TTFields Transducer Array Metallization Area Variation
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Solution Overview
Problem
Existing transducer arrays used for applying Tumor Treating Fields (TTFields) face issues with overheating, particularly at the corner elements, which leads to a reduction in current and treatment efficacy due to the need to lower the applied voltage to prevent temperature thresholds from being exceeded.
Innovation Solution
The solution involves reducing the capacitance of the corner elements relative to the centrally located elements in the transducer array. This is achieved by varying the area of the conductive metallization on the back side of the ceramic elements, using thinner or lower dielectric constant materials, or ablating conductive links to disconnect sub-regions, thereby reducing the active area and capacitance of the corner elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the capacitance of each transducer array element is increased to achieve higher current, then the treatment efficacy is improved, but the temperature of the elements increases causing overheating
Solution Approach 1:
The patent applies local quality by making corner elements have different capacitance values than central elements. Specifically, corner elements are designed with lower capacitance (smaller conductive region area) while central elements maintain higher capacitance. This local differentiation allows current to be distributed more evenly across the array, preventing corner elements from overheating while maintaining high overall current delivery for effective treatment.
2Temperature
If the voltage is lowered to prevent corner elements from overheating, then the temperature safety threshold is maintained, but the current delivery and treatment efficacy are reduced
Solution Approach 1:
The patent implements preliminary action by pre-configuring corner elements with lower capacitance values before operation begins. This anticipatory design prevents the corner elements from reaching dangerous temperature thresholds during normal operation, allowing the system to maintain higher voltage and current levels throughout treatment without needing to reduce power to prevent overheating.
3Ease of manufacture
If uniform capacitance is used across all elements, then the design is simple and manufacturing is easier, but corner elements overheat due to higher current density
Solution Approach 1:
The patent applies local quality by making corner elements have different capacitance values than central elements. Specifically, corner elements are designed with lower capacitance (smaller conductive region area) while central elements maintain higher capacitance. This local differentiation allows current to be distributed more evenly across the array, preventing corner elements from overheating while maintaining high overall current delivery for effective treatment.
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
By preemptively reducing the current through the corner elements, the temperature of these elements is lowered, allowing for a balanced distribution of temperature across all elements. This enables an increase in the voltage amplitude, resulting in higher current delivery and improved treatment efficacy without overheating.
Implementation Method 1
Because increasing the capacitance of each of the transducer arrays results in a corresponding increase of current
Implementation Method 2
Each of the regions of dielectric material has (i) a respective front face and (ii) a respective rear face disposed against the front face of a respective one of the conductive regions
Implementation Method 3
The area of each of the second conductive regions is at least 10% smaller than the area of each of the first conductive regions
Data Source
AI summary
Conventional transducer arrays for applying tumor treating fields (TTFields) include a set of individual electrode elements, and the more peripherally-located electrode elements (e.g., electrode elements at the corners or edges of the transducer arrays) tend to get hotter than the more centrally located electrode elements. This situation can be ameliorated by reducing the capacitance of the more peripherally-located electrode elements. Reducing the capacitance of those elements reduces the current that travels through those elements (at any given voltage), which reduces the temperature of those elements. Once the capacitance of the more peripherally-located electrode elements is reduced, higher voltages can be used without overheating. This leads to an increase in the overall current, which can improve the efficacy of the TTFields treatment.