RF Thermal Ablation Coil Parasitic Capacitance Monitoring
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Solution Overview
Problem
Current radio frequency thermal ablation technologies face challenges in accurately controlling the treatment process due to insufficient temperature sensing, leading to potential organ wall adherence and carbonization, as they rely solely on temperature and time adjustments without comprehensive monitoring of organ wall distance and fluid coagulation.
Innovation Solution
A radio frequency thermal ablation system that utilizes parasitic capacitance between winding turns to monitor organ shrinkage and adjust power output, enhancing sensitivity through inductive insulated heating coils and real-time impedance monitoring, allowing for precise control of treatment parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature feedback control is used to control heating time and temperature, then the heating process can be controlled, but the treatment accuracy is insufficient leading to organ wall adherence and carbonization
Solution Approach 1:
The patent implements a dual feedback control system: (1) temperature feedback through thermocouples that monitor tissue temperature and adjust RF power accordingly, and (2) impedance feedback through parasitic capacitance measurement that detects organ wall distance and fluid coagulation state. This combined feedback approach enables real-time adjustment of heating parameters to prevent both under-treatment and overheating, resolving the contradiction between treatment accuracy and harmful effects
Solution Approach 2:
The patent replaces direct mechanical contact sensing with electromagnetic field-based sensing. By measuring changes in parasitic capacitance between the heating coil and surrounding tissues, the system non-invasively detects organ wall distance and fluid coagulation without requiring physical contact or additional mechanical sensors in the ablation zone, thereby improving measurement precision while avoiding interference with the thermal field
2Measurement precision
If dense temperature sensing points are arranged in the entire ablation area, then treatment accuracy can be improved, but engineering feasibility and cost constraints cannot be met
Solution Approach 1:
The patent makes the RF heating coil serve multiple functions: it simultaneously acts as the heating element for thermal ablation and as the sensing element for detecting organ wall distance and fluid coagulation through parasitic capacitance measurement. This eliminates the need for separate sensor arrays in the ablation zone, reducing device complexity while maintaining comprehensive monitoring capability through the existing electromagnetic field infrastructure
Solution Approach 2:
The system uses its own electromagnetic field and heating coil structure to perform sensing functions. The parasitic capacitance inherent in the coil-tissue interface is transformed into a useful sensing mechanism, allowing the system to self-monitor treatment progress without requiring external or additional sensing components, thereby avoiding the complexity and cost of dense temperature sensor arrays
3Device complexity
If simple temperature feedback control is used, then device complexity is reduced, but the ability to detect organ wall distance and fluid coagulation is lost
Solution Approach 1:
The patent substitutes mechanical or contact-based sensing with electromagnetic field-based sensing using parasitic capacitance measurement. By monitoring changes in the electrical characteristics of the RF circuit caused by tissue properties and geometry, the system obtains information about organ wall distance and fluid coagulation state without adding complex mechanical sensor systems, thus maintaining relatively simple device architecture while gaining critical diagnostic information
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
This system enables safer and more accurate thermal ablation by effectively controlling the distance of the organ wall from the catheter and degree of fluid coagulation, reducing the risk of overheating and improving treatment outcomes.
Implementation Method 1
an inductive insulated heating coil, wherein the inductance is designed to configure the operating frequency when detecting the parasitic capacitance between winding turns
Implementation Method 2
monitor the change of WPC (winding parasitic capacitance) between the insulation heating windings caused by the tubular organ wall approaching the insulated heating windings and/or the coagulation of body fluid
Implementation Method 3
radio frequency energy is not directly applied onto the human body, but is converted into heat energy inside the device
Data Source
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AI summary
This application relates to radio frequency thermal ablation system and control method therefor. The radio frequency thermal ablation system comprises: a thermal ablation catheter that comprises an inductive insulated heating coil, wherein the inductance is designed to configure the operating frequency when detecting the parasitic capacitance between winding turns, and enhance the detecting sensitivity; a radio frequency generator that supplies radio frequency power to heat said heating coil; a WPC (winding parasitic capacitance) detecting device that monitors the change of the WPC between the insulation heating windings caused by the tubular organ wall approaching the insulated heating windings and/or the coagulation of body fluid during the heating process; a control device that controls the amount of radio frequency power output from said radio frequency generator to said heating coil according to the change of said WPC between the windings detected by said WPC detecting device.