Abstract: Disclosed is an X-ray sensor having an active detector region including detector diodes on its surface. The X-ray sensor further includes a junction termination surrounding the surface region including the detector diodes. The junction termination includes a guard arranged closest to the end of the surface region, a field stop outside the guard and at least two field limiting rings, FLRs arranged between the guard and the field stop. A first FLR is arranged at a distance ?1 from the guard selected from the interval [4 ?m; 12 ?m], a second FLR is arranged at a distance ?2 from the first FLR selected from the interval [6.5 ?m; 14 ?m], and wherein the distance ?2 is larger than the distance ?1. The proposed technology also provides a method for constructing such an X-ray sensor and an X-ray imaging system including an X-ray detector system that includes such X-ray sensor.

Abstract: A thermal management system and method for cooling a CT detector assembly of a CT imaging system. The thermal management system uses a combination of air cooling for the readout electronics of the CT detector assembly and liquid cooling for the X-ray sensors of the CT detector assembly. The hybrid air and liquid cooling systems and methods may be coupled together in the thermal management system and method to create a cooler temperature in the CT detector assembly. The CT detector assembly components may include CT detector modules, which may include X-ray sensors, readout electronics and other components.

Abstract: There is provided a circuit (502; 503; 504) configured for operation with a multi-bin photon-counting x-ray detector (20) having multiple energy thresholds, wherein said circuit (502; 503; 504) is configured to obtain or generate several Total Time-Over-Threshold (TTOT) signals corresponding to several different energy thresholds, and provide energy integrating information based on said several TTOT signals.

Abstract: There is provided an edge-on x-ray detector configured for detecting incoming x-rays. The edge-on x-ray detector includes a plurality of adjacent x-ray sensors, and each x-ray sensor is oriented edge-on to incoming x-rays. The x-ray sensors are arranged side-by-side and/or lined up one after the other, and the interspacing between the x-ray sensors is at least partly filled with a gap filling material including a mixture or compound of resin and metal disulfide.

Abstract: There is provided a circuit (502; 503; 504) configured for operation with a multi-bin photon-counting x-ray detector (20) having multiple energy thresholds, wherein said circuit (502; 503; 504) is configured to obtain or generate several Total Time-Over-Threshold (TTOT) signals corresponding to several different energy thresholds, and provide energy integrating information based on said several TTOT signals.

Abstract: Disclosed is a calibration phantom for an x-ray imaging system having an x-ray source and an x-ray detector. The calibration phantom includes a combination of geometric objects of at least three different types and/or compositions including: a first object located in the middle, including a first material; a plurality of second objects arranged around the periphery of the first object, at least a subset of the second objects including a second material different than the first material, wherein the first object is relatively larger than the second objects; a plurality of third objects arranged around the periphery of the first object and/or around the periphery of at least a subset of the second objects, at least a subset of the third objects including a third material different than the first material and the second material, wherein the third objects are relatively smaller than the second objects.

Abstract: Disclosed is a method and corresponding system for correcting the pileup effect in energy-discriminating photon-counting detectors. According to a first aspect, there is provided a method for pileup correction in a non-paralyzable energy-discriminating photon-counting x-ray detector operating based on a number of energy bins. The method includes adding, for each of a number of energy bins, a correction term to the detected signal of the energy bin, the correction term being a product of two separable parameterized functions, each of which includes at least one parameter, where a first parameterized function depends on a weighted sum of the detected signal over the energy bins, and where a second parameterized function depends on the detected signal(s) in one or several energy bin(s). By assuming separability and ignoring any cross correlations, the number of parameters and the complexity of the pileup correction algorithm are reduced substantially.

Abstract: An x-ray imaging system includes an x-ray source and detector. The detector is a photon counting x-ray detector, enabling detection of photon-counting events. The system acquires at least one phase contrast image based on photon-counting events. The detector includes x-ray detector sub-modules, also referred to as wafers, each including detector elements. The sub-modules are oriented in edge-on geometry with their edge directed towards the x-ray source, assuming the x-rays enter through the edge. Each sub-module or wafer has a thickness with two opposite sides of different potentials to enable charge drift towards the side, where the detector elements/pixels, are arranged. The system estimates charge diffusion from a Compton interaction or an interaction through photoeffect related to an incident x-ray photon in a sub-module or wafer of the x-ray detector, and estimates a point of interaction of the x-ray photon sub-module based on the determined estimate of charge diffusion.

Abstract: An x-ray imaging apparatus includes an x-ray source and detector with multiple detector elements. The source and detector are on a support that rotates around a subject, enabling projections at different view angles. The apparatus operates the x-ray source in switched kVp mode for alternately applying different voltages, including lower and higher voltages, during rotation to enable lower-energy and higher-energy exposures over the projections, providing for lower-energy projections and higher-energy projections. The x-ray detector is a photon-counting multi-bin detector allocating photon counts to multiple energy bins, and the apparatus selects counts from at least a subset of the bins to provide corresponding photon count information for both lower- and higher-energy projections.

Abstract: There is provided an edge-on x-ray detector configured for detecting incoming x-rays. The edge-on x-ray detector includes a plurality of adjacent x-ray sensors, and each x-ray sensor is oriented edge-on to incoming x-rays. The x-ray sensors are arranged side-by-side and/or lined up one after the other, and the interspacing between the x-ray sensors is at least partly filled with a gap filling material including a mixture or compound of resin and metal disulfide.

