# US 2019/0172231 A1 · Method for correcting a spatially resolved photon scan of an x-ray detector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0172231 A1 - Document ID: US20190172231A1 - Status: Published application - Kind: A1 - Application number: 16/202,246 - Filed: 2018-11-28 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Siemens Healthcare GmbH - Applicants: Siemens Healthcare GmbH - Inventors: Christoph POLSTER; Steffen KAPPLER; Edgar GOEDERER - Web page: https://patentgrep.com/patent/US20190172231A1 ## CPC - G06T 12/30: Image post-processing, e.g. metal artefact correction - A61B 6/032: {Transmission computed tomography [CT]} - A61B 6/4233: {using matrix detectors} - A61B 6/4241: {using energy resolving detectors, e.g. photon counting} - A61B 6/5205: {involving processing of raw data to produce diagnostic data} - A61B 6/5258: {involving detection or reduction of artifacts or noise} - G01T 1/17: Circuit arrangements not adapted to a particular type of detector {(pulse-selection circuits H03K, G01R)} - G06T 12/10: Image preprocessing, e.g. calibration, positioning of sources or scatter correction - G06T 2207/10081: Computed x-ray tomography [CT] - G06T 2210/41: Medical - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) ## Abstract A method and an X-ray detector are for correcting a spatially resolved photon scan of the X-ray detector. In an embodiment, the X-ray detector includes processing circuitry configured to: generate, from an incident X-ray photon, a signal contribution in a first electrical signal in a spatially resolved manner, a reference value being defined by an absence of X-ray photons; resolve, in relation to the reference value, positive signal contributions of the first electrical signal and negative signal contributions of the first electrical signal; and provide the positive signal contributions resolved and the negative signal contributions resolved for further processing. ## Claims ### Claim 1 A method for correcting a spatially resolved photon scan of an X-ray detector, comprising: generating in the X-ray detector, from an incident X-ray photon, a signal contribution of a first electrical signal in a spatially resolved manner, a reference value for the first electrical signal being defined by an absence of X-ray photons; selecting, for the first electrical signal, an upper threshold value above the reference value and selecting a lower threshold value below the reference value; first comparing the first electrical signal in a spatially resolved manner with the upper threshold value; generating, upon the first comparing indicating that the upper threshold value is exceeded, a signal contribution of a second electrical signal, spatially resolved; second comparing the first electrical signal, in a spatially resolved manner with the lower threshold value; generating, upon the second comparing indicating that the lower threshold value is undershot, a signal contribution of a correction signal; correcting the second electrical signal based upon the correction signal; and generating, based upon the second electrical signal corrected, an image data set. ### Claim 2 (depends on 1) The method of claim 1, wherein the signal contribution of the first electrical signal is generated in a quantum-counting manner. ### Claim 3 (depends on 1) The method of claim 1, wherein a ratio of an amount of the lower threshold value and an amount of the upper threshold value, each relative to the reference value, is selected to be between 0.3 and 3. ### Claim 4 (depends on 1) The method of claim 1, wherein the lower threshold value is selected to be in an interval from 5 keV to 15 keV below the reference value. ### Claim 5 (depends on 1) The method of claim 1, wherein the second electrical signal is locally corrected by the correction signal in a pixel electronics unit of the X-ray detector, and based upon the second electrical signal locally corrected, a third electrical signal is generated, and wherein the image data set is generated based upon the third electrical signal. ### Claim 6 (depends on 1) The method of claim 1, wherein the second electrical signal and the correction signal are each passed on by a pixel electronics unit (of the X-ray detector to an application-specific integrated circuit, wherein the second electrical signal is locally corrected in the application-specific integrated circuit, and based upon the second electrical signal locally corrected, a third electrical signal is generated, and wherein the image data set is generated based upon the third electrical signal. ### Claim 7 (depends on 1) The method of claim 1, wherein the second electrical signal and the correction signal are each transferred by an application-specific integrated circuit to a central signal processing unit, wherein the second electrical signal is corrected in the central signal processing unit, and based upon the second electrical signal corrected, a third electrical signal is generated, and wherein the image data set is generated based upon the third electrical signal. ### Claim 8 (depends on 1) The method of claim 1, wherein the second electrical signal and the correction signal are each transferred by a central signal processing unit on a rotating part of a computed tomography system to a fixed part of the computed tomography system, wherein the second electrical signal is corrected on the fixed part of the computed tomography system, and based upon the second electrical signal corrected, a third electrical signal is generated and wherein the image data set is generated based upon the third electrical signal. ### Claim 9 (depends on 1) The method of claim 1, wherein the second electrical signal and the correction signal are each transferred to an image processing unit, wherein a data set of preliminary image data is generated from the second electrical signal, wherein a correction