Microbubble Cavitation Localization via Time-Domain Signal Correlation
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Solution Overview
Problem
Current ultrasound systems lack effective methods for detecting and monitoring microbubble cavitation during ultrasound procedures, which can lead to undesired bio-effects such as tissue damage and hemorrhage due to the inability to accurately adjust therapeutic plans.
Innovation Solution
A system and method for detecting microbubble cavitation using a library of reference signals acquired through physical models or echo signals, allowing for the identification of cavitation types and locations by comparing received echo signals with stored reference signals in the time domain, reducing signal processing complexity and time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ultrasound systems are used without cavitation detection, then the ultrasound procedure can be performed, but microbubble cavitation cannot be detected leading to undesired bio-effects such as tissue damage and hemorrhage
Solution Approach 1:
The patent introduces an intermediary detection system that uses a separate transducer array to detect acoustic signals emitted during microbubble cavitation. This intermediary detection mechanism allows for indirect observation of cavitation events without directly interfering with the primary therapeutic ultrasound beam, enabling safe monitoring of the procedure.
Solution Approach 2:
The patent replaces direct mechanical observation or invasive measurement methods with acoustic signal detection. By listening to the acoustic emissions naturally produced during cavitation events, the system can detect and monitor microbubble activity without mechanical interference, enabling non-invasive safety monitoring.
2Productivity
If high acoustic pressure is applied to induce unstable cavitation for therapeutic effect, then therapeutic bio-effects are achieved, but extensive tissue damage and hemorrhage occur
Solution Approach 1:
The patent implements a feedback mechanism where acoustic signals from microbubble cavitation are continuously detected and analyzed. The system uses this feedback information to monitor cavitation activity in real-time and adjust the acoustic pressure accordingly, preventing excessive cavitation that would cause tissue damage while maintaining therapeutic efficacy.
Solution Approach 2:
The patent enables dynamic adjustment of acoustic pressure based on real-time cavitation detection. The system transitions from static, fixed-pressure ultrasound application to dynamic, adaptive pressure control that responds to actual cavitation events, optimizing the balance between therapeutic effect and tissue safety.
3Use of energy by moving object
If stable cavitation is induced at low acoustic pressure to enhance energy absorption, then tissue heating efficiency is improved, but the ability to induce therapeutic effects is reduced
Solution Approach 1:
The patent enables dynamic modulation of acoustic pressure to transition between stable and unstable cavitation regimes as needed. The system can start with low-pressure stable cavitation for efficient energy absorption and heating, then increase pressure to induce unstable cavitation when therapeutic mechanical effects are required, optimizing both energy efficiency and therapeutic outcome.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise detection and localization of microbubble cavitation, allowing for real-time adjustment of ultrasound treatment plans to minimize tissue damage and enhance therapeutic efficacy.
Implementation Method 1
a piezoceramic transducer is placed externally to the patient, but in close proximity to the tissue to be ablated. The transducer converts an electronic drive signal into mechanical vibrations, resulting in the emission of acoustic waves.
Implementation Method 2
small gas bubbles (or 'microbubbles') may be generated in the liquid fraction of the target tissue, e.g., due to the stress resulting from negative pressure produced by the propagating ultrasonic waves and/or due to rupture of the heated liquid and its accumulation of gas/vapor.
Implementation Method 3
the microbubbles may collapse (this mechanism is called 'cavitation') and cause various thermal effects in the target and/or its surrounding tissue. At a low acoustic pressure, stable cavitation of microbubbles may be induced to enhance energy absorption at the ultrasound focal region.
Implementation Method 4
a single transducer may be formed of a plurality of individually driven transducer elements whose phases can each be controlled independently. Such a 'phased-array' transducer facilitates steering the focal zone to different locations by adjusting the relative phases among the transducers.
Implementation Method 5
The transducer may be geometrically shaped and positioned along with other such transducers so that the ultrasound energy they emit collectively forms a focused beam at a 'focal zone' corresponding to (or within) the target tissue region.
Data Source
AI summary
Various approaches for detecting microbubble cavitation resulting from ultrasound waves transmitted from an ultrasound transducer include associating at least one time-domain reference signal with microbubble cavitation; causing the transducer to transmit one or more ultrasound pulse; acquiring, in the time domain, an echo signal from microbubbles in response to the transmitted ultrasound pulse(s); correlating at least a portion of the echo signal to at least a corresponding portion of the time-domain reference signal based on similarity therebetween; and detecting the microbubble cavitation based on the corresponding portion of the reference signal.