Abstract: Disclosed is a photon-counting x-ray detector system having a plurality of photon-counting channels, and at least one anti-coincidence circuit, 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 further includes an anti-coincidence controller configured to control the operation of the at least one anti-coincidence circuit based on photon count information by gradually adapting the operation of the at least one anti-coincidence circuit with increasing count rates, starting from a threshold count rate.

Abstract: Disclosed is an edge-on photon counting detector and a method for manufacturing a charge collecting side of such detector. The edge-on photon counting detector comprises a semi-conducting substrate. The semi-conducting substrate comprises, a first end adapted to face an x-ray source and a second end opposite the first end in the direction of incoming x-rays, and at least one strip having N depth segments, N?2, each of the depth segments comprising a charge collecting metal electrode and a charge collecting side comprising doped regions and insulating regions, wherein each of the charge collecting metal electrodes is arranged over a corresponding doped region and is connected to a respective routing trace arranged on the insulating regions, the respective routing trace being adapted to conduct signals from the charge collecting metal electrode to a read-out pad E, connectable to front-end electronics, arranged at the second end.

Abstract: An X-ray detector system includes a photon-counting detector with multiple detector modules including a respective power-consuming circuitry. At least some of the detector modules include a temperature sensor to monitor a temperature on the detector module and generate a temperature representing signal. A detector controller selectively switches, for at least a subset of the detector modules, the detector modules between an idle mode in which at least a respective part of the detector modules is powered off and an operational mode in which the detector modules are powered on. The power-consuming circuitries of the at least a subset of detector modules generate calibration data based on the temperature representing signals to correct for any temperature-induced changes to image data generated by the photon-counting detector.

Abstract: Disclosed is a measurement method performed by a Computed Tomography, CT, system. The CT system includes an x-ray source (60) and an x-ray detector (50) array of photon counting edge-on detectors (5), wherein each photon counting edge-on detector has a number of depth-segments, also referred to as detector elements, arranged at different spatial locations in the direction of incoming x-rays (45). The method includes to apply a time offset measurement scheme that provides a time offset between measurement periods for at least two different detector elements located at different depths, wherein the time offset is chosen so that at least two measurement periods at least partially overlaps in time. Disclosed is also a corresponding CT system (10), a control unit for a CT system and a measurement circuit for a CT system. A computer program (225) controlling a CT system is also disclosed. The disclosed technology provides for a higher sampling frequency in the angular direction (55).

Abstract: There is provided a method for processing a radiographic image acquired with at least two energy levels. A first step (S1) involves providing energy-resolved image data representative of the radiographic image with at least two energy levels, e.g. from a detector or from an intermediate storage. A second step (S2) involves decomposing the provided image data into at least one basis image representation, based on a model where a combination of at least two basis functions is used to express a representation of at least one linear attenuation coefficient, and where at least one basis function models a physical material and at least one other basis function models the Non-Linear Partial Volume, NLPV, effect.

Abstract: There is provided an x-ray sensor (21) comprising an active detector region including a plurality of detector diodes (22) at a first side of the sensor, and a common junction termination (23) at a second opposite side of the sensor. Normally, this implies that the junction termination (23) is moved from the top side where the active detector area is located to the bottom side of the sensor, allowing for full utilization of the active detector area at the top side with detector diodes to the very edge of the sensor.

Abstract: There is provided a measurement circuit (30) for an x-ray detector (5). The measurement circuit (30) is configured to sample measurement data to generate data points and process the data points before read-out to produce new data points by combining two or more data points which have been acquired at different times such that the number of data points for read-out are less than the number of original data points.

Abstract: There is provided a detector module (1) for a modular x-ray detector, wherein the detector module (1) includes multiple x-ray detector substrates (10) and associated anti-scatter collimators (20). Each x-ray detector substrate (10) has a number of detector diodes, and each x-ray detector substrate has an associated anti-scatter collimator (20). Each x-ray detector substrate (10) has an integrated circuit (30) for collecting x-ray signals from the diodes attached to the x-ray detector substrate at the bottom of the x-ray detector substrate assuming the top is where the x-rays enter, and the associated anti-scatter collimator (20) is placed above the integrated circuit (30).

Abstract: Disclosed is a detector system for x-ray imaging. The detector system includes a detector having a plurality of edge-on detector modules. Each of the edge-on detector modules includes a first edge that is adapted to be oriented towards an x-ray source and a front-side running essentially parallel to the direction of incoming x-rays. The front-side includes at least one charge collecting electrode. At least a subset of the plurality of edge-on detector modules being pairwise arranged, front-side to front-side, whereby a front-side to front-side gap is defined between the front-sides of the pairwise arranged edge-on detector modules. The pairwise arranged edge-on detector modules are associated with an anti-scatter collimator arranged in the x-ray path between the x-ray source and the edge-on detector modules and overlapping the front-side to front-side gap.

Abstract: There is provided a method of image reconstruction based on energy-resolved image data from a photon-counting multi-bin detector or an intermediate storage. The method includes processing (S1) the energy-resolved image data by performing at least two separate basis decompositions using different number of basis functions for modeling linear attenuation, wherein a first basis decomposition is performed using a first smaller set of basis functions to obtain at least one first basis image representation, and wherein a second basis decomposition is performed using a second larger set of basis functions to obtain at least one second basis image representation. The method also includes reconstructing a first image based on the at least one first basis image representation obtained from the first basis decomposition, and combining the first image with information representative of the at least one second basis image representation.

