Abstract: The present invention relates to a system (100) and a method for correcting a number of counts (115) in an energy bin of X-ray photons detected by a photon counting detector (111) for a spectral computed tomography system (300). An illumination history (125) of the photon counting detector is taken into account to determine a gain and/or an offset of the photon counting detector. The number of counts in an energy bin of detected photons is corrected according to a correction value (135) corresponding to the determined gain and/or offset.

Abstract: Data in X-ray images of a medical device is processed in order to reduce vibration artifacts in differential phase contrast imaging. A proportionality factor between an object induced phase shift for a first x-ray energy bin and an object induced phase shift for a second x-ray energy bin is provided. At least one of a dark field signal and an object induced phase shift is determined from a detected intensity value of a pixel for the first energy bin and a detected intensity value of the pixel for the second energy bin using the proportionality factor.

Abstract: The present invention relates to a photon counting detector comprising a first direct conversion layer (10) comprising a low-absorption direct conversion material (11) for converting impinging high-energy electromagnetic radiation (100) into a first count signal and first electrical contacts (12), a second direct conversion layer (20) comprising a high-absorption direct conversion material (21) for converting impinging high-energy electromagnetic radiation (100) into a second count signal and second electrical contacts (22), said high-absorption direct conversion material having a higher absorption than said low-absorption direct conversion material, and a carrier layer (30, 30a, 30b) comprising first and second terminals (31, 32) in contact with the first and second electrical contacts and processing circuitry (35) configured to correct, based on the first count signal, the second count signal for errors, wherein said first direct conversion layer and the second direct conversion layer are arranged such that

Abstract: Phase stepping for differential phase contrast and/or dark field x-ray imaging using a switchable grating in which particles in a reservoir are aligned into wall-like x-ray absorbing structures by inducing a standing wave in a medium in the reservoir. The standing wave is modified by a second ultrasound generator that modifies the standing wave such that the pressure nodes of the first standing wave shift position.

Abstract: A switchable grating for phase contrast imaging comprising a reservoir with a medium and x-ray absorbing particles acoustically connected to a first ultrasound generator and a second ultrasound generator arranged along a side of the reservoir orthogonal to the first side. The ultrasound generators are each, individually or together, configured to generate a soundwave with a frequency and phase such that a standing wave is formed within the medium causing the x-ray absorbing particles to organize along pressure nodes of the standing waves.

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: An exemplary mounting structure can be provided for interferometric imaging and an interferometric imaging apparatus comprising same. The mounting structure comprises at least one curved surface for receiving an interferometric grating to rest thereon. The surface can be provided having a plurality of apertures, whereas that the grating when so received, covers at least one of the apertures.

Abstract: A signal processing system (SPS) and related method. The system comprises an input interface (IN) for receiving at least two data sets, comprising a first data set and second data set. The first data set is generated by an X-ray detector sub-system (XDS) at a first pixel size and the second data set generated at a second pixel size different from the first pixel size. An estimator (EST) is configured to compute, based on the two data sets, an estimate of a charge sharing impact.

Abstract: The invention is related to processing x-ray imaging data, specifically phase contrast x-ray imaging data, and addresses the problems associated, for example, with vibrations in grating-based differential phase contrast imaging by making use of spectral information. It was realized that one may make use of the spectral information in determining the vibration state of the Moiré pattern based on multi-energy-bin x-ray detectors, the energy independence of vibration-induced Moiré pattern phase shifts, the energy dependence of object-induced Moiré pattern phase shifts and a phantom designed to allow for measuring the dependence of the object-induced phase shift as a function of the energy bin. In particular, it was found that by suitable data processing the vibration-induced shifts and the like can be disentangled from the object properties and hence vibration artifacts in the image are reduced, while there is no particular need for changing the basic physical structure of the imaging device.

