Abstract: A method includes analyzing a spectral projection image of a portion of a subject, generating a value quantifying an amount of a target specific contrast material in a region of interest of the spectral projection image, and generating a signal indicative of a presence of the target in response to the value satisfying a predetermined threshold level.

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 detecting radiation that traverses a material having a known spectral characteristic with a radiation sensitive detector pixel that outputs a signal indicative of the detected radiation and determining a mapping between the output signal and the spectral characteristic. The method further includes determining an energy of a photon detected by the radiation sensitive detector pixel based on a corresponding output of the radiation sensitive detector pixel and the mapping.

Abstract: The invention relates to a radiation detector (200), particularly an X-ray detector, which comprises at least one sensitive layer (212) for the conversion of incident photons (X) into electrical signals. A two-dimensional array of electrodes (213) is located on the front side of the sensitive layer (212), while its back side carries a counter-electrode (211). The size of the electrodes (213) may vary in radiation direction (y) for adapting the counting workload of the electrodes. Moreover, the position of the electrodes (213) with respect to the radiation direction (y) provides information about the energy of the detected photons (X).

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 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.

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 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: An imaging system includes a radiation source (106, T1, T2, T3) that rotates about an examination region and emits radiation that traverses the examination region. The radiation source (106, T1, T2, T3) emits radiation having an energy spectrum that is selectively alternately switched between at least two different energy spectra during an imaging procedure. The system further includes an energy-resolving detector array (116, D1, D2, D3) that detects radiation traversing the examination region. The energy-resolving detector array (116, D1, D2, D3) resolves the detected radiation over at least two different energy ranges and produces energy-resolved output signals as a function of both emission energy spectrum and energy range. The system further includes a reconstructor (126) that performs a spectral reconstruction of the energy-resolved output signals. In another embodiment, the detector array (116) includes a photon-counting detector array (116).

Abstract: The present application relates to a combined anti-scatter grid, cathode, and carrier for a photon detector used in spectral CT imaging. The photon detector of the present application may include a cathode having at least one outwardly extending plate and at least one base plate, a substrate having at least one anode, and a converter material, such as for example, Cadmium Zinc Telluride (“CZT”) or Cadmium Telluride. The at least one outwardly extending plate of the cathode may extend above the other detector components to act as an anti-scatter grid for the detector. Further, the at least one outwardly extending plate of the cathode may extend below the other detector components and be fixed to the at least one base plate of the detector. The converter material may be attached to at least one side of the at least one outwardly extending plate of the cathode.

Abstract: An imaging detector includes a radiation sensitive region having first and second opposing sides. One of the first or second sides senses impinging radiation. The detector further includes electronics located on the other of the first or second sides of the radiation sensitive region. The electronics includes a thermal controller that regulates a temperature of the imaging detector.

Abstract: A scanning method and apparatus useful for correcting artifacts which may appear in a primary short circular CT scan are provided. A secondary helical scan performed on a stationary subject, or a secondary circular scan, may be used to correct for artifacts. The secondary scan may be performed with a smaller radiation dosage than the primary circular CT scan.

Abstract: To mitigate the influence of charge sharing occurring in semiconductor detectors, an improved semiconductor detector (200) is provided, which comprises: a plurality of anodes (210) arranged to form at least one opening (230), each opening being formed by two anodes in the plurality of anodes; at least one cathode (220); a detector cell (240) located between the plurality of anodes and the at least one cathode; wherein the detector cell comprises at least one groove (250), each of the at least one groove having a first opening (252) aligned with one of the at least one opening being formed by two anodes in the plurality of anodes, each of the at least one groove extending towards the at least one cathode. By forming grooves in the detector cell, the charge cloud generated by a single photon can be received by a corresponding anode instead of several neighboring anodes, which thereby improves the spectral resolution and count rate of a semiconductor detector.

Abstract: An apparatus includes a local minimum identifier (408) that identifies a local minimum between overlapping pulses in a signal, wherein the pulses have amplitudes that are indicative of the energy of successively detected photons from a multi-energetic radiation beam by a radiation sensitive detector, and a pulse pile-up error corrector (232) that corrects, based on the local minimum, for a pulse pile-up energy-discrimination error when energy-discriminating the pulses using at least two thresholds corresponding to different energy levels. This technique may reduce spectral error when counting photons at a high count rate.

