# US 12,004,284 B2 · Methods and systems for x-ray imaging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,004,284 B2 - Document ID: US12004284B2 - Status: Granted - Kind: B2 - Application number: 17/451,789 - Filed: 2021-10-21 - Published: 2023-04-27 - Granted: 2024-06-04 - Earliest claimed: 2021-10-21 - Assignees: GE Precision Healthcare LLC - Applicants: GE Precision Healthcare LLC - Inventors: James Z. Liu; Russell Dibb; Naveen S. Chandra - Web page: https://patentgrep.com/patent/US12004284B2 ## CPC - A61B 6/542: {involving control of exposure} - H05G 1/04: Mounting the X-ray tube within a closed housing - A61B 6/405: {Source units specially adapted to modify characteristics of the beam during the data acquisition process (A61B6/4021, A61B6/4035 take precedence)} - A61B 6/4085: {Cone-beams} - A61B 6/4441: {the rigid structure being a C-arm or U-arm} - A61B 6/488: {involving pre-scan acquisition} - H05G 1/265: {Measurements of current, voltage or power} - H05G 1/34: Anode current, heater current or heater voltage of X-ray tube - A61B 6/4405: {the apparatus being movable or portable, e.g. handheld or mounted on a trolley} - A61B 6/54: {Control of apparatus or devices for radiation diagnosis} - A61B 6/56: {Details of data transmission or power supply, e.g. use of slip rings} - H01J 35/16: Vessels; Containers; Shields associated therewith - 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) - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract Various methods and systems are provided for medical imaging systems. In one example, an imaging system comprises: a C-shaped gantry; an x-ray tube coupled to a first end of the C-shaped gantry; an x-ray detector coupled to a second end of the C-shaped gantry, opposite to the x-ray tube; and a controller with computer readable instructions stored on non-transitory memory that when executed, cause the controller to: identify a reference image; determine a target electrical current based on the reference image; determine a corrected electrical current based on the target electrical current; and transition an electrical current provided to the x-ray tube to the target electrical current by commanding the electrical current to the corrected electrical current while maintaining a constant voltage provided to the x-ray tube. ## Claims ### Claim 1 An imaging system, comprising: a C-shaped gantry; an x-ray tube coupled to a first end of the C-shaped gantry; an x-ray detector coupled to a second end of the C-shaped gantry, opposite to the x-ray tube; and a controller with computer readable instructions stored on non-transitory memory that when executed, cause the controller to: identify a reference image; determine a target electrical current based on the reference image; determine a corrected electrical current based on the target electrical current; and transition an electrical current provided to the x-ray tube to the target electrical current by commanding the electrical current to the corrected electrical current while maintaining a constant voltage provided to the x-ray tube. ### Claim 2 (depends on 1) The imaging system of claim 1, wherein determining the corrected electrical current based on the target electrical current includes calculating the corrected electrical current as a function of the target electrical current, where the corrected electrical current is less than both of the target electrical current and the electrical current provided to the x-ray tube or greater than both of the target electrical current and the electrical current provided to the x-ray tube. ### Claim 3 (depends on 1) The imaging system of claim 1, further comprising computer readable instructions stored on the non-transitory memory that when executed, cause the controller to: acquire a series of images in a single scan of a subject while rotating the C-shaped gantry around the subject; and for each image in the series of images, as each image is acquired: identify a most recently-acquired image in the series of images as an updated reference image; determine an updated target electrical current based on the updated reference image; determine an updated corrected electrical current based on the updated target electrical current; and transition the electrical current provided to the x-ray tube to the updated target electrical current by commanding the electrical current to the updated corrected electrical current while maintaining the constant voltage provided to the x-ray tube. ### Claim 4 (depends on 1) The imaging system of claim 1, wherein the constant voltage is based on the reference image and is maintained for each image acquired throughout an entire duration of a scan performed by the imaging system. ### Claim 5 (depends