Dual-Frequency Electric Field Resonator for MRI Heating Tests
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Solution Overview
Problem
Current methods for testing RF-induced heating in medical devices during MRI procedures are inefficient, requiring large RF coils and shielded rooms, and suffer from uncertainties due to non-uniform electric fields and precise device positioning, limiting the effectiveness and practicality of the tests.
Innovation Solution
An electric field generator system is developed, comprising a rectangular resonator with a four-way feeding network, capable of generating uniform electric fields at 64 MHz and 128 MHz, allowing for compact, efficient, and accurate RF-induced heating tests by simulating the electric field distributions along orthogonal pathways, thereby reducing uncertainty and integrating 1.5T and 3T tests into a single system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large RF coils and shielded rooms are used for testing, then the testing coverage and field strength are improved, but the device complexity and testing cost increase
Solution Approach 1:
The patent combines multiple test frequencies (64 MHz and 128 MHz) into a single resonator system, eliminating the need for separate large RF coils for each frequency. The four-way feeding network integrates multiple signal paths into one unified device, reducing overall system complexity while maintaining comprehensive testing capability.
Solution Approach 2:
The resonator is designed to serve multiple functions: it can operate at both 64 MHz and 128 MHz frequencies, support four different feeding configurations, and test various medical device orientations within a single device. This multi-functionality replaces what would traditionally require multiple specialized large-scale testing systems.
2Device complexity
If non-uniform electric fields are used in testing, then the testing setup is simpler, but the measurement precision and reliability decrease due to uncertainties
Solution Approach 1:
The patent creates locally uniform electric fields within specific regions of the resonator by strategically placing feeding points and using orthogonal pathways. This local uniformity ensures precise measurements in the critical test zones without requiring the entire resonator structure to be uniformly configured, balancing simplicity with precision.
Solution Approach 2:
The system dynamically changes field distribution parameters by switching between different feeding configurations (four-way feeding network) and operating frequencies. This allows optimization of field uniformity for different test scenarios, improving measurement precision while maintaining system simplicity through parameter adjustment rather than structural complexity.
3Measurement precision
If precise device positioning is required for accurate testing, then the measurement precision is improved, but the ease of operation and productivity decrease
Solution Approach 1:
The resonator is designed with orthogonal pathways that create equipotential regions where device positioning is less critical. By distributing feeding points symmetrically and creating uniform field zones, the system reduces sensitivity to exact device placement, allowing operators to achieve accurate results without requiring micrometer-level positioning precision.
Solution Approach 2:
The system uses four feeding points that provide redundant field coverage, ensuring that even if device positioning is not perfectly precise, at least one feeding configuration will provide adequate field overlap and measurement accuracy. This excessive action approach compensates for positioning tolerances while maintaining operational simplicity.
4Measurement precision
If separate testing systems are used for different frequencies, then the measurement precision for each frequency is improved, but the productivity and time efficiency decrease
Solution Approach 1:
The patent merges 64 MHz and 128 MHz testing capabilities into a single resonator system with a four-way feeding network. This allows sequential or comparative testing of medical devices at both frequencies without physical system changes, dramatically improving productivity while maintaining the measurement precision that would result from dedicated frequency-specific systems.
Solution Approach 2:
The resonator serves as a universal testing platform that can operate at multiple frequencies and support various test configurations. This multi-functionality enables comprehensive multi-frequency testing in one system, eliminating the time required to physically reconfigure or replace separate testing systems for different frequencies.
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
The system provides highly correlated results for RF-induced heating tests across different frequencies, reduces sensitivity to device positioning errors, and offers a cost-effective, compact solution for evaluating RF-induced heating in medical devices, improving the accuracy and efficiency of MRI safety assessments.
Implementation Method 1
A dual-frequency high electric field generator for magnetic resonance imaging (MRI) safety testing of passive implantable medical devices... capable of generating uniform electric fields at 64 MHz and 128 MHz
Implementation Method 2
generating a uniform electric field within the electric field generator, such that the uniform electric field induces RF-heating within the medical device
Data Source
AI summary
In an embodiment, the present disclosure pertains to electric field generators that include a signal generator electrically connected to a power amplifier, a impedance matching circuit electrically connected to the power amplifier, and a power divider electrically connected to the impedance matching circuit and to at least one of a first wall, a second wall, a third wall, a fourth wall, or a base area. In an additional embodiment, the present disclosure pertains to method of determining radio frequency (RF)-induced heating on a medical device utilizing an electric field generator of the present disclosure. Additional embodiments of the present disclosure pertain to methods of making electric field generators for testing a medical device.