Multi-Electrode RF Ablation Signal Control

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Solution Overview

Problem

Current RF ablation technologies face challenges in precisely controlling unipolar and bipolar ablation currents in multi-electrode configurations, leading to unintended energy transfer and interference with other medical devices, due to insufficient metrology and control over ablating currents and voltages.

Innovation Solution

The implementation of a system with multiple electrodes and a signal-generating unit that applies composite signals with different amplitudes and phases, using a processor to measure probe signals and compute an admittance matrix, allowing for precise control of ablation signals to achieve desired unipolar and bipolar currents, minimizing unwanted current components and optimizing energy distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple ablation currents are applied simultaneously to multiple ablation electrodes, then the ablation zone is enlarged and treatment coverage is improved, but unintended bipolar energy transfer and interference with other medical devices occurs

Engineering Contradiction:
Improveablation zone areaVSAvoidunintended bipolar energy transfer
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent segments the ablation current delivery by time, applying currents to electrodes sequentially rather than simultaneously. Each electrode is activated in a separate phase, which eliminates unintended bipolar energy transfer between electrodes while still achieving comprehensive coverage of the ablation zone through multiple phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent incorporates feedback mechanisms that monitor the actual current flow and energy delivery during ablation. The system uses this feedback to adjust and control the ablation parameters, ensuring that only intended unipolar energy transfer occurs and preventing harmful bipolar energy transfer while maintaining effective ablation coverage.

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If multiple ablation currents are applied simultaneously to multiple ablation electrodes, then the ablation zone is enlarged, but interference with other medical devices occurs

Engineering Contradiction:
Improveablation zone areaVSAvoidinterference with other medical devices
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent segments the ablation current delivery by time, applying currents to electrodes sequentially rather than simultaneously. Each electrode is activated in a separate phase, which eliminates unintended bipolar energy transfer between electrodes while still achieving comprehensive coverage of the ablation zone through multiple phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent incorporates feedback mechanisms that monitor the actual current flow and energy delivery during ablation. The system uses this feedback to adjust and control the ablation parameters, ensuring that only intended unipolar energy transfer occurs and preventing harmful bipolar energy transfer while maintaining effective ablation coverage.

Inventive Principle:
Principle #23Feedback

3Device complexity

If insufficient metrology is used for ablating currents and voltages, then the device complexity is reduced, but precise control of unipolar and bipolar ablation currents cannot be achieved

Engineering Contradiction:
Improvemetrology system complexityVSAvoidcontrol precision of ablation currents
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent incorporates feedback mechanisms that monitor the actual current flow and energy delivery during ablation. The system uses this feedback to adjust and control the ablation parameters, ensuring that only intended unipolar energy transfer occurs and preventing harmful bipolar energy transfer while maintaining effective ablation coverage.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex physical metrology systems with computational methods. Instead of using complex hardware measurement systems, the invention uses signal processing and mathematical models to calculate and control the ablation currents, achieving precise control while keeping the physical device complexity manageable.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables precise control of unipolar and bipolar ablation currents, reducing unintended energy transfer and interference, thereby improving the spatial distribution and efficacy of RF ablation while minimizing parasitic frequencies.

Implementation Method 1

radiofrequency (RF) ablation devices... multiple ablation currents are applied, simultaneously, to multiple ablation electrodes... RF power source to produce uniform square-shaped lesions

Methodology Applied
Scientific EffectRadiofrequency heating: Dielectric Heating

Implementation Method 2

A processor is coupled to measure the probe signals received by each of the multiple electrodes, and responsively to the measured probe signals, to control the ablation-signal amplitudes and phases

Methodology Applied
Scientific EffectElectrical impedance measurement: Electrical Impedance Tomography

Implementation Method 3

respective ablation signals, having different, respective ablation-signal amplitudes and phases... cause respective unipolar and bipolar ablation currents to emanate from the electrodes into the body tissue

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3673852B1Controlling bipolar ablation in multi-channel RF ablation devices
Publication Date: 2024.06.12 BIOSENSE WEBSTER (ISRAEL) LTD
  • EP3673852B1 patent drawingFigure 1
  • EP3673852B1 patent drawingFigure 2
  • EP3673852B1 patent drawingFigure 3

AI summary

An ablation system includes multiple electrodes configured to contact body tissue of a patient, including two or more ablation electrodes for contacting respective locations in a target organ and a return electrode. A signal-generating unit includes multiple signal generators, which are configured to apply respective composite signals to respective ones of the ablation electrodes. The composite signals include multiple, respective signal components, including respective ablation signals, having different, respective ablation-signal amplitudes and phases at a common ablation-signal frequency, and respective probe signals having respective probe-signal amplitudes and different respective probe-signal frequencies. A processor is coupled to measure the probe signals received by each of the multiple electrodes, and responsively to the measured probe signals, to control the ablation-signal amplitudes and phases.