on 1) The imaging system of claim 1, further comprising computer readable instructions stored on the non-transitory memory that when executed, cause the controller to: acquire an image of a subject by: first, performing the identifying of the reference image; then performing the determining of the target electrical current based on the reference image; then performing the determining of the corrected electrical current based on the target electrical current; then performing the transitioning the electrical current provided to the x-ray tube to the target electrical current by commanding the electrical current to the corrected electrical current while maintaining the constant voltage provided to the x-ray tube; then while maintaining the constant voltage provided to the x-ray tube and maintaining the electrical current provided to the x-ray tube at the target electrical current, emitting x-ray radiation from the x-ray tube and receiving attenuated x-ray radiation at the x-ray detector. ### Claim 6 (depends on 1) The imaging system of claim 1, wherein the corrected electrical current is a function of the target electrical current, the electrical current provided to the x-ray tube, and a commanded duration between acquisition of sequential images of a subject; and the target electrical current is a function of a video level indicator of the reference image and an initial electrical current provided to the x-ray tube during acquisition of the reference image. ### Claim 7 (depends on 1) The imaging system of claim 1, wherein the corrected electrical current is defined by: mA c = mA ⁡ ( t ) - mA 0 ⁢ e - t / T m ⁢ A 1 - e - t / T m ⁢ A . wherein mAc is the corrected electrical current, mA(t) is the target electrical current at time t, mA0 is an initial electrical current, and TmA is a time constant of the x-ray tube. ### Claim 8 (depends on 1) The imaging system of claim 1, wherein the target electrical current is defined by: mA(t)=mA0+Σn=1N an(mA0, δmA)×tn wherein mA(t) is the target electrical current at time t, and an(mA0, δmA) is a coefficient based on an initial electrical current mA0 and a difference δmA between the initial electrical current and the corrected electrical current at time t=0. ### Claim 9 (depends on 1) The imaging system of claim 1, wherein the target electrical current is defined by: mA ⁡ ( k + 1 ) = ( VLI T VLI ⁡ ( k ) ) 2 × mA ⁡ ( k ) wherein mA(k+1) is the target electrical current, VLIT is a target video level indicator, VLI(k) is a video level indicator of the reference image, and mA(k) is an initial electrical current. ### Claim 10 A method for a C-arm imaging system, comprising: determining an initial electrical current provided to an x-ray tube during acquisition of a reference image; determining a video level of a region of interact within the reference image; determining a target electrical current to be provided to the x-ray tube based on the video level; determining a corrected electrical current based on the target electrical current; and adjusting an actual electrical current provided to the x-ray tube from the initial electrical current to the target electrical current by commanding the actual electrical current to the corrected electrical current. ### Claim 11 (depends on 10) The method of claim 10, wherein an absolute value of a difference between the initial electrical current and the target electrical current is less than an absolute value of a difference between the initial electrical current and the corrected electrical current. ### Claim 12 (depends on 10) The method of claim 10, wherein the video level of the region of interact is proportional to the initial electrical current. ### Claim 13 (depends on 10) The method of claim 10, wherein the video level is defined by: VLI(k)=KVLI√{square root over (mA(k))} wherein VLI(k) is the video level of the region of interact, mA(k) is the initial electrical current, and KVLI is a proportionality coefficient. ### Claim 14 (depends on 10) The method of claim 10, further comprising: maintaining a scan voltage at a constant value throughout an entire duration of the adjustment of the actual electrical current from the initial electrical current to the target electrical current. ### Claim 15 (depends on 10) The method of claim 10, further comprising: determining an image acquisition rate of the C-arm imaging system based on a rotational speed of a C-arm of the C-arm imaging system; and determining a transition duration of the actual electrical current from the initial electrical current to the target electrical current based on the image acquisition rate. ### Claim 16 (depends on 15) The method of claim 15, wherein the corrected electrical current is based on the transition duration.