Biphasic Waveform Control for Selective Cell Ablation
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Solution Overview
Problem
Existing electrical ablation techniques face challenges in achieving high efficacy and tissue selectivity while avoiding muscle stimulation, particularly due to the limitations of monophasic and biphasic waveforms.
Innovation Solution
A device and method for generating energy for electrical ablation that includes a voltage source, a capacitor bank, and an output stage with power selector switches and electrode selector switch pairs, coupled with a feedback circuit for monitoring current and voltage to control the ablation process, allowing for the delivery of a biphasic electrical output with an extended interpulse period to avoid muscle stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monophasic waveform is used for IRE, then cell death efficacy is improved, but muscle stimulation occurs requiring paralytic
Solution Approach 1:
The waveform is segmented into multiple phases (first polarity phase and second polarity phase) with an extended interpulse period between them. This segmentation allows the first phase to deliver sufficient charge for cell death while the extended interpulse period prevents muscle stimulation, and the second phase restores charge balance.
Solution Approach 2:
The waveform uses periodic pulsed delivery with specific duty cycles and interpulse periods. By controlling the timing and duration of each phase periodically, the system achieves effective tissue ablation during the pulse phases while the extended interpulse periods prevent sustained muscle contraction.
2Object-affected harmful factors
If biphasic waveform is used to avoid muscle stimulation, then muscle stimulation is reduced, but ablation efficacy decreases at same energy level
Solution Approach 1:
The system changes multiple parameters simultaneously: extending the interpulse period between phases, adjusting the duty cycle of each phase, and optimizing the amplitude of the bipolar waveform. These parameter changes allow the biphasic waveform to maintain ablation efficacy comparable to monophasic waveforms while preventing muscle stimulation through the extended interpulse period.
3Reliability
If power is raised to make biphasic waveform more effective, then ablation efficacy is improved, but thermal ablation risk increases
Solution Approach 1:
The use of periodic pulsed waveforms with extended interpulse periods allows adequate cooling intervals between energy delivery phases. This periodic action delivers sufficient total energy for effective ablation while preventing continuous heating that would lead to thermal damage, thus achieving non-thermal electroporation ablation.
Solution Approach 2:
The system maintains continuous monitoring and adjustment of waveform parameters to ensure effective energy delivery for ablation while continuously preventing thermal accumulation through the extended interpulse periods, achieving sustained non-thermal ablation efficacy.
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 solution enables effective electrical ablation with high efficacy and tissue selectivity, avoiding muscle stimulation and achieving therapeutic outcomes similar to monophasic waveforms while minimizing side effects.
Implementation Method 1
a capacitor bank, and an output stage coupling the capacitor bank to a plurality of output nodes
Implementation Method 2
Electroporation refers to a phenomenon in which the plasma membrane of a cell exposed to high voltage pulsed electric fields becomes temporarily permeable due to destabilization of the lipid bilayer
Implementation Method 3
a feedback circuit for monitoring current and voltage to control the ablation process
Data Source
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AI summary
Methods and devices for performing ablation. In some examples an ablation delivery system is configured to allow separate voltage levels of a capacitor stack to be accessed for use in therapy delivery. Ablation therapy systems switchable between current and voltage controlled output are described. Methods of treating a patient using adjustable interphase or interpulse delay are disclosed as well.