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: A mechanism for generating an artefact estimation image that represents the effect of cone-beam artefacts in a computed tomography (CT) image. This is achieved by identifying the position of gradients (being sudden changes of intensity) in an axis of the CT image parallel to a rotation axis of the CT system that generated the CT image, where each gradient represents a source of a cone-beam artefact. A look-up table is used to individually identify the effect of a cone-beam artefact on areas surrounding each identified position of the gradient, to generate an artefact estimation image.

Abstract: A method for material decomposition of an object based on spectral X-ray scan data for the object and based on application of a frequency split approach. The method comprises using two AI models in parallel to perform the material decomposition analysis based on input spectral X-ray data, wherein the models are configured such that one exhibits higher bias and lower variance (lower noise) than the other. The input spectral X-ray data is fed to both models. The output material composition data from the low bias model is low-pass filtered and the output material composition data from the low variance model is high pass filtered. The outputs from the two models are linearly combined, either before the filtering or after. The resulting combined material decomposition data has both lower bias and lower noise compared to the output generated if just one AI model were to be used.

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: An image processing system (IPS) and related method for supporting tomographic imaging. The system comprises an input interface (IN) for receiving, for a given projection direction (pi), a plurality of input projection images at different phase steps acquired by a tomographic X-ray imaging apparatus configured for dark-field and/or phase-contrast imaging. A machine learning component (MLC) processes the said plurality into output projection imagery that includes a dark-field projection image and/or a phase contrast projection image for the said given projection direction.

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 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: The present invention relates to a system (10) for X-ray dark field, phase contrast and attenuation tomosynthesis image acquisition. The system comprises an X-ray source (20), an interferometer arrangement (30), an X-ray detector (40), a control unit (50), and an output unit. A first axis is defined extending from a centre of the X-ray source to a centre of the X-ray detector. An examination region is located between the X-ray source and the X-ray. The first axis extends through the examination region, and the examination region is configured to enable location of an objection to be examined. The interferometer arrangement is located between the X-ray source and the X-ray detector. The interferometer arrangement comprises a first grating (32) and a second grating (34). A second axis is defined that is perpendicular to a plane that is defined with respect to a centre of the first grating and/or a centre of the second grating.

Abstract: In a method and system for reconstructing computed tomography image data in which CT image data is de-noised. Then simulated noise is added, followed by another de-noising step to estimate the bias. Then, the estimated bias information is used to correct the original de-noised image data to arrive at second pass image data.

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: Present multi-spectral CT approaches are able to cancel the noise from the combined (mono-energy) image. However, medical professionals also find it useful to consult the basis images which are combined (summed) form the mono image, because they can provide useful extra diagnostic information. However, denoising of the basis images can lead to a “jagged” appearance of edges in the denoised basis images, inconveniently requiring further image processing steps to take place before the basis images can be clearly read. Accordingly, there is provided an apparatus (30) for simultaneous edge noise reduction. The apparatus comprises a processor (32). The processor is configured to receive first (s0) and second (p0) input image data, and to receive first (s) and second (p) denoised input image data. The first and second input image data contains noise which is anti-correlated between the first and the second input image data.

Abstract: In a method and system for reconstructing computed tomography image data in which CT image data is de-noised. Then simulated noise is added, followed by another de-noising step to estimate the bias. Then, the estimated bias information is used to correct the original de-noised image data to arrive at second pass image data.

Abstract: A system (300) includes input/output configured to receive line integrals from a contrast enhanced spectral scan by an imaging system. The system further includes (300) a processor (326) configured to: decompose (334) the line integrals into at least Compton scatter and a photo-electric effect line integrals; reconstruct the Compton scatter and a photo-electric effect line integrals to generate spectral image data, including at least Compton scatter and photo-electric effect images; de-noise (332) the Compton scatter and photo-electric effect images; identify (402) residual iodine voxels in the de-noised Compton scatter and the photo-electric effect images corresponding to residual iodine artifact; and produce a virtual non-contrast image using the identified residual iodine voxels.

Abstract: An imaging system (400) includes a radiation source (408) configured to emit X-ray radiation, a detector array (410) configured to detected X-ray radiation and generate projection data indicative thereof, and a first processing chain (418) configured to reconstruct the projection data and generate a noise only image. A method includes receiving projection data produced by an imaging system and processing the projection data with a first processing chain configured to reconstruct the projection data and generate a noise only image. A processor is configured to: scan an object or subject with an x-ray imaging system and generating projection data, process the projection data with a first processing chain configured to reconstruct the projection data and generate a noise only image, process the projection data with a second processing chain configured to reconstruct the projection data and generate a structure image, and de-noise the structure image based on the noise only image.

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 system and related method for signal processing. Interferometric projection data reconstructed into one or more images for a spatial distribution of a physical property of an imaged object. The interferometric projection data is derived from signals acquired by an X-ray detector (D), said signals caused by X-ray radiation after interaction of said X-ray radiation with an interferometer and with the object (OB) to be imaged, said interferometer (IF) having a reference phase. A reconstructor (RECON) reconstructs for the image(s) by fitting said data to a signal model by adapting fitting variables, said fitting variables including i) one or more imaging variables for the one or more images and ii), in addition to said one or more imaging variables, a dedicated phase variable for a fluctuation of said reference phase.

Abstract: The present invention relates to a device (100) for denoising a vector-valued image, the device (100) comprising: a generator (10), which is configured to generate an initial loss function (L_I) comprising at least one initial covariance matrix (ICM) defining a model of correlated noise for each pixel of the vector-valued image; a processor (20), which is configured to provide a final loss function (L_F) comprising a set of at least one final covariance matrix (FCM) based on the initial loss function by modifying at least one submatrix and/or at least one matrix element of the initial covariance matrix (ICM); and a noise-suppressor (30), which is configured to denoise the vector-valued image using the final loss function (L_F) comprising the set of the at least one final covariance matrix (FCM).

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 beam hardening correction method, a related calibration method for tomographic image data and a related apparatus. The tomographic image data includes attenuation data (f) and phase gradient data (g) and/or small angle scattering data (h). A correction value is computed from the attenuation data (f) by applying a function (q) to the attenuation data (f). The correction value is combined (S445) with the phase gradient data (g) or with the small angle scattering data (h).

Abstract: The present invention relates to a device for reconstructing an X-ray tomography image, the device comprising a reconstruction module, which is configured to utilize an ordered subset maximum likelihood optimization with a diagonal paraboloid approximation of a cost function for the reconstructing of the X-ray tomography image; and a calculation module, which is configured to calculate a pre-computable denominator term for the cost function for a plurality of subsets of projection data based on a distribution of diagonal denominator terms over the plurality of the subsets of the projection data.