Piezoelectric Flow Sensor for Microwave Ablation Probe Cooling
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Solution Overview
Problem
Microwave ablation systems face challenges in monitoring correct system operation and preventing overheating due to potential defects in antenna assemblies and interruptions in coolant flow, which can lead to rapid failures and temperature control issues.
Innovation Solution
A microwave ablation system that includes a piezoelectric transducer to detect fluid flow through the coolant path, generating a signal used by a controller to adjust the energy source output, ensuring proper coolant circulation and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microwave energy is delivered to tissue to achieve ablation, then therapeutic effect is improved, but risk of overheating and tissue damage increases
Solution Approach 1:
The system continuously monitors fluid flow through the coolant path using a flow sensor and provides real-time feedback to the controller. The controller adjusts microwave energy delivery based on this feedback, reducing or stopping energy delivery when flow is insufficient to prevent overheating, thus resolving the contradiction between achieving therapeutic effect and preventing harmful overheating
Solution Approach 2:
A fluid coolant is introduced as an intermediary substance to absorb excess heat from the antenna assembly and surrounding tissue. The coolant circulates through a dedicated path, acting as a thermal mediator that protects the antenna and adjacent healthy tissue from overheating while allowing higher microwave energy delivery for effective ablation
2Object-affected harmful factors
If fluid flow monitoring is added to prevent overheating, then safety is improved, but device complexity increases
Solution Approach 1:
The system uses the existing coolant fluid itself to generate the monitoring signal. The flow sensor detects properties of the coolant flow (such as pressure or flow rate), and the coolant's own physical properties provide the feedback mechanism. This self-service approach enables monitoring without requiring complex external sensing systems, thus improving safety while minimizing the increase in device complexity
3Temperature
If continuous monitoring and adjustment of energy output is implemented, then temperature control precision is improved, but energy efficiency decreases
Solution Approach 1:
The system implements periodic monitoring of fluid flow and periodic adjustment of energy output rather than continuous modulation. The controller monitors flow conditions and adjusts microwave energy delivery in controlled intervals, maintaining precise temperature control through periodic feedback cycles. This approach achieves the required temperature precision while minimizing unnecessary energy consumption associated with continuous adjustment mechanisms
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
The system effectively monitors fluid flow and adjusts energy output to prevent damage to the antenna and ensure safe operation, maintaining precise temperature control and preventing overheating.
Implementation Method 1
a piezoelectric transducer operably coupled to the fluid path to detect a force of fluid flow through the fluid path. The piezoelectric transducer is configured to generate a signal based on the detected force of fluid through the fluid path.
Implementation Method 2
The microwave energy is able to non-invasively penetrate the skin to reach the underlying tissue. Such microwave ablation procedures, e.g., such as those performed for menorrhagia, are typically done to ablate and coagulate the targeted tissue to denature or kill the tissue.
Data Source
AI summary
A microwave ablation system includes an antenna assembly configured to deliver microwave energy from an energy source to tissue and a coolant source operably coupled to the energy source and configured to selectively provide fluid to the antenna assembly via a fluid path. The system also includes a controller operably coupled to the energy source and a piezoelectric transducer operably coupled to the fluid path to detect a force of fluid flow through the fluid path. The piezoelectric transducer is configured to generate a signal based on the detected force of fluid through the fluid path. The controller is configured to control the energy source output based on the generated signal.