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US 2021/0059752 A1Published application
Methods for photoacoustic temperature measurement
AssigneeBin Rao
InventorBIN RAO
Life of this patent
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Abstract
TEMPERATURE MEASUREMENTS ARE CRITICAL TO VARIOUS ENERGY BASED THERAPEUTIC SYSTEMS, INCLUDING LASER, LIGHT, ELECTROMAGNETIC WAVE, AND HIGH INTENSITY FOCUSED ULTRASOUND BASED THERAPEUTIC SYSTEMS. THIS INVENTION DISCLOSES TECHNIQUES, APPARATUS AND METHODS FOR TEMPERATURE MEASUREMENTS OF SURGICAL TARGETS DURING VARIOUS THERAPEUTIC INTERVENTIONS WITH PHOTOACOUSTIC METHODS, ESPECIALLY WHEN DYNAMIC TEMPERATURE PULSES ARE GENERATED BY SELECTIVE PHOTOTHERMOLYSIS.
Claims3
A photoacoustic temperature measurement method comprising:
- calibrating a relative logarithm function of Grüneisen parameter of a media surrounding said target;
- determining an ambient temperature of said target;
- exciting a photoacoustic wave from said target with a laser pulse of constant pulse energy under said ambient temperature, measuring an amplitude of said photoacoustic wave with an acoustic detector, and calculating a logarithm value of said amplitude as a baseline signal;
- applying a temperature changing mechanism and measuring a corrective photoacoustic response if necessary;
- applying said temperature changing mechanism immediately followed by said laser pulse at a desirable delay time, exciting a photoacoustic wave from said target, measuring an amplitude of photoacoustic wave, subtracting said corrective photoacoustic response if necessary, calculating a logarithm value, and getting a relative logarithm value;
- determining the temperature of said target at the desired delay time after application of said temperature changing mechanism based on said ambient temperature, said relative logarithm value and said relative logarithm function of Grüneisen parameter of said media.
3 more elements
A method for calibrating a relative logarithm function of Grüneisen parameter of a media surrounding a target comprising:
- heating said target to a series of temperature points by sending a series of short heating laser pulses with increasing laser pulse energies until the last laser pulse induces photodisruption in tissue and said target reaches 100° C.;
- determining said series of temperature points based on excited photoacoustic waves and the linear relationship between temperature rises and excited photoacoustic waves;
- calibrating photoacoustic responses of said target by sending temperature sensing laser pulses with constant pulse energy immediately after said temperature points are reached and correcting photoacoustic responses induced by short heating laser pulses alone;
- determining said relative logarithm function of Grüneisen parameter of said media surrounding said target.
1 more element
Dependencies are inferred from the claim text.