Ablation Cable Assembly With Circumferential Heat Spreading
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Solution Overview
Problem
Existing cable assemblies for medical ablation devices, particularly those using radio frequency or microwaves, face issues with non-uniform temperature distribution and thermal hot spots due to non-rotationally symmetric cross-sections and power dissipation, which can lead to harmful surface temperatures, especially when in contact with human tissue.
Innovation Solution
A cable assembly design featuring a coaxial cable with a dielectric layer, an outer conductor, and a thermal conductive layer that encompasses the coaxial cable and cooling lines, distributing thermal energy circumferentially to reduce hot spots, combined with a dual cooling line system for enhanced cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the cross-section of the cable assembly is non-rotationally symmetric and varies over length, then the cable can be designed to fit specific spatial constraints, but non-uniform temperature distributions and thermal hot spots occur
Solution Approach 1:
The patent applies asymmetry by intentionally designing a non-rotationally symmetric cross-section for the cable assembly, where the inner conductor, dielectric layer, and outer conductor have asymmetric configurations. This asymmetric design allows the cable to adapt to specific spatial constraints and installation requirements while maintaining controlled temperature distribution through the asymmetric thermal pathways.
Solution Approach 2:
The patent implements local quality by varying the cross-sectional properties (inner conductor diameter, dielectric thickness, outer conductor configuration) at different positions along the cable length. This allows different sections of the cable to have optimized thermal and electrical characteristics tailored to local requirements, managing heat distribution non-uniformly along the cable.
2Power
If the power level is increased to treat cancerous tissue effectively, then the ablation capability is improved, but the surface temperature of the cable assembly rises to harmful levels
Solution Approach 1:
The patent converts the harmful thermal energy that would otherwise create dangerous hot spots into a beneficial distributed thermal field. By using asymmetric cross-sectional designs and multiple dielectric layers with different thermal conductivities, the cable transforms concentrated heat generation into distributed heat dissipation, allowing high power operation while maintaining safe surface temperatures.
Solution Approach 2:
The patent employs composite material structures with multiple dielectric layers having different thermal and electrical conductivity properties. These composite layers are arranged asymmetrically to create optimized thermal pathways that conduct heat away from the inner conductor while maintaining electrical insulation, enabling high power transmission without excessive surface heating.
3Loss of energy
If the cross-section of the inner conductor is increased to reduce power dissipation, then the heat radiation is reduced, but the catheter/cable diameter increases and flexibility is reduced
Solution Approach 1:
The patent changes multiple parameters simultaneously rather than relying on a single parameter adjustment. By modifying the asymmetric cross-sectional dimensions, dielectric layer thicknesses, thermal conductivities, and outer conductor configurations, the patent achieves reduced power dissipation while maintaining a compact cable diameter and preserving flexibility for clinical use.
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 effectively maintains the cable assembly's surface temperature below harmful levels, ensuring safety and flexibility, even during high-power treatments without the need for extensive cooling agents, by utilizing a thermal conductive layer and dual cooling lines to manage thermal energy distribution and absorption.
Implementation Method 1
a thermal conductive layer (7) which in a cross-sectional view encompasses the coaxial cable (2) and the first cooling line (6) in a circumferential manner and is configured to reduce a thermal peak caused by the coaxial cable (2), by distributing thermal energy around the coaxial cable (2) and the first cooling line (6) in a circumferential manner
Implementation Method 2
a first cooling line (6) arranged inside the thermal conductive layer (7) and in contact with the coaxial cable (2), wherein the cable assembly (1) comprises a second cooling line (8) arranged inside the thermal conductive layer (7)
Data Source
AI summary
A cable assembly (1) for medical radio frequency or microwave ablation. The cable assembly includes a coaxial cable (2) with an inner conductor (3), encompassed by a dielectric layer (4), encompassed by an outer conductor (5). The cable assembly (1) further includes a first cooling line (6) and a thermal conductive layer (7), which in a cross-sectional view encompasses the coaxial cable (2) and the first cooling line (6) in a circumferential manner. The thermal conductive layer (7) is configured to reduce a thermal peak caused by the coaxial cable (2) when transferring energy, by distributing thermal energy around the coaxial cable (2) and the first cooling line (6) in a circumferential manner.