Abstract: There is provided a method and corresponding system for image reconstruction based on energy-resolved x-ray data. The method comprises collecting (S1) at least one representation of energy-resolved x-ray data, and performing (S2) at least two basis material decompositions based on said at least one representation of energy-resolved x-ray data to generate at least two original basis image representation sets. The method further comprises obtaining or selecting (S3) at least two basis image representations from at least two of said original basis image representation sets, and processing (S4) said obtained or selected basis image representations by data processing based on machine learning to generate at least one representation of output image data.

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 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: 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 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: 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.