Deformable Template Head Model for TTFields Electrode Placement

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Solution Overview

Problem

The current methods for optimizing the placement of transducer arrays for Tumor Treating Fields (TTFields) therapy are labor-intensive and require significant human intervention due to the complexity of creating personalized computational head models for each patient, especially when dealing with anatomical variations and tumors.

Innovation Solution

A method using a deformable template of a healthy individual's head model to generate a customized realistic head model for each patient, reducing the need for extensive human labor and enabling fully automatic or semi-automatic optimization of transducer array layouts by applying non-rigid deformation and incorporating additional imaging data like DTI and Wept for improved conductivity representations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If personalized computational head models are constructed for each patient using conventional methods, then the accuracy of electromagnetic field distribution simulation is improved, but the time and human labor required for model creation increases significantly

Engineering Contradiction:
Improveaccuracy of electromagnetic field distribution simulationVSAvoidtime and human labor for model creation
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

A population-averaged head model is pre-computed and stored in a database before actual patient treatment planning. This pre-computed model contains averaged anatomical structures and tissue properties that can be rapidly adapted to individual patients through deformation transformations, eliminating the need to construct detailed personalized models from scratch for each patient

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transforms the complex problem of creating personalized head models by changing the approach from modeling individual anatomical variations to using a population-averaged model that can be deformed to match patient-specific MRI data. This parameter transformation reduces computational complexity while maintaining sufficient accuracy for treatment planning

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional model construction methods are used with manual segmentation and mesh regularization, then anatomical accuracy is maintained, but the complexity and labor intensity of the process increases

Engineering Contradiction:
Improveanatomical accuracy of head modelVSAvoidcomplexity of model construction process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of manually segmenting and constructing meshes for each patient's head anatomy, the patent uses a pre-computed population-averaged head model as a template that can be deformed and adapted to individual patients. This copying approach with subsequent deformation maintains anatomical accuracy while dramatically reducing manual intervention requirements

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The population-averaged head model serves as a universal template that can be applied to multiple patients through deformation transformations. This single multi-functional model replaces the need for separate personalized model construction processes for each patient, reducing both complexity and labor

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If fully automatic optimization of transducer array layout is implemented, then productivity and efficiency are improved, but the accuracy of electrode positioning may deteriorate due to loss of expert human judgment

Engineering Contradiction:
Improveefficiency of treatment planningVSAvoidaccuracy of electrode positioning
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system incorporates feedback mechanisms where the pre-computed population-averaged model and automated optimization algorithms provide initial recommendations, which can then be refined and adjusted based on clinician expertise and patient-specific considerations. This feedback loop maintains high productivity while preserving the value of human judgment

Inventive Principle:
Principle #23Feedback

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

This approach significantly reduces the time and human intervention required to create personalized head models, allowing for more efficient optimization of TTFields delivery, thereby improving the efficacy of the treatment by maximizing electric field intensity in target regions with minimal manual effort.

Implementation Method 1

A method using a deformable template of a healthy individual's head model to generate a customized realistic head model for each patient, reducing the need for extensive human labor and enabling fully automatic or semi-automatic optimization of transducer array layouts by applying non-rigid deformation

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

TTFields are low intensity (e.g., 1-3 V/cm) alternating electric fields within the intermediate frequency range (100-300 kHz), which may be used, for example, to treat tumors. These alternating electric fields are induced non-invasively by transducer arrays

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 3

Trans-cranial Direct Current Stimulation (TDCS), Transcranial Magnetic Stimulation (TMS), and Tumor Treating Fields (TTFields). These treatments rely on delivery of low-frequency electromagnetic fields to target regions within the brain

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3974024B1Electrode positioning optimized using deformable templates
Publication Date: 2024.08.21 NOVOCURE GMBH
  • EP3974024B1 patent drawingFigure 1
  • EP3974024B1 patent drawingFigure 2~3
  • EP3974024B1 patent drawingFigure 4~5

AI summary

A method for improving an electrotherapeutic treatment and an electrotherapeutic treatment device, the method comprising: receiving an image of a body area of a patient; identifying abnormal tissue in the image; generating a data set with the abnormal tissue masked out; deforming a model template in space so that features in the deformed model template line up with corresponding features in the data set; placing data representing the abnormal tissue back into the deformed model template; generating a model of electrical properties of tissues in the body area based on the deformed and modified model template; and determining an electrode placement layout that maximizes or minimizes a target function of an electric field in the abnormal tissue by using the model of electrical properties to simulate electromagnetic field distributions in the body area caused by simulated electrodes placed respective to the body area. The layout can then be used as a guide for placing electrodes respective to the body area to apply TTFields to the body area.