Abstract: A method for extending initial image data of a subject for dose estimation includes obtaining first image data of the subject for dose calculation, wherein the first image data has a first field of view. The method further includes obtaining second image data for extending the field of view of the first image data. The second image data has a second field of view that is larger than the first field of view. The method further includes extending the first field of view based on the second image data, producing extended image data.

Abstract: A filter assembly for use in a helical computed tomography system having an x-ray source for projecting x-ray beams along a projection axis is presented, the filter assembly including a first filter element for attenuating at least a portion of the x-ray beams, the first filter element constructed as a background-wedge for attenuating x-rays having a large aperture and a second filter element for attenuating at least a portion of the x-ray beams, the second filter element constructed to create a ridge. The second filter element may be rotated with respect to or adjusted in relation with or removed or replaced from the filter assembly to allow for adaptation to different helical pitch values.

Abstract: An imaging system (100) includes a direct conversion detector pixel (111) that detects radiation traversing an examination region and generates an electrical signal indicative thereof, wherein the signal includes a persistent current, which is produced by a direct conversion material of the pixel and which shifts a level of the signal. A persistent current estimator (116) estimates the persistent current and generates a compensation signal based on the estimate. A pre-amplifier (112) receives the signal and the compensation signal, wherein the compensation signal substantially cancels the persistent current, producing a persistent current compensated signal, and that amplifies the compensated signal, generating an amplified compensated signal. A shaper (114) generates a pulse indicative of energy of the radiation illuminating the direct conversion material based on the amplified compensated signal.

Abstract: An imaging system (100) includes a detector array (110) that detects radiation traversing an examination region. The detector array includes at least a set of non-spectral detectors (112) that detects a first sub-portion of the radiation traversing the examination region and generates first signals indicative thereof. The detector array further includes at least a set of spectral detectors (114) that detects a second sub-portion of the radiation traversing the examination region and generates second signals indicative thereof. The imaging system further includes a reconstructor (120) that processes the first and second signals, generating volumetric image data.

Abstract: The invention relates to an X-ray imaging apparatus and a method, particularly to a CT scanner (100) for generating sectional images of an object such as the body (P) of a patient. A given desired angular intensity distribution (Ides) is reproduced by emitting X-rays (X) in emission angle intervals (EAI) only, wherein the angular distribution of these emission angle intervals and the associated local emission intensities (I(?)) are chosen such that they reproduce, in the angular mean, the desired angular intensity distribution (Ides). Modulation of incident X-ray flux is hence realized by the modulation of the angular sampling density. The X-ray source may preferably be realized by a grid switching tube (101).

Abstract: The invention relates to a detection values processing apparatus. Energy-dependent detection values are provided, which are indicative of polychromatic radiation (4) after having traversed an examination zone (5). The radiation is filtered by a filter (15) which comprises K-edge filter material. A component decomposition technique is applied to the detection values for determining K-edge attenuation values being first component attenuation values, which are indicative of an attenuation caused by the K-edge filter material, and additional component attenuation values, which are indicative of an attenuation caused by additional components of the examination zone, wherein an image of the examination zone is reconstructed from the additional component attenuation values. An image can therefore be reconstructed, which is not adversely affected by the filter, because the K-edge attenuation values are not used for reconstructing the image. This can improve the quality of the reconstructed image.

Abstract: A method includes reconstructing measured projection data using an iterative statistical reconstruction algorithm that reduces image artifact caused by differences in variances in projections of the measured projection data used to update a voxel of the image for one or more voxels of the image. A reconstructor includes a processor that reconstructs measured projection data using an iterative statistical reconstruction algorithm that reduces or mitigates image artifact caused by differences in variances in projections used to update a voxel of the image for one or more voxels of the image. A computer readable storage medium encoded with computer executable instructions, which, when executed by a processor of a computer, cause the processor to: reduce image artifact caused by differences in variances in projections used to update a voxel of an image for one or more voxels of the image using an iterative statistical reconstruction algorithm.

Abstract: An imaging system (100) includes a direct conversion detector pixel (111) that detects radiation traversing an examination region and generates an electrical signal indicative thereof, wherein the signal includes a persistent current, which is produced by a direct conversion material of the pixel and which shifts a level of the signal. A persistent current estimator (116) estimates the persistent current and generates a compensation signal based on the estimate. A pre-amplifier (112) receives the signal and the compensation signal, wherein the compensation signal substantially cancels the persistent current, producing a persistent current compensated signal, and that amplifies the compensated signal, generating an amplified compensated signal. A shaper (114) generates a pulse indicative of energy of the radiation illuminating the direct conversion material based on the amplified compensated signal.

Abstract: The present invention discloses a method for reconstructing an image obtained from kVp switched imaging of a body by acquiring a plurality of images at a first kVp defining a first image scan and a plurality of images at a second kVp defining a second image scan, wherein the plurality of images at the first kVp are acquired interleaved with the plurality of images of the second image scan and by reconstructing an image from the first and second image scan, comprising determining at least one gradient location for at least two images in the first and second image scans, determining divergent gradient locations in respect of a same part of the body for said at least two images in the first and second image scans, tagging each divergent gradient location as an under sampling artifact, generating the reconstructed image from the at least two images in the first and second image scans by correcting for each tagged under sampling artifact.

Abstract: The noise of a detection value acquired by an imaging system (30) can depend on the contributions of different components within a region of interest to be imaged, which has been traversed by radiation (4) causing the respective acquired detection value. This dependence is considered while iteratively reconstructing an image of the region of interest, wherein first component attenuation values, which correspond to elements of a first component within the region of interest, and second component attenuation values, which correspond to elements of a first component within the region of interest, are determined, wherein noise values are determined from the first component attenuation values and the second component attenuation values and wherein the noise values are used for updating the image. This consideration of the dependence of the noise of an acquired detection value on the different components improves the quality of the iteratively reconstructed image.

