Tumor Electrical Stimulation Devices With Four-Wire Impedance Sensing
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Solution Overview
Problem
Existing electrical impedance measurement methods for biological tissues, particularly in the context of cancerous tumors, suffer from interference due to the inclusion of device component impedances, leading to inaccurate tissue impedance readings, which hampers effective therapy guidance.
Innovation Solution
The use of a four-wire impedance measurement system to isolate tissue impedance by separating supply and sensing electrodes, reducing interference from device components and enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a two-wire impedance measurement system is used, then the device complexity is reduced, but the measurement precision deteriorates due to inclusion of device component impedances
Solution Approach 1:
The measurement system is segmented into separate current supply electrodes and voltage sensing electrodes. This segmentation allows the current to flow through the tissue while the voltage measurement is taken independently, preventing the device component impedances from being included in the tissue impedance measurement.
Solution Approach 2:
The patent introduces separate sensing electrodes as intermediaries that measure the voltage drop across the tissue without carrying the measurement current. These intermediary sensing electrodes isolate the voltage measurement path from the current supply path, eliminating the interference of device component impedances.
2Device complexity
If supply and sensing functions are combined in the same electrodes, then the device complexity is reduced, but the measurement precision deteriorates due to interference from device components
Solution Approach 1:
The electrode system is segmented into distinct current supply electrodes and voltage sensing electrodes. This segmentation separates the current-carrying function from the voltage-sensing function, allowing independent optimization of each function and eliminating the interference that would occur if the same electrodes performed both functions.
Solution Approach 2:
The voltage sensing function is extracted from the current supply electrodes and assigned to separate sensing electrodes. This extraction removes the harmful interference of device component impedances from the measurement path while preserving the current supply function.
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
Accurate impedance measurements of biological tissues, including cancerous tumors, are achieved, providing valuable clinical insights for therapy guidance and ensuring optimal device performance by minimizing interference from device components.
Implementation Method 1
measuring an impedance of the biological tissue at the at least two electric field strengths
Implementation Method 2
The use of a four-wire impedance measurement system to isolate tissue impedance by separating supply and sensing electrodes
Implementation Method 3
When placed in an electric field, biological tissues can store electromagnetic energy due to the displacement of the positive or negative charges carried on the electrically active molecules therein. Displacement of the positive and negative charges within the biological tissue can result in a net polarization of the biological tissue.
Implementation Method 4
The electrically active molecules of biological tissues also give rise to dielectric properties within the biological tissues
Data Source
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AI summary
The present invention relates to a medical device for treating a cancerous tumor comprising: an electric field generating circuit configured to generate one or more electric fields at or near a site of the cancerous tumor; control circuitry in communication with the electric field generating circuit, the control circuitry configured to control delivery of the one or more electric fields from the electric field generating circuit; wherein the control circuitry causes the electric field generating circuit to generate one or more electric fields having a field strength selected from a range of from 0.25 V/cm to 1000 V/cm; one or more supply wires in electrical communication with the electric field generating circuit, the one or more supply wires each in electrical communication with one or more supply electrodes, wherein one or more supply electrodes are configured to deliver an electric field at or near the site of the cancerous tumor; and one or more sensing wires in electrical communication with the control circuitry, the one or more sensing wires each in electrical communication with one or more sensing electrodes; and wherein the one or more sensing electrodes are configured to measure an impedance of the cancerous tumor at least two different electric field strengths; and wherein the control circuitry is configured to modulate the one or more electric fields if the impedance at or near the site of the cancerous tumor changes by at least 5 % during a therapy relative to an initial impedance at or near the site of the cancerous tumor at a beginning of the given therapy.