Circumferential Electrode Array for Uniform Tumor Ablation
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Solution Overview
Problem
Current radiofrequency ablation methods face challenges in uniformly heating large tumors, especially near blood vessels and tumor edges, leading to incomplete treatment and risks of tumor seeding due to the vascular nature of the liver.
Innovation Solution
An electrode array is placed outside the tumor margin, with a radiofrequency power supply applying opposite polarities to adjacent electrodes to prevent shielding effects, promoting a uniform temperature gradient and reducing heat loss through blood vessels, while a holder positions the electrodes to create a cylindrical ablation volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If center-placed electrodes are used for ablation, then the tumor can be heated from the inside, but the temperature distribution becomes non-uniform and electrode temperatures become excessively high leading to loss of effectiveness
Solution Approach 1:
The patent inverts the conventional approach by placing electrodes outside the tumor margin rather than inside the tumor center. This circumferential arrangement allows heating from the outside in, creating a more uniform temperature gradient throughout the tumor volume and preventing excessive electrode temperatures that would occur with center-placed electrodes.
Solution Approach 2:
The patent divides the ablation function into multiple separate electrodes arranged circumferentially around the tumor. Each electrode independently contributes to heating a portion of the tumor, and the combined effect achieves uniform heating of the entire tumor volume. This segmentation also allows for better heat distribution compared to a single center-placed electrode.
2Area of stationary object
If multiple adjacent electrodes with the same polarity are activated simultaneously, then heating coverage is increased, but shielding effects occur between electrodes creating uneven tissue heating
Solution Approach 1:
The patent employs periodic action by sequentially activating electrodes in a round-robin pattern rather than activating all adjacent electrodes with the same polarity simultaneously. Each electrode or alternating electrodes are energized in sequence, which prevents shielding effects between adjacent electrodes of the same polarity while still achieving comprehensive heating coverage through the cumulative effect of sequential activation.
3Temperature
If electrodes are placed inside the tumor tissue, then direct heating is achieved, but tumor seeding risk increases due to piercing and disruption of tissue
Solution Approach 1:
The patent inverts the conventional placement strategy by positioning electrodes outside the tumor margin rather than inserting them into the tumor tissue. This approach maintains direct heating efficiency through the tumor by conducting electrical current through it, while eliminating the mechanical disruption and tissue piercing that would otherwise create pathways for tumor cell seeding.
Solution Approach 2:
The patent uses the surrounding healthy tissue as an intermediary medium to deliver heating energy to the tumor. The electrodes are placed in the healthy tissue adjacent to the tumor, and the electrical current passes through this intermediary tissue to heat the tumor, thereby avoiding direct contact and mechanical disruption of the tumor tissue that would increase seeding risk.
4Productivity
If high power is applied to achieve rapid ablation, then treatment time is reduced, but heat loss through blood vessels increases leading to incomplete treatment
Solution Approach 1:
The patent segments the heating function across multiple circumferentially arranged electrodes, allowing distributed power application around the tumor. This segmentation enables more uniform heat distribution and reduces localized heat loss through blood vessels, as the heating is spread across multiple entry points rather than concentrated at a single center point, thereby improving overall ablation efficiency.
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 ensures reliable and uniform ablation of large tumors, reducing the risk of incomplete treatment and tumor seeding, by directing energy through the tumor center and controlling temperature distribution.
Implementation Method 1
A radiofrequency power supply independently applies electricity to the electrodes in a pattern avoiding simultaneous activation of adjacent electrodes with the same polarity of radiofrequency power
Implementation Method 2
a radiofrequency power supply independently applies electricity to the electrodes in a pattern avoiding simultaneous activation of adjacent electrodes with the same polarity of radiofrequency power to prevent electrostatic shielding effects that reduce the heating between adjacent electrodes having the same polarity of radiofrequency power
Data Source
AI summary
An electrode array supports multiple electrodes and energizes them so that adjacent electrodes do not have the same polarity. In one embodiment, the electrodes are held about a circumference outside and surrounding a tumor and opposed electrodes are energized in a round robin fashion to promote current flow through the center of the tumor from a variety of angles.