# US 9,039,284 B2 · Method for energy calibrating quantum-counting x-ray detectors in a dual-source computed-tomography scanner > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,039,284 B2 - Document ID: US9039284B2 - Status: Granted - Kind: B2 - Application number: 13/795,203 - Filed: 2013-03-12 - Published: 2013-09-26 - Granted: 2015-05-26 - Earliest claimed: 2012-03-20 - Assignees: Siemens Aktiengesellschaft - Applicants: Mario Eichenseer; Steffen Kappler; Edgar Kraft; Björn Kreisler; Daniel Niederlöhner; Stefan Wirth - Inventors: Mario Eichenseer; Steffen Kappler; Edgar Kraft; Björn Kreisler; Daniel Niederlöhner; Stefan Wirth - Web page: https://patentgrep.com/patent/US9039284B2 ## CPC - G01T 7/005: {calibration techniques (stabilization of spectrometer G01T1/40)} - G01T 1/2985: {In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); (using external radiation sources A61B6/02)} - 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 is disclosed for energy calibrating quantum-counting x-ray detectors in an x-ray installation including at least two x-ray systems turnable around a center of rotation. A target, for producing x-ray fluorescence radiation, is positioned between the first x-ray source and first x-ray detector and irradiated with x-radiation of the first x-ray source in such a way that x-ray fluorescence radiation which strikes the second x-ray detector from the target is produced by the x-radiation of the first x-ray source. The second x-ray detector is then energy calibrated by way of the x-ray fluorescence radiation of the target. The first x-ray detector can be energy calibrated in the same way with the aid of the x-radiation of the second x-ray source. With the proposed method, the x-ray detectors of a dual-source CT x-ray installation can be calibrated with little expenditure under conditions close to those of the system. ## Claims ### Claim 1 A method for energy calibrating quantum-counting x-ray detectors in an x-ray installation including at least two x-ray systems that can be turned around a center of rotation and are arranged including a mutual angular offset in a direction of rotation and of which a first x-ray system includes a first x-ray source and an opposing first x-ray detector and a second x-ray system includes a second x-ray source and a second opposing x-ray detector, the method comprising: positioning a target for producing x-ray fluorescence radiation between the first x-ray source and first x-ray detector; irradiating the target with x-radiation of the first x-ray source in such a way that x-ray fluorescence radiation, which strikes the second x-ray detector from the target, is produced by the x-radiation of the first x-ray source; and energy calibrating the second x-ray detector by way of the x-ray fluorescence radiation of the target. ### Claim 2 (depends on 1) The method of claim 1, wherein the second x-ray detector is conditioned before or while being calibrated by operation of the second x-ray source. ### Claim 3 (depends on 2) The method of claim 2, wherein the target is positioned between the first x-ray source and first x-ray detector such that, with no change to position or orientation, the target is irradiateable with x-radiation of the second x-ray source after the second x-ray detector has been calibrated and x-ray fluorescence produced thereby will strike the first x-ray detector, and wherein the target will be irradiated with x-radiation of the second x-ray source after the second x-ray detector has been calibrated and the first x-ray detector will be energy calibrated by way of the produced x-ray fluorescence radiation of the target. ### Claim 4 (depends on 2) The method of claim 2, wherein after the second x-ray detector has been calibrated, the target for producing the x-ray fluorescence radiation is positioned between the second x-ray source and second x-ray detector and irradiated with x-radiation of the second x-ray source in such a way that x-ray fluorescence radiation which strikes the first x-ray detector is produced by the x-radiation of the second x-ray source and the first x-ray detector is energy calibrated by way of the x-ray fluorescence radiation of the target. ### Claim 5 (depends on 1) The method of claim 1, wherein the target is positioned between the first x-ray source and first x-ray detector such that, with no change to position or orientation, the target is irradiateable with x-radiation of the second x-ray source after the second x-ray detector has been calibrated and x-ray fluorescence produced thereby will strike the first x-ray detector, and wherein the target will be irradiated with x-radiation of the second x-ray source after the second x-ray detector has been calibrated and the first x-ray detector will be energy calibrated by way of the produced x-ray fluorescence radiation of the target. ### Claim 6 (depends on 5) The method of claim 5, wherein the first x-ray detector is conditioned before or while being calibrated by operation of the first x-ray source. ### Claim 7 (depends on 1) The method of claim 1, wherein after the second x-ray detector has been calibrated, the target for producing the x-ray fluorescence radiation is positioned between the second x-ray source and second x-ray detector and irradiated with x-radiation of the second x-ray source in such a way that x-ray fluorescence radiation which strikes the first x-ray detector is produced by the x-radiation of the second x-ray source and the first x-ray detector is energy calibrated by way of the x-ray fluorescence radiation of the target. ### Claim 8 (depends on 7) The method of claim 7, wherein the first x-ray detector is conditioned before or while being calibrated by operation of the first x-ray source. ### Claim 9 (depends on 1) The method of claim 1, wherein a target, including at least two regions composed of different materials, is used for producing the x-ray fluorescence radiation. ### Claim 10 (depends on 9) The method of claim 9, wherein the at least two regions are arranged such that, by setting at least one beam mask in front of at least one of the first and second x-ray source, in each case the x-ray fluorescence radiation striking at least one of the first and second x-ray detector can be limited to each of the regions. ### Claim 11 (depends on 10) The method of claim 10, wherein at least two of the regions are irradiated successively by changing the setting of the beam mask in front of at least one of the first and second x-ray source. ### Claim 12 (depends on 9) The method of claim 9, wherein regions including a material suitable for producing the x-ray fluorescence radiation alternate with regions that are permeable to the x-radiation of at least one of the first and second x-ray source.