TTFields Electrode Arrays with Local Active-Area Overheating Control
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Solution Overview
Problem
Existing TTFields therapy systems face issues with maintaining effective electrical contact between electrode elements and the body, leading to overheating and reduced treatment efficacy due to factors like hydrogel drying or hair growth, which necessitate current reduction across all elements, affecting field strength.
Innovation Solution
The system employs sets of electrode elements with individually adjustable active areas, using separate conductors for each first electrode and a shared conductor for second electrodes, along with temperature sensors, to independently control current distribution and prevent overheating by reducing current only in overheating areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the current amplitude is increased to maintain effective electric field strength, then treatment efficacy is improved, but skin temperature increases causing overheating and safety issues
Solution Approach 1:
The transducer array is divided into multiple independently controllable electrode elements, each with its own temperature sensor and current control circuitry. This segmentation allows the system to monitor and control temperature at each electrode element separately, enabling selective current reduction only in overheating areas while maintaining full current in normal areas, thus preserving overall treatment efficacy while preventing localized overheating.
Solution Approach 2:
The system dynamically adjusts the current amplitude parameter based on real-time temperature measurements from thermistors. When temperature exceeds a threshold, the control circuitry automatically reduces the current amplitude to safe levels. This parameter adjustment is performed locally at each electrode element based on its specific temperature conditions, resolving the contradiction between maintaining effective field strength and preventing overheating.
2Temperature
If the current is reduced to prevent overheating, then skin temperature safety is improved, but electric field strength decreases reducing treatment efficacy
Solution Approach 1:
The system implements local quality control by allowing each electrode element to operate with different current amplitudes based on its local temperature conditions. Electrode elements in normal temperature zones maintain full current for effective treatment, while only those in overheating zones reduce current. This local differentiation resolves the contradiction by applying current reduction selectively rather than globally, preserving treatment efficacy in safe areas while ensuring temperature safety in hot areas.
3Measurement precision
If separate conductors are used for each electrode element to enable individual current control, then temperature control precision is improved, but cable complexity increases
Solution Approach 1:
The system merges the current delivery function and temperature sensing function into a single integrated cable structure. Each cable contains multiple conductors that serve dual purposes: delivering current to electrode elements and carrying temperature sensor signals back to the control circuitry. This merging reduces the number of separate cables needed while maintaining the precision of individual temperature control, resolving the contradiction between control precision and cable complexity.
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 maintains effective electric field strength by preventing overheating of individual electrode elements, ensuring consistent treatment efficacy without the need for complete shutdown, and reduces cable complexity by sharing conductors for current output and temperature sensing.
Implementation Method 1
each of the at least four temperature sensors is disposed in thermal contact with a respective one of the sets of electrode elements
Implementation Method 2
The AC signal generator (a) sends an AC current through one pair of arrays 21, 22 during a first period of time, which induces an electric field with a first direction through the tumor
Implementation Method 3
Each electrode element includes an electrically conductive substrate with a dielectric layer (more specifically, a layer of ceramic material with a high dielectric constant) disposed thereon
Implementation Method 4
each of the at least four temperature sensors is disposed in thermal contact with a respective one of the sets of electrode elements
Data Source
AI summary
Tumor treating fields (TTFields) can be delivered to a subject's body using electrode elements that are arranged in sets, wherein each set includes a respective first electrode element and a respective second electrode element disposed in thermal contact with each other. Individual first conductors provide an electrically conductive path between each of the first electrode elements and a respective pin of a connector. And a second conductor provides an electrically conductive path between all of the second electrode elements and another pin of the connector. Temperature sensors are disposed in thermal contact with each set of electrode elements. Because the electrode elements are arranged in sets, the current that flows through any given set can be reduced (with respect to its maximum value) by switching off the first electrode element within the given set, in order to prevent the area that corresponds to the given set from overheating.