TTFields Electrode Assembly With Anisotropic Sheet for Higher Current

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Solution Overview

Problem

Existing tumor treating field (TTFields) electrode assemblies experience uneven current distribution leading to hot spots, limiting the maximum current that can be applied due to safety temperature thresholds, which in turn restricts the strength of the TTFields treatment.

Innovation Solution

Incorporating a sheet of anisotropic material with directional thermal and electrical properties into the electrode assembly to evenly distribute current and heat, minimizing hot spots and allowing higher current application without exceeding safety temperature thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher current is applied to increase TTFields efficacy, then treatment effectiveness is improved, but skin temperature exceeds safety threshold due to hot spots

Engineering Contradiction:
ImproveTTFields treatment efficacyVSAvoidskin temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent applies anisotropic material with directionally varying thermal conductivity to different regions of the electrode assembly. The material has high thermal conductivity in the lateral direction (parallel to skin surface) to spread heat away from hot spots, while maintaining low thermal conductivity in the vertical direction (perpendicular to skin) to prevent excessive heat transfer into the body. This local directional property resolution allows higher current application without exceeding skin temperature safety thresholds.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the thermal conductivity parameter of the electrode assembly by introducing anisotropic material. The material exhibits different thermal conductivity values in different directions (k_parallel >> k_perpendicular), fundamentally altering the heat distribution pattern from concentrated hot spots to laterally dispersed temperature profiles, enabling higher current delivery while maintaining skin temperature below 41°C.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If current is limited to maintain skin temperature below safety threshold, then skin safety is ensured, but TTFields treatment strength is restricted

Engineering Contradiction:
Improveskin safetyVSAvoidTTFields treatment strength
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The anisotropic material creates different thermal management zones: lateral regions efficiently conduct heat away from electrode-skin contact points, while vertical regions maintain thermal insulation. This local directional quality enables the system to operate at higher currents with improved treatment strength while maintaining skin safety through enhanced lateral heat dissipation pathways.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The anisotropic material acts as an intermediary thermal management layer between the electrode elements and the skin. It mediates heat flow by preferentially conducting heat laterally away from the skin interface while limiting vertical heat transfer into the body, thus enabling higher current operation without compromising skin safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 anisotropic material enables increased current delivery, enhancing the efficacy of TTFields treatment by maintaining skin temperature below safety limits and improving therapeutic outcomes.

Implementation Method 1

a sheet of material having anisotropic thermal properties... Thermal conductivity of the sheet in directions that are parallel to the front face is more than two times higher than the thermal conductivity of the sheet in a direction that is perpendicular to the front face

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a sheet of material having anisotropic electrical properties... the resistance of the sheet in directions that are parallel to the front face is less than half of the resistance of the sheet in a direction that is perpendicular to the front face

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4344414B1Electrode assembly for applying tumor treating fields with a sheet of anisotropic material
Publication Date: 2026.04.15 NOVOCURE GMBH
  • EP4344414B1 patent drawingFigure 1A~1B
  • EP4344414B1 patent drawingFigure 1C~1D
  • EP4344414B1 patent drawingFigure 2~3A

AI summary

Alternating electric fields (e.g., TTFields) may be applied to a subject's body using one or more electrode assemblies that includes a sheet of anisotropic material, at least one layer of conductive material disposed on the front face of the sheet of anisotropic material, and an electrode element positioned behind the sheet of anisotropic material. The electrode element has a front face disposed in electrical contact with the rear face of the sheet of anisotropic material. The sheet of anisotropic material spreads both heat and current out in directions that are parallel to the front face of the sheet, which eliminates or at least minimizes hot spots on the electrode assembly. This in turn makes it possible to increase the current without exceeding a temperature safety threshold (e.g., 41° C).