8), and of the calcium-specific component, to provide a second 3D image (6), are performed. The first 3D image (8) is segmented (14) to provide an image mask (5) corresponding to a cardiovascular structure of interest, a part of the second 3D image (6) is selected (15) based on the image mask (5), and a calcium content is calculated (16) in the cardiovascular structure of interest based on the selected part of the second 3D image (6).

Abstract: The invention relates to an image reconstruction apparatus comprising a detector value providing unit for providing detector values for each detector element of a plurality of detector elements forming a radiation detector and for each energy bin of a plurality of predefined energy bins, a correlation value providing unit for providing correlation values, wherein a correlation value is indicative of a correlation of a detector value detected by a detector element in an energy bin with at least one of a) a detector value detected by another detector element in the energy bin, b) a detector value detected by another detector element in another energy bin, and c) a detector value detected by the detector element in another energy bin, and a spectral image reconstruction unit for reconstructing a spectral image based on the detector values and the correlation values.

Abstract: A method of an image processing apparatus for identifying a type of adipose body tissue within a subject, based on performing a spectral computed tomography (CT) scan of a region of interest of the subject; and using a combination of different image processing techniques to differentiate between at least two adipose tissue types within the region of interest.

Abstract: The present invention relates to a photon scanning apparatus comprising a photon source (2) to emit a photon beam (4), a photon detector (6) to detect photons emitted from the photon source (2). The photon source (2) is adapted to emit the photon beam (4) in accordance with a predetermined pulse width modulation scheme at a predetermined flux rate, wherein the pulse width modulation scheme defines pulse widths of the photon beam (4) for respective positions of the photon source (2) and the photon detector around a central axis (R) and an object to be scanned. The photon detector (6) is adapted to start detecting photons with a delay relative to the photon source starting to emit photons and to finish detecting photons prior to the photon source stopping to emit photons. The photon scanning apparatus thus only has to be calibrated for the predetermined flux rate.

Abstract: The present invention is directed towards spectral imaging, wherein a dedicated spectral imaging phantom is scanned with a spectral x-ray device to obtain spectral imaging data of the spectral imaging phantom. Said imaging data of the spectral imaging phantom is used as input for obtaining improved further imaging data of a subject of which a spectral scan is performed subsequent to or simultaneous with the spectral scan of the spectral imaging phantom. Improved further imaging data may be obtained by using the spectral phantom imaging data as input for imaging data correction, for providing a recommendation and/or for further data processing.