Abstract: A method and a related system (IMA) for reconstructing an image of an electron density in a subject PAT. An x-ray radiation imager is used to expose the subject PAT to radiation to receive projection data. The reconstruction method combines projection data from two channels, namely Compton scatter based attenuation data pC and phase shift data pd?.

Abstract: A phase contrast X-ray imaging system of an object includes an X-ray source, an X-ray detector arrangement, and a grating arrangement with a phase-grating structure and an analyzer-grating structure. The X-ray detector arrangement includes at least eight line-detector units parallel to each other in a first direction, the line-detector units extending linearly in a direction perpendicular to the first direction. The phase-grating structure has a number of linear phase-gratings having a first part with first phase-gratings with slits in the first direction, and a second part with second phase-gratings with slits in a second direction different than the first direction. The analyzer-grating structure has a number of linear analyzer-gratings having a first part with first analyzer-gratings with slits in the first direction, and a second part with second analyzer-gratings with slits in the second direction.

Abstract: A system and method for generating phase image data by using the same detector to simultaneously operate in two different modes to simultaneously obtain first and second x-ray image data with different spectral weightings. The first and second x-ray image data respectively include first and second pixel-wise measurement signal values. The detector is configured to obtain the first x-ray image data in a first measurement mode and obtain the second x-ray image data in a second measurement mode different from the first measurement mode for generating the phase image data. The generated phase image data includes pixel-wise phase values from the first and second x-ray image data and is determined by determining a phase value at a pixel from a first measurement signal value obtained in the first measurement mode at the pixel, and from a second measurement signal value obtained in the second measurement mode at the pixel.

Abstract: An imaging system (100) includes a radiation source (110) with a focal spot (204) that emits a beam of x-ray photons that traverses an examination region (106). The imaging system further includes a photon counting detector array (122) that detects a sub-set of the x-ray photons that traverse an examination region. The imaging system further includes a controller (116) that generates and transmits a pause signal, in response to a calculated drop in an intensity of the emitted the beam of x-ray photons below a predetermined intensity level, which causes the photon counting detector array to pause detecting the sub-set of the x-ray photons. The imaging system further includes a counter (136) that counts, for each of a plurality of counting periods, the x-ray photons of the sub-set detected by the photon counting detector array in the corresponding counting period.

Abstract: A phase contrast imaging apparatus (MA) and related image processing method. The imaging apparatus includes a movable arm (AR) that carries a detector (D) and one or more interferometric gratings (G0, G1, G2). The imaging apparatus includes a rigidizer (RGD) to control the rigidity of at least the arm (AR) or a mounting (GM) for the gratings (G0, G1, G2). This allows controlling a drift of a Moiré pattern as detected in a sequence of readouts. A phase of the so controlled Moiré pattern can be used to calibrate the imaging apparatus by using the image processing method.

Abstract: In phase-contrast imaging, different types of image information, such as absorption image information and differential phase-contrast image information, may be obtained by a single image acquisition process and have different image properties. A frequency dependent combination of different types of image information is obtained, the combined image having improved properties over the image information and respective image information types. Accordingly, an apparatus and a method for image processing in X-ray imaging of an object is provided, including receiving first and second image information of the object of first and second image information types, respectively, where the second image information type is different from the first image information type. The first and second image information is combined to obtain combined image information of the object, where the combined image information is frequency-dependent, depending on spatial frequencies of the first and second image information, respectively.

Abstract: The invention relates to a grating arrangement and a method for spectral filtering of an X-ray beam (B), the grating arrangement comprising: a dispersive element (10) comprising a prism configured to diffract the X-ray beam (B) into a first beam component (BC1) comprising a first direction (D1) and a second beam component comprising (BC2) a second direction (D2), tilted with respect to the first direction; a first grating (20) configured to generate a first diffraction pattern (DP1) of the first beam component (BC1) and a second diffraction pattern (DP2) of the second beam component (BC2), the second diffraction pattern (DP2) shifted with respect to the first diffraction patter (DP1); and a second grating (30) comprising at least one opening (31) which is aligned along a line (d) from a maximum (MA) to a minimum (MI) of intensity of the first diffraction pattern (DP1) or of the second diffraction pattern (DP2).

Abstract: An X-ray system (2) for acquiring an image of an object has an X-ray detector (8), which is segmented into a plurality of neighboring detector tiles. In particular, the image can be a two-dimensional projection image but also a three-dimensional volume of the object reconstructed from a tomosynthesis acquisition. An X-ray detector moving mechanism (18) is adapted for moving the X-ray detector (8) at least between a first X-ray detector position and a second X-ray detector position during operation of the X-ray system. An X-ray source (4), a collimator (22) and the X-ray detector (8) of the X-ray system (2) are adapted for acquiring a plurality of partial X-ray images through the adjacent detector tiles while irradiating the object with X-ray beams from a plurality of tomographic angles a. The processing unit is adapted for generating a two-dimension image of the object and/or for reconstructing a three-dimensional volume of the object from the acquired partial images.

Abstract: Detection apparatus for detecting radiation The invention relates to a detection apparatus for detecting radiation. The detection apparatus comprises at least two scintillators (14, 15) having different temporal behaviors, each generating scintillation light upon reception of radiation, wherein the generated scintillation light is commonly detected by a scintillation light detection unit (16), thereby generating a common light detection signal. A detection values determining unit determines first detection values by applying a first determination process and second detection values by applying a second determination process, which is different to the first determination process, on the detection signal. The first determination process includes frequency filtering the detection signal.

