Ablation Volume Estimation via Thermal Feedback
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Solution Overview
Problem
Current ablation systems using RF electrodes lack effective feedback mechanisms to determine the completeness of tissue ablation procedures, limiting the size of lesion volumes produced and the precision of treatment.
Innovation Solution
A system comprising an electrosurgical energy source, an electrode probe assembly, and a thermal feedback assembly with temperature sensors, connected to a computer that measures energy delivery time, estimates ablation volume size, and calculates growth rate to determine when the ablation procedure is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If multiple electrodes are inserted into tumors in a dispersed fashion to cover the tumor volume with uniform heat, then the ablation volume can be enlarged, but the system lacks feedback mechanisms to determine ablation completeness
Solution Approach 1:
The patent implements a feedback mechanism by measuring temperature at multiple points during ablation and using these measurements to estimate the ablation volume and determine when ablation is complete. Temperature sensors monitor the thermal field, and the system calculates ablation volume based on temperature readings, providing real-time feedback to guide the ablation process and determine when the desired volume has been achieved.
Solution Approach 2:
The patent replaces direct mechanical measurement of ablation volume with a thermal field-based estimation system. Instead of physically measuring the ablated tissue volume, the system uses temperature measurements and thermal conduction models to estimate the ablation volume, substituting mechanical measurement with thermal sensing and computational estimation.
2Temperature
If electrodes are activated simultaneously or sequentially with high frequency energy, then tissue heating occurs to create therapeutic changes, but there is no way to inform the surgeon when ablation is complete
Solution Approach 1:
The system provides feedback by continuously monitoring temperature during electrode activation and comparing the measured temperature profile against expected thermal conduction patterns. The computer estimates ablation volume based on temperature readings and notifies the surgeon when the estimated volume indicates complete ablation, providing real-time information about treatment status.
Solution Approach 2:
The patent introduces temperature measurements and computational estimation as intermediaries between the electrode-tissue interaction and the surgeon's decision-making. The system measures temperature, processes the data through thermal conduction models, and provides interpreted information about ablation completeness, serving as an intermediary that translates physical heating into actionable clinical information.
3Duration of action of moving object
If energy is applied to each electrode one at a time in series activation, then the sequence continues at a prescribed frequency for a period of time, but the system cannot determine when the desired ablation volume has been achieved
Solution Approach 1:
The system implements feedback by measuring temperature at multiple points during the series activation sequence and using these measurements to continuously estimate ablation volume. The computer monitors the relationship between energy delivery time, temperature readings, and estimated volume, providing real-time feedback on how close the procedure is to achieving complete ablation.
Solution Approach 2:
The patent changes the approach from fixed-duration energy delivery to parameter-based termination. Instead of applying energy for a predetermined time, the system adjusts the energy delivery duration based on measured temperature and estimated ablation volume, using parameter changes (temperature, volume estimation) to determine when to stop energy application.
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 provides precise monitoring and feedback during ablation procedures, enabling more accurate prediction and control of treatment depth and volume, ensuring complete ablation while minimizing unnecessary energy application.
Implementation Method 1
when the RF electrode is connected to an external source of radiofrequency power, e.g., an electrosurgical generator (device used to generate therapeutic energy such as radiofrequency (RF)), and current is delivered to the RF electrode, heating of tissue occurs near and around the exposed conductive tip portion thereof
Implementation Method 2
The computer may be configured to interpolate one or more temperatures based on boundary conditions and a single measured temperature
Data Source
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AI summary
A system and method for determining completion of an ablation procedure is provided. An electrosurgical generator provides an electrosurgical energy source to an electrode probe assembly. The generator is connected to a thermal feedback assembly that includes at least one temperature sensor assembly. The generator includes a computer configured to (1) measure a time of energy delivered to the target tissue, (2) receive a temperature reading from the thermal feedback assembly, (3) estimate a size of an ablation volume based on the temperature reading, a distance between the electrode probe assembly and each temperature sensor assembly, and the measured time, (4) calculate a growth rate of the ablation volume based on the estimated size. The computer may also determine the ablation procedure is complete when the growth rate is less than or equal to a threshold.