Pulse Modulated RF Tissue Ablation for Lesion Diameter
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Solution Overview
Problem
Current radiofrequency (RF) ablation technologies for treating tumors face limitations in increasing lesion diameter due to heat dispersion and tissue vaporization, which leads to increased tissue impedance and reduced heat diffusion, necessitating longer procedure times.
Innovation Solution
The method involves pulsing radiofrequency energy on and off based on sensed physiological parameters like impedance and temperature to maintain optimal moisture concentration, and amplitude modulating the energy to ensure effective ablation, using a control circuitry system that generates trigger signals for pulsing and amplitude adjustments based on threshold values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If generator output power is increased to increase lesion diameter, then ablation volume increases, but tissue temperature exceeds 100°C causing vaporization and charring which increases tissue impedance and limits further RF deposition
Solution Approach 1:
The patent applies periodic action by delivering RF energy in a pulsed waveform pattern rather than continuous delivery. The generator alternates between active RF delivery phases and pause phases, allowing tissue temperature to reset below vaporization thresholds during pauses. This periodic delivery enables sustained ablation volume expansion without permanent tissue charring or impedance buildup that would limit further treatment.
2Productivity
If RF energy is delivered continuously to maximize ablation volume, then procedure time is reduced, but tissue moisture is depleted leading to increased impedance and limited heat diffusion
Solution Approach 1:
The patent implements continuity of useful action through automated pulse-pause cycles that maintain optimal ablation conditions throughout the procedure. The system continuously monitors tissue impedance and automatically adjusts RF delivery by initiating pause phases when impedance thresholds indicate moisture depletion, then resuming delivery when moisture levels recover. This automated continuous management ensures sustained high-level ablation without manual intervention while preventing permanent moisture loss.
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 approach maximizes the delivery of ablation energy by maintaining energy output during tissue moisture changes, reducing procedure time and minimizing tissue charring, thereby enhancing the efficiency of RF ablation.
Implementation Method 1
the energy that is conveyed from the electrode(s) translates into ion agitation, which is converted into heat and induces cellular death via coagulation necrosis
Implementation Method 2
sensing a physiological parameter (e.g., impedance and/or temperature) indicative of a change in moisture concentration of the tissue
Data Source
AI summary
Tissue ablation systems and methods are provided. Ablation energy (e.g., radio frequency energy) is delivered to the tissue and a physiological parameter (e.g., impedance and/or temperature) indicative of a change in moisture concentration of the tissue is sensed. The ablation energy is alternately pulsed on and off to generate an energy pulse train, with the ablation energy being pulsed on if the sensed physiological parameter crosses a threshold value indicative of an increase in the moisture concentration, and being pulsed off if the sensed physiological parameter crosses a threshold value indicative of a decrease in the moisture concentration.