Abstract: A detector array includes at least one direct conversion detector pixel (114-114M) configured to detect photons of poly-chromatic ionizing radiation. The pixel includes a cathode layer (116), an anode layer (118) including an anode electrode (118-118 M ) for each of the at least one detector pixels, a direct conversion material (120), disposed between the cathode layer and the anode layer, and a gate electrode disposed in the direct conversion material, parallelto and between the cathode and anode layers.

Abstract: The present invention relates to differential phase-contrast imaging of an object (108). When reconstructing image information from differential phase-contrast image data, streak- like artefacts (502) may occur. The artefacts (502) may substantially reduce legibility of reconstructed image data. Accordingly, it may be beneficial for removing or at least suppressing said artefacts (502). Thus, a method (400) for regularized phase retrieval in phase-contrast imaging is provided comprising receiving (402) differential phase-contrast image data of an object (108); generating (404) reconstructed image data of an object (108) and presenting (406) reconstructed image data of the object (108). The differential phase-contrast image and the reconstructed image data comprise a two-dimensional data structure having a first dimension and a second dimension. Generating reconstructed image data comprises integration of image data in one of the first dimension and the second dimension of the data structure.

Abstract: A method and a related system (IMA) for reconstructing an image of an electron density in a subject PAT. An x-ray radiation imager is used to expose the subject PAT to radiation to receive projection data. The reconstruction method combines projection data from two channels, namely Compton scatter based attenuation data pC and phase shift data pd?.

Abstract: The present invention relates to a method and apparatus for X-ray phase contrast imaging. The method comprises the following steps: from the measured phase gradient and overall attenuation information, an electron density is computed; the contribution pC of the Compton scattering to the overall attenuation is estimated from the electron density; the contribution pp of the photo-electric absorption to the overall attenuation is estimated from the overall attenuation and the contribution pC; the values pC and pp are used to reconstruct a Compton image and a photo-electric image; by linear combination of these two images, a monochromatic image at a desired energy is obtained.

Abstract: An imaging system (500) includes a focal spot (508) that rotates along a path around an examination region and emits a radiation beam that traverses a field of view of the examination region and a subject or object therein. The system further includes a detector array (520) that is located opposite the radiation source, across the examination region. The detector array detects radiation traversing the field of view and outputs a signal indicative of the detected radiation. The system further includes a beam shaper that is located between the radiation source and the examination region. The beam shaper rotates with the focal spot and, relative to the focal spot, in an opposite direction of the focal spot with a same angular frequency as the rotating of the focal spot and attenuates the radiation beam which reduces a flux density across the detector array at each rotational angle of the focal spot.

Abstract: The present invention relates to phase-contrast imaging which visualizes the phase information of coherent radiation passing a scanned object. Focused gratings are used which reduce the creation of trapezoid profile in a projection with a particular angle to the optical axis. A laser supported method is used in combination with a dedicating etching process for creating such focused grating structures.

Abstract: The present invention relates to calibration in X-ray phase contrast imaging. In order to remove the disturbance due to individual gain factors, a calibration filter grating (10) for a slit-scanning X-ray phase contrast imaging arrangement is provided that comprises a first plurality of filter segments (11) comprising a filter material (12) and a second plurality of opening segments (13). The filter segments and the opening segments are arranged alternating as a filter pattern (15). The filter material is made from a material with structural elements (14) comprising structural parameters in the micrometer region. The filter grating is movably arranged between an X-ray source grating (54) and an analyzer grating (60) of an interferometer unit in a slit-scanning system of a phase contrast imaging arrangement. The slit-scanning system is provided with a pre-collimator (55) comprising a plurality of bars (57) and slits (59). The filter pattern is aligned with the pre-collimator pattern (61).

Abstract: A method includes determining calibration factors for calibrating photon-counting detectors of a spectral imaging system by combining a heuristic calibration of the photon-counting detectors and an analytical calibration of the photon-counting detectors and generating a set of photon-counting calibration factors based on the combining of the a heuristic calibration and the analytical calibration. The photon-counting calibration factors, when applied to measured energy-resolved data from the photon-counting detectors of a spectral CT scan of a subject or object, mitigate spectral distortion caused by a radiation intensity profile shaper that filters a radiation beam of the spectral CT scan.

Abstract: The invention relates to a method and a pulse processing circuit (100) for the processing of current pulses (CP) generated by incident photons (X) in a piece of converter material, for instance in a pixel (11) of a radiation detector. Deviations of the pulse shape from a reference are detected and used to identify pulse corruption due to pile-up effects at high count rates and/or charge sharing between neighboring pixels. The deviation detection may for instance be achieved by generating, with a pulse shaper (110), bipolar shaped pulses from the current pulse (CP) and/or two shaped pulses of different shapes which can be compared to each other.

Abstract: In X-ray differential phase-contrast imaging. In order to enhance the information acquired by phase-contrast imaging, an analyzer grating (34) is provided with an absorption structure (48). The latter includes a first plurality (50) of first areas (52) with a first X-ray attenuation, and a second plurality (54) of second areas (56) with a second X-ray attenuation. The second X-ray attenuation is smaller than the first X-ray attenuation, and the first and second areas are arranged periodically in an alternating manner. A third plurality (58) of third areas (60) is provided with a third X-ray attenuation, which lies in a range from the second X-ray attenuation to the first X-ray attenuation, wherein every second of the first or second areas is replaced by one of the third areas.

Abstract: An X-ray differential phase-contrast imaging system has three circular gratings. The circular gratings are aligned with the optical axis of the radiation beam and a phase stepping is performed along the optical axis with the focal spot, the phase grating and/or the absorber grating. The signal measured is the phase-gradient in radial direction away from the optical axis.