# US 11,076,915 B2 · System and method for monitoring a microwave tissue ablation process > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,076,915 B2 - Document ID: US11076915B2 - Status: Granted - Kind: B2 - Application number: 15/597,855 - Filed: 2017-05-17 - Published: 2018-01-11 - Granted: 2021-08-03 - Earliest claimed: 2016-07-11 - Assignees: Gyrus Medical Limited - Applicants: Gyrus Medical Limited - Inventors: David Nicholas Williams; Tudor Thomas - Web page: https://patentgrep.com/patent/US11076915B2 ## CPC - A61B 18/1815: {using microwaves} - A61B 2018/00577: {Ablation} - A61B 2018/00642: {with feedback, i.e. closed loop control} - A61B 2018/00678: {upper} - A61B 2018/00708: {switching the power on or off} - A61B 2018/00714: {Temperature} - A61B 2018/00797: {measured by multiple temperature sensors} - A61B 2018/00821: {measured by a thermocouple} - A61B 2018/1823: {Generators therefor} - A61B 2018/1838: {Dipole antennas} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A method and system for monitoring a microwave tissue ablation process, particularly the determination of an ablation size estimate during microwave ablation of such tissue. The method includes applying a correction value to the determined temperature value, so as to provide a corrected temperature value. ## Claims ### Claim 1 A method of monitoring a microwave tissue ablation process, the method comprising: providing a power source operable to provide a controlled microwave energy output; providing a microwave probe having a body and an antenna extending through the body and operable to deliver the microwave energy from the power source out of the microwave probe; providing a thermocouple on an outer surface of the body of the microwave probe, the thermocouple being separated from the body by a layer of thermally insulating material, the thermocouple being operable to generate an output voltage in dependence upon a temperature experienced by the thermocouple; supplying the controlled microwave energy output from the power source to the antenna, thereby causing the microwave energy to radiate from the antenna to form an ablation zone; detecting an output voltage generated by the thermocouple in response to a temperature experienced by the thermocouple; determining a temperature value relating to the detected output voltage; applying a predetermined correction value to the determined temperature value, so as to provide a corrected temperature value, the predetermined correction value relating to a total amount of the microwave energy supplied to the antenna from the start of the ablation process to the determination of the temperature value; and wherein the predetermined correction value also relates to a temperature of a coolant fluid used inside the body of the microwave probe. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the predetermined correction value also relates to a location of the thermocouple on the body of the microwave probe. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the predetermined correction value also relates to time of application of the microwave energy. ### Claim 4 The method as claimed in claiml, wherein the corrected temperature value is a predetermined multiple of the determined temperature value. ### Claim 5 (depends on 1) The method as claimed in claim 1, further comprising determining an ablation estimate from the corrected temperature value, the ablation estimate relating to a volume of tissue ablated due to radiation of the microwave energy from the antenna. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the thermocouple comprises a plurality of thermocouples on the body of the microwave probe, the plurality of thermocouples being located at respective locations on the body, and wherein a respective corrected temperature value is provided for each of the plurality of thermocouples in dependence upon respective determined temperature values and predetermined correction values for each of the pluralilty ofthermocouples. ### Claim 7 (depends on 1) The method of controlling the microwave probe during the microwave ablation of the tissue, the method comprising the method of monitoring the microwave tissue ablation process as claimed in claim 1, and further comprising controlling the microwave energy supplied from the power source to the antenna such that the corrected temperature value substantially reaches a predetermined target value. ### Claim 8 (depends on 7) The method as claimed in claim 7, further comprising terminating the supply of the microwave energy from the power source when the corrected temperature value substantially reaches the predetermined target value. ### Claim 9 A microwave ablation apparatus comprising: a power source operable to provide a controlled microwave energy output; a microwave probe having a body and an antenna extending through the body and operable to deliver the microwave energy from the power source out of the microwave probe; a thermocouple on an outer surface of the body of the microwave probe, the thermocouple being separated from the body by a layer of thermally insulating material, the thermocouple being operable to generate an output voltage in dependence upon a temperature experienced by the thermocouple; a detector operable to detect an output voltage generated by the thermocouple in response to the temperature experienced by the thermocouple; a calculation unit operable to determine a temperature value relating to the detected output voltage; a correction unit operable to apply a predetermined correction value to the determined temperature value, and to provide a corrected temperature value, the predetermined correction value relating to a total amount of energy supplied to the antenna from a start of such ablation to the determination of the temperature value; a controller operable to control the microwave energy supplied to the antenna from the power source such that the corrected temperature value reaches a predetermined target value; and wherein the predetermined correction value also relates to a temperature of a coolant fluid used inside the body of the microwave probe. ### Claim 10 (depends on 9) The apparatus as claimed in claim 9, wherein the predetermined correction value also relates to a location of the thermocouple on the body of the microwave probe. ### Claim 11 (depends on 9) The apparatus as claimed in claim 9, wherein the predetermined correction value also relates to time of application of the microwave energy. ### Claim 12 (depends on 9) The apparatus as claimed in claim 9, wherein the corrected temperature value is a predetermined multiple of the determined temperature value. ### Claim 13 The apparatus as claimed in claimed 9, wherein the predetermined correction value is chosen from a range of predetermined correction values in dependence upon power level and application time of the microwave energy. ### Claim 14 (depends on 9) The apparatus as claimed in claim 9, wherein the thermocouple comprises a plurality of thermocouples on the body of the microwave probe, the plurality of thermocouples being located at respective locations on the body, and wherein the correction unit is operable to provide respective corrected temperature values for each of the plurality of thermocouples in dependence upon respective determined temperature values and predetermined correction values for each of the plurality of thermocouples, and wherein the controller is operable to control microwave energy supplied to the antenna in dependence upon the corrected temperature values for the plurality of thermocouples. ### Claim 15 (depends on 9) The apparatus as claimed in claim 9, wherein the controller is operable to terminate supply of the microwave energy from the power source when the corrected temperature value substantially reaches the predetermined target value.