Abstract: The present invention relates to a photon counting detector comprising a first direct conversion layer (10) comprising a low-absorption direct conversion material (11) for converting impinging high-energy electromagnetic radiation (100) into a first count signal and first electrical contacts (12), a second direct conversion layer (20) comprising a high-absorption direct conversion material (21) for converting impinging high-energy electromagnetic radiation (100) into a second count signal and second electrical contacts (22), said high-absorption direct conversion material having a higher absorption than said low-absorption direct conversion material, and a carrier layer (30, 30a, 30b) comprising first and second terminals (31, 32) in contact with the first and second electrical contacts and processing circuitry (35) configured to correct, based on the first count signal, the second count signal for errors, wherein said first direct conversion layer and the second direct conversion layer are arranged such that

Abstract: The invention relates to a subject support device (1) to be used in a projection data acquisition apparatus (2) for acquiring projection data of a subject (3). The subject support device comprises a support component (4) providing a support surface (5) for supporting the subject while acquiring the projection data, a diffraction grating (6) for diffracting x-rays, and a moving unit (7, 8) for moving the support component and the diffraction grating relative to each other. This relative movement can allow for a movement of the support component such that the subject is moved through x-rays (16) for determining projection data of different parts of the subject, while the diffraction grating can still be traversed by the x-rays. These projection data can be used for generating a relatively large phase-contrast and/or dark-field projection image.

Abstract: The present invention relates to a device for phase stepping in phase contrast image acquisition, the device (1) comprising: a mobile grating (10); a guiding element (11); a restoring element (12); and a locking element (13); wherein the guiding element (11) is configured to guide the mobile grating (10) between a first position (2) and a second position (3); wherein the restoring element (12) is configured to apply a force to the mobile grating (10); wherein the force is directed from the first position (2) to the second position (3); and wherein the locking element (13) is configured to releasably lock the mobile grating (10) in the first position (2). In an example, during the motion of the mobile grating (10) back to equilibrium, a decoder (11a) for the position of the mobile grating (10) along the guiding element (11) may trigger at least four measurement frames over a period of at least 2*Pi.

Abstract: The invention relates to radiation detector for registering incident photons, comprising (i) detection circuitry (202, 206, 207) configured to provide an electric output signal in response to incident photons, the output signal comprising pulses having an amplitude indicative of energies deposited in the radiation detector by the incident photons, and (ii) an energy estimating circuit (2081, . . . , 208N; 2091, . . . , 209N) configured to detect that the output signal is larger than at least one threshold corresponding to an energy value in order to determine energies of incident photons. The radiation detector further comprises a registration circuit (211) configured to detect incident photons independent of a comparison of the output signal with the at least one threshold. Moreover, the invention relates to a method for detecting photons using the radiation detector.

Abstract: A method of processing a signal measured by an energy-resolving detector after passage of radiation through a sample includes receiving a measured count rate for photonic interactions with the detector, fitting a signal model to the detected counts, wherein the signal model is configured to account for a pulse-pile-up effect, the signal model representing a conditional expectation of a frequency of at least uni-directional pulse crossing of at least one energy level, given a physical quantity of a material in the sample, wherein the signal model is expressed in terms of a Fourier representation of a pulse height variable.

Abstract: An exemplary mounting structure can be provided for interferometric imaging and an interferometric imaging apparatus comprising same. The mounting structure comprises at least one curved surface for receiving an interferometric grating to rest thereon. The surface can be provided having a plurality of apertures, whereas that the grating when so received, covers at least one of the apertures.

Abstract: The invention relates to a detection values determination system, especially for photon-counting CT scanners, comprising a detection pulse providing unit for providing detection pulses for an array of detection pixels 17, which is provided with an anti-charge-sharing grid 15 for suppressing charge sharing between different clusters 14 of the detection pixels, wherein the detection pulses are indicative of the energy of photons incident on the detection pixels. Charge-sharing-corrected detection values are determined based on the provided detection pulses, wherein for determining a charge-sharing-corrected detection value for a detection pixel of a cluster only detection pixels of the same cluster are considered. This allows for a relatively high detective quantum efficiency, wherein the technical efforts for providing the charge sharing correction can be relatively low.

Abstract: An image signal processing system (ISP) comprising an input interface (IN) for receiving photon counting projection data acquired by an X-ray imaging apparatus (IA) having a photon counting detector (D). A calibration data memory (CMEM) of the system holds calibration data. The calibration data encodes photon counting data versus path lengths curves for different energy thresholds of i) said detector (D) or ii) of a different detector. At least one of said curves is not one-to-one. A path length convertor (PLC) of the system converts an entry in said photon counting projection data into an associated path length based on said calibration data.

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: A signal processing system (SPS) and related method. The system comprises an input interface (IN) for receiving at least two data sets, comprising a first data set and second data set. The first data set is generated by an X-ray detector sub-system (XDS) at a first pixel size and the second data set generated at a second pixel size different from the first pixel size. An estimator (EST) is configured to compute, based on the two data sets, an estimate of a charge sharing impact.

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).