TTFields Electrode Impedance Tomography for Subject-Specific Planning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for estimating the field intensity and positioning of electrode arrays for Tumor Treating Fields (TTFields) treatment rely on conductivity values from scientific literature, leading to inaccurate estimates of electric field intensity in tumors due to variations in individual tissue conductivities.
Innovation Solution
Measure actual impedance or conductance between electrode elements on a subject's body to determine optimized electric field intensity and positioning, using a set of electrodes to calculate impedance or conductance at each voxel corresponding to the target region and generate a treatment plan based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If literature-based conductivity values are used to model tissue electrical characteristics, then the treatment planning process is simplified and can be performed without additional measurements, but the accuracy of electric field intensity estimation in the tumor deteriorates due to individual variations in tissue conductivity
Solution Approach 1:
The patent implements feedback by measuring actual impedance values from the patient's body using electrode arrays, then using these measurements to update and refine the electrical characteristics model for treatment planning. This closed-loop approach ensures the model reflects the patient's actual tissue properties rather than relying solely on literature values, thereby improving estimation accuracy while maintaining procedural efficiency
Solution Approach 2:
The system performs self-characterization by automatically measuring impedance values directly from the patient's body through integrated electrode arrays. This eliminates the need for separate, complex measurement procedures and allows the treatment planning system to obtain accurate electrical characteristics data inherently part of the treatment setup process, resolving the contradiction between ease of planning and measurement accuracy
2Measurement precision
If impedance measurements are taken between multiple electrode elements to determine voxel-specific impedance values, then the accuracy of electric field intensity determination improves, but the complexity of the measurement and calculation process increases
Solution Approach 1:
The patent divides the measurement process into discrete impedance measurements between specific electrode element pairs that correspond to voxel locations. By segmenting the complex 3D measurement problem into manageable 2D electrode pair measurements, the system achieves voxel-specific impedance values without requiring an overly complex measurement apparatus or procedure
Solution Approach 2:
The electrode arrays serve multiple functions: they deliver tumor treating fields therapeutic voltage and simultaneously perform impedance measurements for treatment planning. This multi-functionality eliminates the need for separate measurement devices, reducing overall system complexity while maintaining high measurement precision through the same physical electrodes
3Measurement precision
If actual impedance measurements from the subject are used instead of literature-based conductivity values, then the accuracy of treatment planning improves, but additional measurement time and procedural steps are required
Solution Approach 1:
The patent merges the impedance measurement step with the electrode array application process. As the electrodes are positioned on the patient's body for therapy delivery, impedance measurements are simultaneously or immediately performed, eliminating the need for separate measurement sessions. This integration reduces the time penalty while maintaining the accuracy benefits of subject-specific measurements
Solution Approach 2:
The system performs impedance measurements during the initial electrode positioning phase before full treatment begins. By completing measurements during this necessary setup period rather than requiring additional dedicated measurement time, the patent captures accurate baseline electrical characteristics without extending the overall treatment planning timeline
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
Provides accurate determination of electric field intensity and optimized electrode positioning, improving treatment efficacy by using actual subject-specific impedance measurements instead of literature-based conductivity assumptions.
Implementation Method 1
sequentially measuring, during a first window of time, a respective impedance or conductance between each of the N electrode elements in the first set and each of the M electrode elements in the second set
Implementation Method 2
treating a target region in a subject's body using alternating electric fields
Data Source
Figure 1A~1D
Figure 2
Figure 3
AI summary
Treatment of a target region using alternating electric fields (e.g., TTFields) may be planned by determining, based on a plurality of impedance measurements obtained during a first window of time, a first impedance at each of a plurality of voxels that correspond to the target region. Then, based on the first impedances, a plan for treating the target region with alternating electric fields is generated. Subsequently, an electric field may be induced in the target region based on the plan. In some embodiments, a baseline MRI of the target region is obtained, and contemporaneous baseline impedances are registered to the MRI. In these embodiments, the plan for treating the target region is further based on a comparison between the first impedances and the baseline impedances.