Microwave Ablation Probe Choke Structure for Coolant Flow
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Solution Overview
Problem
Existing ablation probes face challenges with coolant flow inefficiency, size limitations, and assembly difficulties due to the use of solid dielectric materials in chokes, which affect cooling efficiency and flexibility, especially for endoscopic applications.
Innovation Solution
A microwave ablation probe design featuring bridging structures formed from angled cuts in the tubular shaft and feed cable, allowing coolant flow through the choke while maintaining electrical connectivity, ensuring efficient cooling and compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid dielectric materials are used in the choke, then the choke structure is stable and electrically effective, but cooling efficiency is reduced and the device size increases
Solution Approach 1:
The patent replaces solid dielectric materials with a porous dielectric material in the choke structure. This porous material allows coolant to flow through it while maintaining the necessary dielectric properties for electrical isolation between the inner and outer conductors. The porous structure provides both cooling pathways and electrical insulation, resolving the contradiction between structural stability and cooling efficiency.
2Reliability
If solid dielectric materials are used in the choke, then the choke provides adequate electrical isolation, but the device flexibility is reduced
Solution Approach 1:
The porous dielectric material maintains electrical isolation between conductors while allowing the probe to be made more flexible. The porous structure reduces the rigidity associated with solid materials, enabling the probe to bend and flex for endoscopic applications while preserving the choke's electrical isolation function.
3Reliability
If traditional choke designs are used, then the choke is electrically effective, but miniaturisation is impeded
Solution Approach 1:
The porous dielectric material allows for a more compact choke design by eliminating the need for separate cooling channels. The material itself provides both dielectric isolation and coolant flow pathways, enabling miniaturisation while maintaining electrical effectiveness.
4Temperature
If coolant flow conduits are added to cool the choke, then cooling efficiency improves, but device complexity increases
Solution Approach 1:
The patent merges the dielectric material function with the cooling structure function. The porous dielectric material serves dual purposes: providing electrical isolation between conductors and providing pathways for coolant flow. This integration eliminates the need for separate cooling conduits, reducing device complexity while maintaining cooling 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
The design enables effective cooling and compact size, facilitating endoscopic use by allowing coolant flow through the choke, enhancing flexibility and ease of assembly.
Implementation Method 1
The choke generates image currents (labelled 'A') opposite in phase to the reflected current (labelled 'B') that help mitigate back currents on the outer conductor 108 of the feed cable
Implementation Method 2
the one or more bridging structures each extend only part way around a longitudinal axis of the ablation probe, thereby allowing coolant to flow through the choke
Implementation Method 3
an applicator arranged to apply microwave radiation to heat surrounding tissue
Implementation Method 4
This causes localised heating and destruction of the malignant cells
Data Source
AI summary
A microwave ablation probe (100). The microwave ablation probe (100) comprises: an applicator (102) arranged to apply microwave radiation to heat surrounding tissue: a feed cable (104) arranged to supply electromagnetic energy to the applicator (102): a tubular shaft (105) arranged to house at least part of the length of the feed cable (104): a coolant flow path (106, 108) via which coolant is able to flow, the coolant flow path being located within a space between the tubular shaft (105) and the feed cable (102); and a choke (112) arranged to reduce power reflected from the applicator (102) along the feed cable (104). The choke comprises one or more bridging structures (114a. 114b. 14c) each provided on a component of the tubular shaft of the feed cable, the one or more bridging structures being arranged to extend across the space between the tubular shaft (105) and the feed cable (104) and form an electrical connection therebetween. The one or more bridging structures (114a. 114b. 114c) each extend only part way around a longitudinal axis of the ablation probe, thereby allowing coolant to flow through the choke (112). The one or more bridging structures (114a. 114b. 114c) are each formed from an angled region cut out from a wall of the component of the tubular shaft or the feeding cable from which they are formed.