image data set is generated from the correction signal, and wherein the image data set is generated from the data set of preliminary image data and the correction image data set. ### Claim 10 An X-ray detector for spatially resolved detection of X-ray photons, the X-ray detector comprising: processing circuitry configured to: generate, from an incident X-ray photon, a signal contribution in a first electrical signal in a spatially resolved manner, a reference value being defined by an absence of X-ray photons; resolve, in relation to the reference value, positive signal contributions of the first electrical signal and negative signal contributions of the first electrical signal; and provide the positive signal contributions resolved and the negative signal contributions resolved for further processing. ### Claim 11 (depends on 10) The X-ray detector of claim 10, further comprising: a converting detector material to generate charge carriers from an incident X-ray photon; a spatially resolving electrode arrangement; and a plurality of current-voltage converters, wherein the processing circuitry is further configured to generate a spatially resolved signal contribution in the first electrical signal from the charge carriers generated through the incident X-ray photon, and spatially resolved via the spatially resolving electrode arrangement, to generate a current pulse, and generate, based upon the current pulse converted via one of the plurality of current-voltage converters, a voltage pulse as a signal contribution in the first electrical signal. ### Claim 12 (depends on 11) The X-ray detector of claim 11, wherein the plurality of current-voltage converters are each configured, based upon a unipolar current pulse generated by an incident X-ray photon, to generate a unipolar voltage pulse and, based upon a bipolar current pulse, to generate a bipolar voltage pulse. ### Claim 13 (depends on 12) The X-ray detector of claim 12, wherein the plurality of current-voltage converters are each integrated into an application-specific integrated circuit, each including an amplifier stage. ### Claim 14 (depends on 10) An imaging medical device comprising: an X-ray source for generating X-ray photons; and the X-ray detector of claim 10. ### Claim 15 (depends on 14) The imaging medical device of claim 14, configured as a computed tomography system. ### Claim 16 (depends on 14) The imaging medical device of claim 14, configured as a C-arm device. ### Claim 17 (depends on 2) The method of claim 2, wherein a ratio of an amount of the lower threshold value and an amount of the upper threshold value, each relative to the reference value, is selected to be between 0.3 and 3. ### Claim 18 (depends on 17) The method of claim 17, wherein the lower threshold value is selected to be in an interval from 5 keV to 15 keV below the reference value. ### Claim 19 (depends on 2) The method of claim 2, wherein the lower threshold value is selected to be in an interval from 5 keV to 15 keV below the reference value. ### Claim 20 (depends on 2) The method of claim 2, wherein the second electrical signal is locally corrected by the correction signal in a pixel electronics unit of the X-ray detector, and based upon the second electrical signal locally corrected, a third electrical signal is generated, and wherein the image data set is generated based upon the third electrical signal. ### Claim 21 (depends on 2) The method of claim 2, wherein the second electrical signal and the correction signal are each passed on by a pixel electronics unit (of the X-ray detector to an application-specific integrated circuit, wherein the second electrical signal is locally corrected in the application-specific integrated circuit by the correction signal, and based upon the second electrical signal locally corrected, a third electrical signal is generated, and wherein the image data set is generated based upon the third electrical signal. ### Claim 22 (depends on 2) The method of claim 2, wherein the second electrical signal and the correction signal are each transferred by an application-specific integrated circuit to a central signal processing unit, wherein the second electrical signal is corrected in the central signal processing unit, and based upon the second electrical signal corrected, a third electrical signal is generated, and wherein the image data set is generated based upon the third electrical signal. ### Claim 23 (depends on 2) The method of claim 2, wherein the second electrical signal and the correction signal are each transferred by a central signal processing unit on a rotating part of a computed tomography system to a fixed part of the computed tomography system, wherein the second electrical signal is corrected on the fixed part of the computed tomography system, and based upon the second electrical signal corrected, a third electrical signal is generated and wherein the image data set is generated based upon the third electrical signal. ### Claim 24 (depends on 2) The method of claim 2, wherein the second electrical signal and the correction signal are each transferred to an image processing unit, wherein a data set of preliminary image data is generated from the second electrical signal, wherein a correction image data set is generated from the correction signal, and wherein the image data set is generated from the data set of preliminary image data and the correction image data set. ### Claim 25 (depends on 11) An imaging medical device comprising: an X-ray source for generating X-ray photons; and the X-ray detector of claim 11. ### Claim 26 (depends on 12) An imaging medical device comprising: an X-ray source for generating X-ray photons; and the X-ray detector of claim 12. ### Claim 27 (depends on 13) An imaging medical device comprising: an X-ray source for generating X-ray photons; and the X-ray detector of claim 13.