TTFields Transducer Arrays Using Flex PCB Temperature Sensing
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Solution Overview
Problem
Existing transducer arrays for Tumor Treating Fields (TTFields) therapy face limitations in temperature monitoring, particularly when using heat-conductive materials, as temperature readings obtained at electrode elements are insufficient to ensure skin temperature remains below safety thresholds, leading to restricted current delivery and potential overheating.
Innovation Solution
The use of a flexible PCB design with temperature sensors positioned at the peripheral section and a separate, low-current trace PCB for temperature monitoring, combined with anisotropic materials to spread current and heat, allowing for more accurate temperature control and efficient current delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are positioned only at electrode elements, then the device complexity is reduced, but the measurement precision of skin temperature is insufficient
Solution Approach 1:
The patent divides the temperature sensing function into two separate systems: (1) electrode elements that apply electrical current for TTFields therapy, and (2) dedicated temperature sensors positioned at peripheral sections that independently monitor temperature. This segmentation allows each component to perform its specialized function optimally without compromising the other, enabling accurate temperature measurement without requiring temperature sensing capabilities at every electrode element.
Solution Approach 2:
The patent introduces a separate temperature sensing system as an intermediary between the electrode elements and the control system. These dedicated temperature sensors act as mediators that indirectly monitor the thermal effects of current delivery by measuring temperature at peripheral sections, providing accurate temperature data without requiring direct temperature measurement at each current-delivering electrode element.
2Productivity
If current delivery is increased to improve treatment efficacy, then the therapeutic effect is enhanced, but skin temperature exceeds safety thresholds
Solution Approach 1:
The patent implements a feedback control system where dedicated temperature sensors continuously monitor skin temperature at peripheral sections, and this temperature information is fed back to control the current delivery. When temperature approaches safety thresholds, the system automatically adjusts current levels, enabling sustained high-current therapy while preventing overheating through real-time temperature-based feedback control.
Solution Approach 2:
The patent positions temperature sensors at peripheral sections before the full thermal effects of current delivery manifest at central electrode locations. This preliminary positioning allows the system to detect temperature trends early and adjust current delivery proactively, preventing temperature from reaching dangerous levels rather than reacting after overheating occurs.
3Reliability
If a single PCB is used for both high current delivery and low current temperature sensing, then the device complexity is reduced, but the manufacturing precision and reliability deteriorate
Solution Approach 1:
The patent segments the PCB system into two separate boards: a first PCB dedicated to high-current delivery to electrode elements, and a second flexible PCB dedicated to low-current temperature sensing. This physical separation eliminates electrical interference between high and low current circuits, ensuring reliable temperature measurements are not corrupted by high-current noise, while maintaining manageable device complexity through functional specialization.
Solution Approach 2:
The patent applies different design qualities to different parts of the system: the first PCB is optimized for high-current handling with appropriate trace widths and thermal management, while the second flexible PCB is optimized for low-current sensing with fine traces and flexibility for positioning. Each PCB has local quality characteristics tailored to its specific function, improving overall system reliability without requiring a single complex PCB to accommodate all requirements.
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 design enables safer and more efficient TTFields therapy by accurately monitoring skin temperature across a larger area, allowing for higher current delivery without exceeding safety thresholds, reducing costs through separate PCBs for high and low current traces.
Implementation Method 1
a plurality of temperature sensors positioned at a peripheral section of the transducer array
Implementation Method 2
anisotropic materials to spread current and heat
Implementation Method 3
When an AC voltage is applied between opposing electrode assemblies, an AC current is coupled through the electrode assemblies and into the subject's body
Implementation Method 4
a first layer of conductive adhesive or conductive gel disposed on and in front of both the first PCB and the second PCB
Implementation Method 5
a layer of dielectric material with a high dielectric constant positioned between the metal layer and the subject's skin
Data Source
AI summary
Alternating electric fields (e.g., Tumor Treating Fields or TTFields) can be applied to a subject's body using an apparatus (e.g., a transducer array) that includes a first PCB that has metal pads for coupling an AC signal into the subject's body at high currents, and a second, less expensive PCB that can only handle lower currents. The first PCB is located at a central portion of the apparatus, and the second PCB is located at a peripheral portion of the apparatus. Temperature sensors (e.g., thermistors) are electrically connected to the second PCB. In some embodiments, the second PCB is significantly larger than the first PCB.