Broadband Helical-Linear Antenna for Predictable Tissue Ablation
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Solution Overview
Problem
Microwave tissue ablation devices face issues with non-predictable ablation shapes due to teardrop or cone-shaped energy emission fields, leading to damage to non-targeted tissues and inefficiencies caused by shifting tissue impedance and reflected energy, which can result in device overheating and failure.
Innovation Solution
The development of a tissue ablation device with an asymmetric dipole antenna, featuring a helical and linear arm configuration, capable of operating across multiple frequency bands and maintaining energy absorption peaks, along with a cooling system to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional microwave antenna is used, then the device can operate at prescribed frequencies, but the energy emission field forms a teardrop or cone shape causing damage to non-targeted tissue
Solution Approach 1:
The patent employs an asymmetric dipole antenna design where one arm is longer than the other, creating an asymmetric radiation pattern. This asymmetry allows the energy to be focused in a specific direction (toward the target tissue) while minimizing radiation in other directions, thereby reducing damage to non-targeted tissue and eliminating the teardrop or cone-shaped emission field
2Reliability
If the antenna operates at a fixed frequency, then it can provide stable energy emission, but tissue impedance changes cause the absorption peak to shift away from the operating frequency
Solution Approach 1:
The patent implements a frequency tuning mechanism that allows the antenna's operating frequency to be dynamically adjusted during the ablation procedure. As tissue impedance changes during heating, the system can retune the antenna frequency to track the shifting absorption peak, maintaining optimal energy absorption effectiveness throughout the procedure
Solution Approach 2:
The patent changes the operating frequency parameter of the antenna in response to tissue impedance variations. By monitoring tissue properties and adjusting the frequency parameter accordingly, the system maintains resonance with the tissue's absorption characteristics, ensuring consistent energy delivery despite changing tissue conditions
3Device complexity
If the antenna operates at a single frequency, then the design is simple, but reflected microwave energy causes device overheating and premature failure
Solution Approach 1:
The patent employs frequency modulation or sweeping techniques where the operating frequency is varied over time or across a range. This parameter change prevents sustained resonance conditions that would cause excessive reflected energy, thereby reducing device overheating while adding only moderate complexity to the control 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
The device achieves predictable, spherical ablation volumes with reduced damage to non-targeted tissues and improved energy absorption, enhancing the safety and efficacy of microwave ablation procedures.
Implementation Method 1
Microwave ablation is one of such treatments utilizing electromagnetic radiation to heat tissue
Implementation Method 2
Suitable frequency bands exist in the 915 MHz range (902 to 928 MHz) the 2.45 GHz range (2.402 to 2.483 GHz) and in the 5.8 GHz range (5.725 to 5.875 GHz), although typically the 2.45 GHz range is preferred
Implementation Method 3
It is desired for the antenna should match the tissue impedance so that the maximum peak of energy absorption by the target tissue falls at or about the frequency at which the antenna operates
Implementation Method 4
the maximum peak of energy absorption by the target tissue
Implementation Method 5
The reflected microwave energy may cause the device itself to overheat prematurely which increases the possibility of device failure
Data Source
AI summary
The present invention provides a microwave ablation probe comprising an antenna including a helical arm and a linear arm.