Abstract: An imaging system including a source (310) having a focal spot (406) that emits a radiation beam that traverses an examination region, a radiation sensitive detector array (316) having a plurality of pixels that detects radiation traversing the examination region and generates projection data indicative of the detected radiation, and a filter (314), disposed between the source and the examination region, that filters peripheral regions of the emitted radiation, wherein the filter includes two separate and moveable regions (402), each region having a substantially same thickness and constant homogeneity.

Abstract: The invention relates to an imaging apparatus (31) for imaging an object. A reconstruction unit (12) determines component projection data values, which correspond to, for example, a base material of the object, and reconstructs an image of the object based on the determined component projection data values. A component projection data value, which corresponds to a ray, is determined as a combination of weighted base functions, which depend on energy projection data values of the same ray and the orientation of the same ray. This allows considering a possible dependency of the corresponding decomposition on the orientation of the ray, thereby allowing the imaging apparatus to improve the quality of decomposing the provided energy projection data values into the component projection data values and thus of a finally reconstructed image of the object, which is reconstructed based on the component projection data values.

Abstract: The invention relates to a detection apparatus comprising a filter (20) for filtering a conical radiation beam (4) such that at least a first region (22) and a second region (23) of the radiation beam are generated having different energy spectra, wherein the first region of the radiation beam illuminates a first detector area (25) on a detection surface (21) of a detector, thereby generating a first set of detection values, and the second region of the radiation beam illuminates a second detector area (26) on the detection surface, thereby generating a second set of detection values. For example, by using the filter the detection apparatus can be used as dual-energy computed tomography apparatus, wherein, for instance, a standard computed tomography apparatus can be transformed to a dual-energy computed tomography apparatus by adding the filter to the standard computed tomography apparatus, preferentially without modifying the radiation source and the detector.

Abstract: The present invention relates to a radiographic imaging apparatus and a corresponding radiographic imaging method. The proposed apparatus comprises an X-ray source (20, 108) and a photon counting X-ray detector (40, 110). The X-ray source (20, 108) comprises a rotary X-ray anode (23) having a number of radial slits and a target layer provided on a surface of said rotary X-ray anode in between said radial slits for emitting X-ray radiation when hit by said electron beam. The said photon counting X-ray detector (40, 110) comprises a persistent current sensing and correction unit (70) for sensing a persistent output current in a blanking interval during which no X-ray radiation is emitted by said X-ray source and for using the sensed persistent output current to correct a detector signal in a subsequent measurement interval during which X-ray radiation is emitted by said X-ray source.

Abstract: An imaging system (100) includes a direct conversion detector pixel (111) that detects radiation traversing an examination region and generates an electrical signal indicative thereof, wherein the signal includes a persistent current, which is produced by a direct conversion material of the pixel and which shifts a level of the signal. A persistent current estimator (116) estimates the persistent current and generates a compensation signal based on the estimate. A pre-amplifier (112) receives the signal and the compensation signal, wherein the compensation signal substantially cancels the persistent current, producing a persistent current compensated signal, and that amplifies the compensated signal, generating an amplified compensated signal. A shaper (114) generates a pulse indicative of energy of the radiation illuminating the direct conversion material based on the amplified compensated signal.

Abstract: A method includes generating a first measurement spectral image from first spectral image data based on a predetermined measurement energy. The method further includes determining a first measurement value for a first region of interest in the first measurement spectral image. The method further includes overlying the first measurement value in connection with a corresponding first region of interest in a visually presented first display spectral image, wherein the measurement energy is different from a first display energy of the first display spectral image.

Abstract: An apparatus (T) and method for correcting detector (104) measurement data for errors caused by imperfections in the detector (104) that effect the accuracy of the detector readings.

Abstract: The present invention discloses a method for reconstructing an image obtained from kVp switched imaging of a body by acquiring a plurality of images at a first kVp defining a first image scan and a plurality of images at a second kVp defining a second image scan, wherein the plurality of images at the first kVp are acquired interleaved with the plurality of images of the second image scan and by reconstructing an image from the first and second image scan, comprising determining at least one gradient location for at least two images in the first and second image scans, determining divergent gradient locations in respect of a same part of the body for said at least two images in the first and second image scans, tagging each divergent gradient location as an under sampling artifact, generating the reconstructed image from the at least two images in the first and second image scans by correcting for each tagged under sampling artifact.

Abstract: A method includes concurrently modulating administration of at least two different contrast agents to a subject during an imaging procedure based on a modulation profile. The at least two different contrast agents exhibit different spectral characteristics. The method further includes performing a spectral decomposition of data indicative of the at least two different contrast agents, determining concentrations of the at least two different contrast agents based on the spectral reconstruction, and determining a perfusion parameter based on a ratio of the concentrations and the modulation profile.

Abstract: An imaging system includes a radiation source (310) configured to rotate around an examination region about a z-axis and having a focal spot that emits a radiation beam that traverses the examination region. The system further includes a radiation sensitive detector array (314) with a plurality of detector pixels that detects radiation traversing the examination region and generates projection data indicative of the detected radiation. The system further includes a dynamic post-patient filter (316) including one or more filter segments (402, 802, 902, 1004, 1102). The filter is configured to selectively and dynamically move in front of the detector array between the detector array and the examination region and into and out of a path of the radiation beam illuminating the detector pixels during scanning an object or subject based on a shape of the object or subject, thereby filtering unattenuated radiation and radiation traversing a periphery of the object or subject.