# US 9,517,045 B2 · Radiographic imaging apparatus and a method of correcting threshold energies in a photon-counting radiographic detector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,045 B2 - Document ID: US9517045B2 - Status: Granted - Kind: B2 - Application number: 14/483,574 - Filed: 2014-09-11 - Published: 2015-05-28 - Granted: 2016-12-13 - Earliest claimed: 2013-11-25 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Ji Hoon Kang; Sang Min Lee; Min Kook Cho - Web page: https://patentgrep.com/patent/US9517045B2 ## CPC - A61B 6/585: {Calibration of detector units} - A61B 6/4233: {using matrix detectors} - A61B 6/4241: {using energy resolving detectors, e.g. photon counting} - A61B 6/58: Testing, adjusting or calibrating thereof - A61B 6/582: {Calibration} - G01N 23/087: using polyenergetic X-rays - G01T 7/00: Details of radiation-measuring instruments - G01T 7/005: {calibration techniques (stabilization of spectrometer G01T1/40)} - A61B 6/032: {Transmission computed tomography [CT]} - A61B 6/4452: {the source unit and the detector unit being able to move relative to each other} - A61B 6/4464: {the source unit or the detector unit being mounted to ceiling} - G01N 2223/205: natural source - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - 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 Provided are a radiographic imaging apparatus and a method of controlling the same. The radiographic imaging apparatus includes a radiographic source configured to emit radiographic rays in a discontinuous eigen energy spectrum, a radiographic detector configured to receive the radiographic rays, convert the received radiographic rays into electrical signals, and count the number of photons having energy that exceeds a threshold energy, and a controller configured to adjust the threshold energy by comparing an energy spectrum of the detected radiographic rays with the eigen energy spectrum of the emitted radiographic rays from the radiographic source. ## Claims ### Claim 1 A radiographic imaging apparatus comprising: a radiographic source configured to emit radiographic rays in a discontinuous eigen energy spectrum; a radiographic detector configured to receive the radiographic rays, convert the received radiographic rays into electrical signals, and count the number of photons having energies that exceed a threshold energy; and a controller configured to adjust the threshold energy by comparing an spectrum of the received radiographic rays with the eigen energy spectrum of the emitted radiographic rays from the radiographic source. ### Claim 2 (depends on 1) The radiographic imaging apparatus of claim 1, wherein the radiographic source comprises at least one radiographic isotope. ### Claim 3 (depends on 2) The radiographic imaging apparatus of claim 2, wherein the at least one radiographic isotope is at least one selected from the group consisting of americium-241, cadmium-109, and cobalt-57. ### Claim 4 (depends on 2) The radiographic imaging apparatus of claim 2, wherein the at least one radiographic isotope is at least one selected from the group consisting of a dot-shaped radiographic source, a line-shaped radiographic source, and a face-shaped radiographic source. ### Claim 5 (depends on 1) The radiographic imaging apparatus of claim 1, wherein the radiographic source further comprises: a shielding unit configured to shield the radiographic rays. ### Claim 6 (depends on 5) The radiographic imaging apparatus of claim 5, wherein the shielding unit is further configured to guide the radiographic rays along a radiation direction. ### Claim 7 (depends on 1) The radiographic imaging apparatus of claim 1, wherein the controller comprises: a spectrum generator configured to generate an energy spectrum according to pixels of the radiographic detector by varying the threshold energy; a comparator configured to compare the discontinuous eigen energy spectrum with the generated energy spectrum; and a correction unit configured to adjusts the threshold energy based on a result of comparison from the comparator according to the pixels of the radiographic detector. ### Claim 8 (depends on 7) The radiographic imaging apparatus of claim 7, wherein the controller further comprises: a mapping table in which values of the threshold energy are configured to be stored according to the pixels, and wherein the correction unit is further configured to update the mapping table according to the adjusted threshold energy. ### Claim 9 (depends on 8) The radiographic imaging apparatus of claim 8, wherein the controller further comprises: a testing unit configured to set threshold energy of the pixels according to the updated mapping table and determine whether errors of the pixels are within a predetermined range. ### Claim 10 (depends on 1) The radiographic imaging apparatus of claim 1, further comprising: a movement unit that moves the radiographic source so that the radiographic rays emitted from the radiographic source are uniformly radiated onto the radiographic detector. ### Claim 11 A method of controlling a radiographic imaging apparatus, wherein the radiographic imaging apparatus receives radiographic rays and counts the number of photons having energies that exceed a threshold energy based on the received radiographic rays, the method comprising: detecting, using a radiographic detector, an energy spectrum of radiographic rays in a discontinuous energy spectrum; and adjusting, using a controller, the threshold energy by comparing the detected energy spectrum of the radiographic rays in the discontinuous energy spectrum with an eigen energy spectrum of the radiographic rays. ### Claim 12 (depends on 11) The method of claim 11, wherein detecting the energy spectrum comprises: varying the threshold energy at predetermined intervals; and monitoring the number of photons counted in pixels of the radiographic detector. ### Claim 13 (depends on 11) The method of claim 11, wherein the adjusting the threshold energy comprises: calculating a difference value between the detected energy spectrum of the radiographic rays in the discontinuous energy spectrum with the eigen energy spectrum of the radiographic rays; and determining threshold energy of the pixels based on the difference value. ### Claim 14 (depends on 13) The method of claim 13, wherein the determining the threshold energy comprises: determining the threshold energy of the pixels by substituting the difference value for a parameter of a predetermined function. ### Claim 15 (depends on 11) The method of claim 11, wherein the adjusting the threshold energy comprises: updating a mapping table in which the threshold energy is stored according to the pixels. ### Claim 16 (depends on 15) The method of claim 15, wherein the adjusting the threshold energy further comprises: checking whether errors of the pixels are within a predetermined range, by setting the threshold energy according to the updated mapping table. ### Claim 17 (depends on 11) The method of claim 11, further comprising: counting the number of photons included in the radiographic rays transmitted by an object based on the adjusted threshold energy; and generating a radiographic image based on the counted number of photons. ### Claim 18 A radiographic imaging apparatus comprising: a radiation source configured to transmit radiation at a transmission energy level; a detector configured to receive, at a pixel of the detector, the radiation at a received energy level; a controller configured to store an energy spectrum of the radiation, wherein the energy spectrum is generated by comparing the transmission energy level and the received energy level and determining a difference, generating a correction value using the difference, adjusting the received energy level using the correction value, and storing the adjusted received energy level into the energy spectrum. ### Claim 19 (depends on 18) The radiographic imaging apparatus of claim 18, wherein the controller is configured to store the adjusted received energy level into the energy spectrum in response to a change in the adjusted received energy level compared to a previous energy level is over a threshold. ### Claim 20 (depends on 18) The radiographic imaging apparatus of claims 18, wherein the radiation source is further configured to transmit radiation at a plurality of transmission energy levels, and wherein the detector is further configured to receive, at a plurality of pixels of the detector, the radiation at a plurality of received energy levels.