Abstract: There is provided an arrangement (100) for enabling assessment of scoliosis. The arrangement (100) is configured to obtain at least one x-ray image by means of one or more photon-counting x-ray detectors. The arrangement (100) is further configured to determine at least one characteristic of the spine of a patient having possible scoliosis based on said at least one x-ray image obtained by means of the photon-counting x-ray detector(s) to enable assessment of scoliosis.

Abstract: There is provided a method for processing a radiographic image acquired with at least two energy levels. A first step (S1) involves providing energy-resolved image data representative of the radiographic image with at least two energy levels, e.g. from a detector or from an intermediate storage. A second step (S2) involves decomposing the provided image data into at least one basis image representation, based on a model where a combination of at least two basis functions is used to express a representation of at least one linear attenuation coefficient, and where at least one basis function models a physical material and at least one other basis function models the Non-Linear Partial Volume, NLPV, effect.

Abstract: There is provided a method and corresponding system for data acquisition, for Computed Tomography, CT, based on an x-ray imaging system (10) having a detector (12) with a plurality of pixels (13), wherein data sampling is performed with a temporal offset between measurements acquired by adjacent pixels of the detector.

Abstract: Disclosed is an edge-on photon counting detector and a method for manufacturing a charge collecting side of such detector. The edge-on photon counting detector includes a semi-conducting substrate. The semi-conducting substrate includes, a first end adapted to face an x-ray source and a second end opposite the first end in the direction of incoming x-rays, and at least one strip having N depth segments, N?2, each of the depth segments including a charge collecting metal electrode and a charge collecting side including doped regions and insulating regions, wherein each of the charge collecting metal electrodes is arranged over a corresponding doped region and is connected to a respective routing trace arranged on the insulating regions, the respective routing trace being adapted to conduct signals from the charge collecting metal electrode to a read-out pad E, connectable to front-end electronics, arranged at the second end.

Abstract: Disclosed is an x-ray sensor having an active detector region including a plurality of detector diodes at a first side of the sensor, and with placement of the junction termination at a second opposite side of the sensor. Normally, this implies that the junction termination is moved from the top side where the active detector area is located to the bottom side of the sensor, allowing for full utilization of the active detector area at the top side with detector diodes to the very edge of the sensor.

Abstract: Disclosed is an x-ray detector system including a multitude of detector elements, each connected to a respective photon counting channel for providing at least one photon count output, and a read-out unit connected to the photon counting channels for outputting the photon count outputs. Each one of at least a subset of the photon counting channels includes at least two photon counting sub-channels, each photon counting sub-channel providing at least one photon count output and having a shaping filter, wherein the shaping filters of the photon counting sub-channels are configured with different shaping times, and wherein the photon counting sub-channels, having shaping filters with different shaping times, are adapted for counting photons of different energy levels. Furthermore, the read-out unit is configured to select, for each photon counting channel, photon count outputs from the photon counting sub-channels.

Abstract: There is provided an x-ray detector including a number of adjacent detector modules arranged in a configuration having central parts and peripheral parts. The x-ray detector is configured to have higher dose efficiency in the central parts and lower dose efficiency in the peripheral parts.

Abstract: Disclosed are methods and devices for estimating object scatter and/or internal scatter in a multi-level photon-counting x-ray detector, as well as x-ray tomographic imaging while correcting for object and internal scatter. The x-ray detector has at least two layers of detector diodes mounted in an edge-on geometry, e.g. designed for 1) estimating the object scatter contribution to the counts in a top layer of the at least two layers based on difference(s) in counts between the top layer and lower layer(s) under the assumption the object scatter has a slowly varying spatial distribution, and/or 2) estimating counts from reabsorption of photons that have Compton scattered inside the detector based on selectively blinding some detector elements from primary radiation by placing a highly attenuating beam stop on top of the detector elements, in lower layer(s) or in both top layer and lower layer(s), and measuring the counts in those detector elements.

Abstract: Disclosed are methods, systems, apparatuses and computer programs for estimating a measure of the gain and offset of a converter that generates, based on digital settings, reference voltages to be used as thresholds by a comparator in a photon-counting detector in an x-ray imaging system. Steps include selecting a first converter as a reference converter and a second converter as a target converter; assigning different digital settings to the reference converter to generate at least two different reference voltages to be used as thresholds by a comparator associated with the reference converter; and obtaining, based on photon count measurements, the number of photons registered in a photon counter associated with a comparator whose reference voltage is generated by the target converter. Based on the number of photons and the at least two digital settings, an estimate of the gain and offset of the target converter relative the reference converter results.

Abstract: There is provided a method for at least partly determining the orientation of an edge-on x-ray detector with respect to the direction of x-rays from an x-ray source. The method includes obtaining (S1) information from measurements, performed by the x-ray detector, representing the intensity of the x-rays at a minimum of two different relative positions of a phantom in relation to the x-ray detector and the x-ray source, the phantom being situated between the x-ray source and the x-ray detector and designed to embed directional information in the x-ray field when exposed to x-rays. The method also includes determining (S2) at least one parameter associated with the orientation of the x-ray detector with respect to the direction of x-rays based on the obtained information from measurements and a geometrical model of the spatial configuration of the x-ray detector, x-ray source and phantom.