Coaxial Cable RF Energy Transmission for Tissue Ablation

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Solution Overview

Problem

Current radio frequency energy transmission devices for biological tissue ablation lack an efficient system for delivering energy to target tissues, particularly in applications like cardiac and tumor ablation, where precise and uniform energy distribution is crucial.

Innovation Solution

A hollow conductive coaxial cable device with a central lumen is used to transmit radio frequency energy, featuring coaxial inner and outer conductors separated by a dielectric medium, allowing for efficient delivery of microwave energy to ablation sites within the body, with a flexible design for navigation and positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional radio frequency energy transmission devices are used, then energy can be delivered to target tissues, but the energy distribution is not uniform and efficient

Engineering Contradiction:
Improveenergy delivery efficiencyVSAvoidenergy distribution uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The transmission system is divided into multiple coaxial cable segments with inner and outer conductors, allowing separate control and optimization of different energy transmission paths. This segmentation enables precise control over energy distribution patterns to achieve uniform delivery across the target tissue area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coaxial cable structure provides different electrical properties at different radial positions, with the inner conductor delivering primary energy and the outer conductor providing shielding and secondary energy distribution. This local quality differentiation ensures uniform energy spread across the treatment zone while maintaining high overall transmission efficiency.

Inventive Principle:
Principle #3Local quality

2Reliability

If a rigid transmission system is used, then energy transmission is stable, but the device cannot be flexibly positioned in the body

Engineering Contradiction:
Improveenergy transmission stabilityVSAvoidpositioning flexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The coaxial cable is constructed with flexible insulating materials and thin-walled conductive structures that maintain electrical integrity while allowing the cable to bend and conform to body cavities and vessels. This flexible shell design enables easy navigation to target sites while preserving stable energy transmission through the flexible structure.

Inventive Principle:
Principle #30Flexible shells and thin films

3Strength

If a solid coaxial cable structure is used, then structural integrity is maintained, but the cable cannot navigate through narrow body passages

Engineering Contradiction:
Improvecable structural integrityVSAvoidcable flexibility for navigation
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The inner conductor is nested within the outer conductor with insulating material in between, creating a compact coaxial structure that maintains structural integrity while minimizing overall diameter. This nested configuration allows the cable to pass through narrow body passages while preserving the strength and electrical performance of the complete coaxial structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 coaxial cable system enables uniform and efficient delivery of radio frequency energy to biological tissues, improving ablation procedures by providing flexible and precise energy distribution, suitable for various medical applications including cardiac and tumor treatments.

Implementation Method 1

a radio frequency energy transmission device for the ablation of biological tissues... The coaxial cable is adapted to connect with an RF signal generator at a proximal end and delivers the RF energy to an ablation member mounted at a distal end portion

Methodology Applied
Scientific EffectRadio frequency energy transmission: Electromagnetic Induction

Implementation Method 2

A dielectric medium is selectively disposed between the inner and outer conductors

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Data Source

PatentEP2194902B1A radio frequency energy transmission device for the ablation of biological tissues
Publication Date: 2014.01.15 MEDWAVE INC
  • EP2194902B1 patent drawingFigure 1~4
  • EP2194902B1 patent drawingFigure 3~5-2
  • EP2194902B1 patent drawingFigure 5-3~6-3

AI summary

A radio frequency energy transmission device comprises a hollow coaxial electrically conductive cable which conducts radio frequency (RF) energy, particularly microwave energy, for the ablation of biological tissue. Coaxial inner and outer conductors extend substantially the entire length of the cable from the proximal end to a distal end portion of the cable. The inner conductor comprises a tubular member having a hollow, axially extending lumen, and the outer conductor comprises a tubular member disposed in a substantially coaxial relationship over at least a portion of the inner conductor. Dielectricity to impede conduction between the inner and outer conductors is introduced with a vacuum or dielectric medium disposed between the inner and outer conductors. An ablating member, which delivers radio frequency energy to body tissue is disposed at a distal end portion of the cable. The ablating member can be a helical coil, a monopole or a microstrip circuit.