Abstract: The disclosed method enables estimating an initial point of interaction of an x-ray photon in a photon-counting x-ray detector, based on a number of x-ray detector sub-modules or wafers, each including detector elements. The x-ray detector sub-modules are oriented in edge-on geometry with the edge directed towards the x-ray source, assuming the x-rays enter through the edge. Each detector sub-module or wafer has a thickness with two opposite sides of different potentials to enable charge drift towards the side, where the detector elements, also referred to as pixels, are arranged. Basically, the method includes: determining an estimate of charge diffusion originating from a Compton interaction or an interaction through photoeffect related to the x-ray photon in a detector sub-module or wafer of the x-ray detector; and estimating the initial point of interaction along the thickness of the detector sub-module based on the determined estimate of charge diffusion.

Abstract: There is provided an x-ray detector having a number of x-ray detector sub-modules. Each detector sub-module is an edge-on detector sub-module having an array of detector elements extending in at least two directions, wherein one of the directions has a component in the direction of incoming x-rays. The detector sub-modules are stacked one after the other and/or arranged side-by-side. For at least part of the detector sub-modules, the detector sub-modules are arranged for providing a gap between adjacent detector sub-modules, where at least part of the gap is not directed linearly towards the x-ray focal point of an x-ray source.

Abstract: An edge-on photon-counting detector includes at least one detector module having a respective edge facing incident X-rays. The at least one detector module includes a semiconductor substrate. The edge-on photon-counting detector also includes a plurality of active integrated pixels arranged in the semiconductor substrate.

Abstract: There is provided an arrangement including an x-ray detector arranged in conjunction with in-line x-ray focusing optics configured for manipulation of x-rays in medical transmission radiography, wherein the in-line x-ray optics includes an array of lenses, in which the lenses cover parts of, or the entire, field of view, and in which the x-ray detector is a photon-counting detector. Furthermore, the x-ray detector is an energy-resolving detector and chromatic aberration of the lens array and/or limited coherence of the source is compensated for by the energy resolution of the energy-resolving detector, and/or the x-ray detector is a depth-resolving detector and chromatic aberration of the lens array and/or limited coherence of the source is compensated for by depth resolution or volumetric resolution in the detector.

Abstract: There is provided a photon-counting x-ray detector system (200) comprising a plurality of photon-counting channels (220), and at least one anti-coincidence circuit (230), each of which is connected to least two of the channels and configured to detect coincident events in the connected channels. The x-ray detector system (200) further comprises an anti-coincidence controller (240) configured to control the operation of said at least one anti-coincidence circuit based on photon count information by gradually adapting the operation of said at least one anti-coincidence circuit with increasing count rates, starting from a threshold count rate.

Abstract: An X-ray sensor (1) having an active detector region including a plurality of detector diodes (2) arranged on a surface region (3) of the X-ray sensor (1), a junction termination (4) surrounding the surface area (3) including the plurality of detector diodes (2), the junction termination (4) including a guard (5) arranged closest to the end of the surface region (3), a field stop (6) arranged outside the guard (2) and a number N of field limiting rings, FLRs (7) arranged between the guard (5) and the field stop (6), wherein each of the FLRs (7) are placed at positions selected so that distances between different FLRs (7) and between the guard and the first FLR lie within an effective area, the effective area being bounded by the lines ?=(10+1.3×(n?1)) ?m and ?=(5+1.05×(n?1)) ?m.

Abstract: Disclosed is a method for management of geometric misalignment in an x-ray imaging system having an x-ray source, a photon-counting x-ray detector and an intermediate collimator structure in the x-ray path between the x-ray source and the x-ray detector. The x-ray detector includes a plurality of pixels, and the collimator structure includes a plurality of collimator cells, wherein each of at least a subset of the collimator cells corresponds to a N×M matrix of pixels, where at least one of N and M is greater than one. The method includes monitoring, for a designated subset of pixels including at least two pixels that are affected differently by shadowing from the collimator structure due to geometric misalignment, output signals from the pixels of the designated subset, and determining the occurrence of geometric misalignment based on the monitored output signals from the pixels of the designated subset of pixels.

Abstract: A photon-counting detector includes a first subset of detector modules and at least one second subset of detector modules. Each detector module has power-consuming circuitry. Power-consuming circuitry of detector modules in the first subset is configured, in an operational mode in which the detector modules are powered on, to consume a first amount of power. Correspondingly, power-consuming circuitry of detector modules in the at least one second subset is configured, in the operational mode, to consume a second amount of power that is lower than the first amount of power.

Abstract: There is provided a method and an arrangement for determining a position of interaction of a photon in an individual detector diode of a photon-counting x-ray detector. The method includes determining the position of interaction in the detector diode based on pulse characteristics of a pulse generated by the individual detector diode in response to the photon interaction.

Abstract: A method for reconstructing image data from x-ray data measured with an imaging system having at least one photon-counting detector includes obtaining a representation of data measured by the photon-counting detector. The method also includes generating first image data based on a projection based first functional using a first algorithm, the projection based first functional being dependent on the representation of data. The method also includes updating, based on a second functional that includes a model of at least one physical effect not included in the projection based first functional, the first image data to obtain second image data. The invention also provides an image processing device configured to reconstruct image data from x-ray data measured with an imaging system including at least one photon-counting detector as well as a corresponding computer program product.