# US 11,304,621 B2 · Radiation-free position calibration of a fluoroscope > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,304,621 B2 - Document ID: US11304621B2 - Status: Granted - Kind: B2 - Application number: 13/937,508 - Filed: 2013-07-09 - Published: 2015-01-15 - Granted: 2022-04-19 - Earliest claimed: 2013-07-09 - Assignees: Biosense Webster (Israel) Ltd. - Applicants: Biosense Webster (Israel), Ltd. - Inventors: Asaf Merschon; Eliahu Zino; Ofer Eliahu Klemm; Roy Urman; Ronen Krupnik; Liron Shmuel Mizrahi - Web page: https://patentgrep.com/patent/US11304621B2 ## CPC - A61B 5/061: {Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body (A61B1/00158 takes precedence)} - A61B 5/0071: {by measuring fluorescence emission} - A61B 6/547: {involving tracking of position of the device or parts of the device} - A61B 2034/2051: {Electromagnetic tracking systems} - A61B 2090/364: {Correlation of different images or relation of image positions in respect to the body} - A61B 2090/376: {using X-rays, e.g. fluoroscopy} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A method includes registering a fluoroscopic imaging system and a position tracking system to a common frame of reference. A region of interest is marked in a patient body by the position tracking system. Using the common frame of reference, a field of view of the fluoroscopic imaging system is set such that the region of interest appears in the field of view. ## Claims ### Claim 1 A method for calibrating a position of a fluoroscopic imaging system having a field of view so that a region of interest of a patient body is at a center of the field of view, said method comprising: (i) registering the fluoroscopic imaging system to a common frame of reference using a fluoroscopic image and position data by imaging using the fluoroscopic imaging system one or more objects having known coordinates in a first coordinate system of a position tracking system, and registering the first coordinate system of the position tracking system with a second coordinate system of the fluoroscopic imaging system: (ii) marking a region of interest in a patient body comprising measuring using respective positions of one or more sensors of the position tracking system that are positioned at known locations relative to the region of interest; (iii) setting the field of view of the fluoroscopic imaging system such that the region of interest appears at a center of the field of view wherein setting the field of view includes subsequent repositioning of the patient body without applying any fluoroscopic radiation to the patient relative to the fluoroscopic imaging system in accord with instructions provided by a processor when the region of interest did not previously appear centered in the field of view of the fluoroscopic imaging system; (iv) calculating a median location of a plurality of intra-body probes within the body of the patient, and estimating a location of the region of interest based on the median location. ### Claim 2 (depends on 1) The method according to claim 1, wherein setting the field of view comprises positioning the fluoroscopic imaging system relative to the patient, without irradiating the patient body with the fluoroscopic imaging system. ### Claim 3 (depends on 1) The method according to claim 1, wherein measuring the positions comprises locating one or more skin patch sensors of the position tracking system that are applied on a surface of the patient body. ### Claim 4 (depends on 1) The method according to claim 1, wherein measuring the region of interest comprises marking a fixed location in a three dimensional map of the region of interest in the patient body produced by the position tracking system. ### Claim 5 (depends on 1) The method according to claim 1, wherein setting the field of view comprises repositioning the patient body relative to the fluoroscopic imaging system so as to provide a largest overlap between the region of interest and the field of view. ### Claim 6 (depends on 1) The method according to claim 1, wherein the one or more objects are one or more magnetic field generators positioned near the patient body. ### Claim 7 A fluoroscopic position calibration system for calibrating a position of a fluoroscopic imaging system having a field of view so that a region of interest of a patient body is at a center of the field of view, said apparatus comprising: an interface for communicating with a fluoroscopic imaging system and a position tracking system; and a processor which is configured to register the fluoroscopic imaging system and a position tracking system to common frame of reference using a fluoroscopic image and position data to a common frame of reference by imaging using the fluoroscopic imaging system one or more objects having known coordinates in a first coordinate system of the position tracking system, and registering the first coordinate system of the position tracking system with a second coordinate system of the fluoroscopic imaging system; to mark a region of interest in a patient body comprising measuring using respective positions of one or more sensors of the position tracking system that are positioned at known locations relative to the region of interest, and to set the field of view of the fluoroscopic imaging system such that the region of interest appears at a center of the field of view wherein to set the field of view includes subsequent repositioning of the patient body without applying any fluoroscopic radiation to the patient relative to the fluoroscopic imaging system in accord with instructions provided by the processor when the region of interest did not previously appear centered in the field of view of fluoroscopic imaging system; wherein the processor is further configured to calculate the median location of a plurality of intra-body probes within the body of the patient, and to estimate a location of the region of interest based on the median location. ### Claim 8 (depends on 7) The apparatus according to claim 7, wherein the processor is configured to set the field of view without irradiating the patient with the fluoroscopic imaging system. ### Claim 9 (depends on 7) The apparatus according to claim 7, wherein the processor is configured to measure the positions by locating one or more skin patch sensors of the position tracking system that are applied on a surface of the patient body. ### Claim 10 (depends on 7) The apparatus according to claim 7, wherein the processor is configured to identify the region of interest as a fixed location in a three dimensional map of the region of interest in the patient's body produced by the position tracking system. ### Claim 11 (depends on 7) The apparatus according to claim 7, wherein the processor is configured to set the field of view by repositioning the patient body relative to the fluoroscopic imaging system so as to provide a largest overlap between the region of interest and the field of view. ### Claim 12 (depends on 7) The apparatus according to claim 7, wherein the one or more objects are one or more magnetic field generators positioned near the patient body. ### Claim 13 A system comprising: a position tracking system; a fluoroscopic tracking system; and a fluoroscopic position calibration system for calibrating a position of a fluoroscopic imaging system having a field of view so that a region of interest of a patient body is at a center of the field of view, said apparatus comprising: an interface for communicating with a fluoroscopic imaging system and a position tracking system; and a processor which is configured to register the fluoroscopic imaging system and a position tracking system to common frame of reference using a fluoroscopic image and position data to a common frame of reference by imaging using the fluoroscopic imaging system one or more objects having known coordinates in a first coordinate system of the position tracking system, and registering the first coordinate system of the position tracking system with a second coordinate system of the fluoroscopic imaging system to mark a region of interest in a patient body comprising measuring using respective positions of one or more sensors of the position tracking system that are positioned at known locations relative to the region of interest, and to set the field of view of the fluoroscopic imaging system such that the region of interest appears at a center of the field of view wherein to set the field of view includes subsequent repositioning of the patient body without applying any fluoroscopic radiation to the patient relative to the fluoroscopic imaging system in accord with instructions provided by the processor when the region of interest did not previously appear centered in the field of view of fluoroscopic imaging system; wherein the processor is further configured to calculate the median location of a plurality of intra-body probes within the body of the patient, and to estimate a location of the region of interest based on the median location. ### Claim 14 (depends on 13) The system according to claim 13, wherein the one or more objects are one or more magnetic field generators positioned near the patient body.