# US 11,298,097 B2 · Automated determination of an X-ray tube-current profile > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,298,097 B2 - Document ID: US11298097B2 - Status: Granted - Kind: B2 - Application number: 17/217,032 - Filed: 2021-03-30 - Published: 2021-10-07 - Granted: 2022-04-12 - Earliest claimed: 2020-04-07 - Assignees: Siemens Healthcare GmbH - Applicants: Siemens Healthcare GmbH - Inventors: Andreas Krauss - Web page: https://patentgrep.com/patent/US11298097B2 ## CPC - A61B 6/54: {Control of apparatus or devices for radiation diagnosis} - A61B 6/032: {Transmission computed tomography [CT]} - A61B 6/488: {involving pre-scan acquisition} - A61B 6/5205: {involving processing of raw data to produce diagnostic data} - A61B 6/542: {involving control of exposure} - H05G 1/34: Anode current, heater current or heater voltage of X-ray tube - H05G 1/46: Combined control of different quantities, e.g. exposure time as well as voltage or current - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - H05G: X-RAY TECHNIQUE (investigating or analysing materials by the use of X-rays G01N23/00; apparatus for X-ray photography G03B42/02; X-ray tubes H01J35/00; TV systems having X-ray input H04N5/321) ## Abstract A method is described for controlling a tube current for acquiring at least one X-ray image. The method includes performing a preview acquisition of the region under examination; determining a three-dimensionally modulated X-ray attenuation of the region based upon the preview acquisition; determining initial tube-current profiles based upon the X-ray attenuation; defining a tolerance band for subsequent real-time modification of tube currents, a maximum permitted tube-current profile being determined for which an X-ray tube of the X-ray imaging apparatus does not overheat; determining an expected value and a maximum value of a potential patient dose based upon the initial tube-current profiles and the tolerance band; measuring an actual X-ray attenuation during acquisition of the at least one X-ray image; determining adjusted tube-current profiles based upon the actual X-ray attenuation and the initial tube-current profiles; and adjusting the tube current in accordance with the adjusted tube-current profiles determined. ## Claims ### Claim 1 A method for controlling a tube current for acquiring at least one X-ray image of a region under examination of a subject under examination using an X-ray imaging apparatus, comprising: performing a preview acquisition of the region under examination of the subject under examination; determining a three-dimensionally modulated X-ray attenuation of the region under examination based upon the preview acquisition; determining initial tube-current profiles based upon the three-dimensionally modulated X-ray attenuation determined; defining a tolerance band for subsequent real-time modification of tube currents, wherein, based upon initial tube-current profiles, a maximum permitted tube-current profile is determined for which an X-ray tube of the X-ray imaging apparatus does not overheat; determining an expected value and a maximum value of a potential patient dose based upon the initial tube-current profiles and the tolerance band defined; measuring an actual X-ray attenuation during acquisition of the at least one X-ray image; determining adjusted tube-current profiles based upon the actual X-ray attenuation and the initial tube-current profiles; and adjusting the tube current in accordance with the adjusted tube-current profiles determined. ### Claim 2 (depends on 1) The method of claim 1, wherein the preview acquisition includes a topogram of the region under examination of the subject under examination. ### Claim 3 (depends on 1) The method of claim 1, wherein the preview acquisition includes an optical image acquisition of the region under examination of the subject under examination. ### Claim 4 (depends on 1) The method of claim 1, wherein the determining of the three-dimensionally modulated X-ray attenuation includes determining X-ray attenuation vectors. ### Claim 5 (depends on 4) The method of claim 4, wherein the X-ray attenuation vectors in an anterior/posterior direction and in a lateral direction are determined by way of the preview acquisition. ### Claim 6 (depends on 5) The method of claim 5, wherein the initial tube-current profiles are determined based upon the determined X-ray attenuation in the anterior/posterior direction and in the lateral direction. ### Claim 7 (depends on 5) The method of claim 5, wherein the actual X-ray attenuation is measured in the anterior/posterior direction and in the lateral direction. ### Claim 8 (depends on 1) The method of claim 1, wherein a maximum permitted increase in the patient dose, by way of a configurable parameter, is displayed to the operator during the X-ray image acquisition. ### Claim 9 (depends on 1) The method of claim 1, wherein the X-ray attenuation is determined by division of a logarithm of the attenuation data by a linear absorption coefficient of water. ### Claim 10 (depends on 1) The method of claim 1, wherein the adjustment is performed based upon a function for adjusting the initially planned tube currents including an exponential function of a product of the absorption coefficient of water and a difference between the actual patient attenuation and the X-ray attenuation vectors. ### Claim 11 A tube-current controller for acquiring at least one X-ray image of a region under examination of a subject under examination, comprising: a controller configured to control an X-ray radiation source for acquisition of the at least one X-ray image, and capture raw X-ray data from an X-ray radiation detector; a preview acquisition controller to control a preview acquisition of the region under examination of the subject under examination; an X-ray attenuation estimation unit to estimate a three-dimensionally modulated X-ray attenuation based upon the preview acquisition; a profile definition unit to determine initial tube-current profiles based upon the X-ray attenuation estimated; a band definition unit to define a tolerance band for real-time modification of tube currents, wherein, based upon the initial tube-current profiles, a maximum permitted tube-current profile is determined for which the X-ray tube does not overheat; a dose determination unit to determine an expected value for a potential patient dose based upon the initial tube-current profiles, and a maximum value of a potential patient dose based upon the defined tolerance band; an X-ray attenuation determination unit to determine an actual X-ray attenuation during acquisition of the at least one X-ray image based upon raw X-ray data acquired; and an adjustment unit to determine adjusted tube-current profiles based upon the actual X-ray attenuation and initially planned tube-current profiles, wherein the controller is further configured to adjust the tube current of the X-ray source in accordance with the adjusted tube-current profiles determined. ### Claim 12 (depends on 11) An x-ray imaging apparatus, comprising: an X-ray radiation source including an X-ray tube; an X-ray radiation detector; and the tube-current controller of claim 11. ### Claim 13 (depends on 12) A computed tomography system comprising the X-ray imaging apparatus of claim 12. ### Claim 14 (depends on 1) A non-transitory computer program product storing a computer program, directly loadable into a storage device of an X-ray imaging apparatus, including program segments to perform the method of claim 1 when the computer program is executed in the X-ray imaging apparatus. ### Claim 15 (depends on 1) A non-transitory computer-readable medium, storing program segments, readable and executable by a processor to perform the method of claim 1 when the program segments are executed by the processor. ### Claim 16 (depends on 2) The method of claim 2, wherein the preview acquisition includes an optical image acquisition of the region under examination of the subject under examination. ### Claim 17 (depends on 2) The method of claim 2, wherein the determining of the three-dimensionally modulated X-ray attenuation includes determining X-ray attenuation vectors. ### Claim 18 (depends on 17) The method of claim 17, wherein the X-ray attenuation vectors in an anterior/posterior direction and in a lateral direction are determined by way of the preview acquisition. ### Claim 19 (depends on 2) A non-transitory computer program product storing a computer program, directly loadable into a storage device of an X-ray imaging apparatus, including program segments to perform the method of claim 2 when the computer program is executed in the X-ray imaging apparatus. ### Claim 20 (depends on 2) A non-transitory computer-readable medium, storing program segments, readable and executable by a processor to perform the method of claim 2 when the program segments are executed by the processor.