Antenna Assembly Microwave Ablation Choke Ring Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current microwave ablation antennas face issues with microwave escape along the exterior conductor of coaxial cables, leading to irregular ablation zones and potential overheating of the ablation needle, which can result in medical accidents.
Innovation Solution
An annular composite structure comprising a nonmetallic and metallic layer around the coaxial cable is used to inhibit backward microwave propagation, with specific dimensions and materials to ensure effective cooling and prevent overheating, allowing circulation water to reach the ablation zone without the need for high dielectric constant stabilizing media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a choke ring (groove) is used to inhibit backward microwave propagation, then the ablation zone becomes rounder, but the head of the ablation needle overheats and may burn out or crack
Solution Approach 1:
The patent introduces circulation water as an intermediary cooling medium that flows through the ablation needle to absorb excess heat from the head, preventing overheating while maintaining the choke ring's ability to shape the ablation zone
Solution Approach 2:
The patent changes the thermal parameter management by introducing active cooling through water circulation, which alters the temperature distribution along the ablation needle, particularly reducing the head temperature while maintaining effective ablation temperature at the tip
2Stability of the object's composition
If a high dielectric constant medium is filled to stabilize the choke ring performance, then the microwave propagation is stabilized, but the circulation water cannot reach the head of the ablation needle
Solution Approach 1:
The patent removes the high dielectric constant filling medium from the ablation needle interior, extracting the obstacle that prevented water circulation, while maintaining choke ring performance through alternative stabilization methods
Solution Approach 2:
The patent uses circulation water as a dual-function medium that both cools the ablation needle and serves as the propagation medium for microwaves, eliminating the need for high dielectric constant materials while maintaining system stability
3Device complexity
If no choke technology is used, then the structure is simpler, but microwaves escape backwards along the exterior conductor causing ellipsoidal ablation zones
Solution Approach 1:
The patent uses a composite structure combining the choke ring with water-cooled channels, integrating the microwave containment function with the cooling function in a unified design that maintains structural simplicity while achieving the desired ablation zone shape
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 effectively creates a uniform ablation zone and prevents overheating of the ablation needle, ensuring safe and controlled microwave ablation procedures by inhibiting backward microwave propagation and maintaining stable temperatures.
Implementation Method 1
an annular composite structure for inhibiting an electromagnetic wave propagated backwards along the coaxial cable is provided around the coaxial cable
Implementation Method 2
microwave ablation uses the heat effect of microwaves in polar molecules, such as water, to heat the pathology area to a high temperature instantaneously
Implementation Method 3
it is required to fill a high dielectric constant medium stable with respect to temperature. This results in the circulation water not arriving at the head of the ablation needle
Implementation Method 4
the circulation water not arriving at the head of the ablation needle
Data Source
AI summary
An antenna assembly for microwave ablation can include a radiator for emitting a microwave for ablation; a coaxial cable for transmitting the microwave for ablation generated by a microwave generator to the radiator; an annular composite structure is provided around the coaxial cable for inhibiting an electromagnetic wave from propagating backwards along the coaxial cable. In some embodiment, the annular composite structure comprises an annular nonmetallic layer and an annular metallic layer located outside the annular nonmetallic layer. In some embodiments, the annular metallic layer is electrically insulated from the coaxial cable. In some embodiments, the antenna assembly can be used with a microwave ablation needle. The annular composite structure can inhibit the backward propagation of the microwave along the coaxial cable exterior wall. In some embodiments, circulation water enters the radiation zone, to avoid high temperatures of the head the ablation needle.