Implanted Graphite Sheets for TTFields Without Tissue Hot Spots
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Solution Overview
Problem
Existing implantable medical devices for delivering alternating electric fields to a target region within a subject's body are bulky, require high numbers of electrodes, operate at low currents to avoid tissue damage, and have limited efficacy due to hot spots and interference from anatomical structures.
Innovation Solution
Implanting electrodes made of graphite sheets within the patient's body to deliver TTFields, utilizing the anisotropic properties of graphite to spread current and heat evenly, reducing the need for larger surface areas and lower currents, and incorporating biocompatible materials for safety and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional implantable electrodes are used to deliver alternating electric fields, then the device can treat tumors, but the device becomes bulky and requires high numbers of electrodes
Solution Approach 1:
The patent divides the electrode system into multiple individual electrodes arranged in an array, where each electrode can be independently controlled. This segmentation allows the delivery of alternating electric fields with different phases and amplitudes to different regions, enabling effective tumor treatment while managing the complexity through modular design
Solution Approach 2:
The patent transitions from traditional point-contact electrodes to planar electrode arrays that utilize two-dimensional surface area. This dimensional change allows multiple electrodes to be distributed across a larger area, reducing the density and bulkiness of the device while maintaining treatment efficacy through spatial distribution of electric field delivery
2Object-affected harmful factors
If traditional electrodes operate at low currents to avoid tissue damage, then tissue safety is maintained, but treatment efficacy is limited
Solution Approach 1:
By dividing the total current delivery across multiple segmented electrodes, the patent distributes the current load. This allows the system to deliver higher total current for improved treatment efficacy while each individual electrode operates at safe current levels that prevent tissue damage, hot spots, and burning
Solution Approach 2:
The patent utilizes alternating current with varying frequencies and phases across different electrodes. By changing the temporal and spatial parameters of current delivery, the system achieves higher effective treatment current while maintaining safe operating conditions through periodic reversal and distribution of current flow
3Reliability
If traditional electrodes are used, then treatment can be delivered, but hot spots are generated causing tissue damage
Solution Approach 1:
The patent segments the electrode delivery system into multiple distributed electrodes that spread current flow across a broader area. This segmentation prevents concentration of current at single points, thereby eliminating hot spots and associated tissue damage while maintaining effective treatment delivery
Solution Approach 2:
The patent designs the electrode array to create equipotential surfaces that distribute electric field energy uniformly across the treatment area. This equipotential design prevents localized energy concentration that would generate hot spots, ensuring safe and effective treatment delivery
4Reliability
If traditional electrodes are used, then treatment can be delivered, but anatomical structures with high resistivity interfere with field penetration
Solution Approach 1:
The patent employs alternating current with optimized frequencies and phases that can penetrate high-resistivity anatomical structures more effectively. By changing the temporal parameters of current delivery and using multiple phases, the system overcomes resistivity barriers and achieves effective treatment delivery to previously inaccessible targets
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 graphite electrodes minimize hot spots, increase the efficacy of the TTFields treatment by allowing higher current delivery, improve patient comfort, and enable treatment of anatomic structures that were previously inaccessible, such as the spinal cord.
Implementation Method 1
utilizing the anisotropic properties of graphite to spread current and heat evenly
Implementation Method 2
utilizing the anisotropic properties of graphite to spread current and heat evenly, reducing the need for larger surface areas and lower currents
Data Source
Figure 1A
Figure 1B
Figure 2~5
AI summary
Alternating electric fields (e.g., tumor treating fields, a.k.a. TTFields) may be applied to a target region in a subject's body via sheets of graphite that are implanted in the subject's body. One or more ports configured for affixation to the subject's body include or connect to one or more mating electrical connectors. Electrical conductors are positioned to route electrical signals between the electrical connector(s) and the sheets of graphite. The alternating electric fields are applied to the target region by applying (via the ports) an alternating voltage between two sheets of graphite that are positioned on opposite sides of the target region.