Abstract: A tomographic apparatus (10) includes at least two x-ray sources (16) that are concurrently driven with different switching patterns to generate uniquely encoded radiation. The tomographic apparatus (10) further includes at least two detectors (20) that each detect primary radiation emitted by its corresponding one of the at least two x-ray sources (16) and cross scatter radiation from at least one of the other at least two x-ray sources (16). Each of the at least two detectors (20) produces an aggregate signal representative of the detected primary and cross scatter radiation. The tomographic apparatus (10) further includes a decoupler (30) which, based on the different switching patterns, identifies at least one signal corresponding to at least one of the at least two x-ray sources (16) within the aggregate signal and associates the identified signal with its corresponding x-ray source (16).

Abstract: The invention relates to a computed tomography apparatus for imaging an object. The computed tomography apparatus comprises a radiation source (2) for generating modulated radiation (4) traversing the object and a detector (6) for generating detection values depending on the radiation (4) after having traversed the object, while the radiation source (2) and the object are moved relative to each other. A weight providing unit (14) provides modulation weights for weighting the detection values depending on the modulation of the radiation (4) and a reconstruction unit (15) reconstructs an image of the object, wherein the detection values are weighted based on the provided modulation weights and an image of the object is reconstructed from the weighted detection values. This can allow to optimize the dose application to the object by modulating the radiation accordingly, wherein the reconstructed images still have a high quality.

Abstract: An imaging system includes at least one radiation generating component (210) that alternately emits different radiation that traverse an examination region and a common detector (214) that detects radiation that traverses the examination region and generates a signal indicative thereof. Pulse generating circuitry (304) generates a pulse train, including a plurality of pulses, with a frequency indicative of the signal for the at least one radiation generating component (210) for a sampling interval. Processing electronics (220) determine an approximation of the signal for one of the at least one radiation generating components (210) for the sampling interval based on a number of pulses in the pulse train for the sampling interval and charge of the pulses in the pulse train.

Abstract: The present invention relates to a medical X-ray examination apparatus and method for performing k-edge imaging of an object of interest including material showing k-edge absorption. To allow the use of conventional detector technology, which does not suffer from the limitation to provide very high k-rate capabilities a method is proposed comprising the steps of: —emitting polychromatic X-ray radiation (4; 4a, 4b), —Bragg filtering said polychromatic X-ray radiation by a Bragg filter such that radiation (16) transmitted through said Bragg filter (14; 14a, 14b) passes through said object (5), —detecting X-ray radiation after passing through said object (5), —acquiring projection data at at least two different Bragg reflection angles of said Bragg filter (14; 14a, 14b), and —reconstructing a k-edge image from the acquired projection data.

Abstract: The invention relates to an image generation system for generating an image of a region of interest. The image generation system comprises a measured data providing unit for providing measured data of the region of interest, a reconstruction unit (12) for reconstructing a first and a second image of the region of interest from the measured data using a first and a second reconstruction method, a noise determination unit (13) for determining first and second noise values for first and second image elements of the first and second image, and an image element combining unit (14) for combining corresponding first and second image elements into combined image elements forming a combined image based on the first and second noise values. By combining corresponding image elements of two differently reconstructed images based on determined noise values, a combined image of a region of interest can be generated with an improved quality.

Abstract: An imaging system including a radiation source (110) that emits poly-chromatic radiation that traverses an examination region and a detector (116) that detects radiation traversing the examination region and produces a signal indicative of the energy of a detected photon. The system further includes an energy discriminator (122) that energy resolves the signal based on a plurality of different energy thresholds, wherein at least two of the energy thresholds have values corresponding to at least two different K-edge energies of two different elements in a mixture disposed in the examination region. The system also includes a signal decomposer (132) that decomposes the energy-resolved signal into at least a multi K-edge component representing the at least two different K-edge energies. In one instance, a stoichiometric ratio of the two different elements in the contrast agent is known and substantially constant.