TTFields Transducer Array Capacitor Layout for Hot Electrode Control
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Solution Overview
Problem
Existing TTFields therapy systems face challenges in maintaining optimal temperature control across transducer arrays, leading to uneven heating and reduced treatment efficacy due to higher currents in peripheral electrode elements, which can exceed safety thresholds.
Innovation Solution
Incorporating capacitors in series with peripheral electrode elements to reduce current flow and balance temperature distribution, using capacitors to add impedance and prevent overheating, allowing for increased treatment current delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher current is delivered via transducer arrays to increase treatment efficacy, then treatment efficacy is improved, but temperature of ceramic elements exceeds safety threshold
Solution Approach 1:
The patent applies different capacitance values to different electrode elements based on their local heating characteristics. Peripheral electrode elements that generate more heat are assigned larger capacitance values to reduce their current and temperature, while central elements receive smaller capacitance values. This local differentiation resolves the contradiction by allowing higher overall treatment current while preventing localized overheating at peripheral elements.
2Temperature
If current is reduced to maintain temperature below safety threshold, then temperature control is improved, but treatment efficacy decreases
Solution Approach 1:
Instead of uniformly reducing current across all electrode elements, the patent implements local current reduction only at peripheral elements through targeted capacitance assignment. This allows the system to maintain temperature control where needed while preserving high current delivery at central elements, thereby maintaining treatment efficacy while achieving temperature control.
3Device complexity
If uniform current is delivered to all electrode elements, then system simplicity is maintained, but temperature distribution becomes uneven
Solution Approach 1:
The patent introduces a capacitance assignment mechanism that differentiates between peripheral and central electrode elements. This creates a non-uniform current distribution pattern where peripheral elements receive reduced current through larger capacitance values, while central elements maintain higher current through smaller capacitance values, achieving uniform temperature distribution across the array.
4Power
If more electrode elements operate closer to safety threshold, then treatment current increases, but risk of overheating increases
Solution Approach 1:
The patent preemptively assigns larger capacitance values to peripheral electrode elements before treatment begins, based on the known heating pattern where peripheral elements generate more heat. This preliminary action prevents overheating before it occurs, allowing the system to safely operate more electrode elements closer to the safety threshold by already having compensatory capacitance in place to reduce current where needed.
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
Enhances treatment efficacy by enabling more electrode elements to operate closer to safety thresholds, increasing the total treatment current and improving thermal management in transducer arrays.
Implementation Method 1
Incorporating capacitors in series with peripheral electrode elements to reduce current flow and balance temperature distribution, using capacitors to add impedance and prevent overheating
Implementation Method 2
When a first transducer array is positioned against a person's skin on one side of a person's body, and a second transducer array is positioned against the person's skin on the opposite side of the person's body, and an AC voltage is applied between the leads of the first and second transducer arrays, an electric current is capacitively coupled into the person's body
Implementation Method 3
The plurality of conductive regions includes a plurality of first conductive regions and at least one second conductive region. The first apparatus further comprises a plurality of regions of dielectric material, each of which has (i) a respective front face and (ii) a respective rear face disposed against the front face of a corresponding one of the plurality of conductive regions
Data Source
AI summary
Transducer arrays for applying alternating electric fields (e.g., tumor treating fields a.k.a. TTFields) to a subject's body typically include a plurality of capacitively coupled electrode elements. Often, certain electrode elements on a given array tend to run hotter than other electrode elements. For example, in many anatomical contexts, the corner elements of the transducer array tend to run hotter than the non-corner elements. The spread of operating temperatures between the electrode elements that tend to run hotter and the other electrode elements can be reduced by wiring a capacitor in series with those electrode elements that tend to run hotter (e.g., the corner elements).