Artificially Structured Electromagnetic Unit Cells for SAR Reduction
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Solution Overview
Problem
Current magnetic resonant imaging and nuclear magnetic resonant devices face challenges in generating localized, high-intensity radiofrequency magnetic fields while minimizing electric field densities to reduce specific absorption rate (SAR) and improve patient safety and comfort.
Innovation Solution
An array of artificially structured electromagnetic unit cells, including metamaterials with specific inclusions, is configured to transform radiofrequency electromagnetic waves into localized radiofrequency magnetic fields, with counteracting electric fields to manage electric field intensities and optimize SAR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional methods are used to generate radiofrequency magnetic fields, then magnetic field intensity can be achieved, but electric field density becomes excessively high increasing SAR
Solution Approach 1:
The system divides the electromagnetic field generation into separate functional components: first unit cells generate the magnetic field while second unit cells generate counteracting electric fields. This segmentation allows independent control of magnetic and electric field components, enabling high magnetic field intensity while suppressing electric field density and SAR.
Solution Approach 2:
The second artificially structured electromagnetic unit cells are configured to transform incident radiofrequency electromagnetic waves into electric fields that counteract the non-vanishing electric fields generated by the first unit cells. This preliminary anti-action reduces electric field density before it can contribute to SAR, while preserving the magnetic field generation function.
2Measurement precision
If high magnetic field intensity is generated for imaging, then imaging quality improves, but patient safety and comfort deteriorate due to increased SAR
Solution Approach 1:
By separating magnetic field generation (first unit cells) from electric field cancellation (second unit cells), the system can optimize magnetic field intensity for imaging quality while independently controlling electric field levels to maintain patient safety and comfort within SAR limits.
Solution Approach 2:
The system changes the electromagnetic parameters by using artificially structured unit cells with specific geometries and materials that enable selective transformation of incident radiofrequency waves into desired magnetic field patterns while suppressing harmful electric field components, thus improving imaging quality without exceeding SAR thresholds.
3Device complexity
If traditional electromagnetic structures are used, then simple design is maintained, but independent control of magnetic and electric fields is not achieved
Solution Approach 1:
The system segments the electromagnetic unit cells into distinct first and second types with different functional configurations. This segmentation enables independent control of magnetic and electric field generation, providing adaptability and versatility while maintaining a relatively simple overall structure based on repeated unit cell patterns.
Solution Approach 2:
The artificially structured electromagnetic unit cells employ composite material structures combining different geometric configurations and materials properties. This allows the system to achieve independent control of magnetic and electric fields through the composite response of the unit cells to incident radiofrequency electromagnetic waves.
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 configuration enables the generation of high-intensity radiofrequency magnetic fields with reduced electric field densities, minimizing SAR and enhancing imaging quality and patient safety by independently controlling magnetic and electric fields.
Implementation Method 1
a first artificially structured electromagnetic unit cell configured to transform incident radiofrequency electromagnetic waves into a radiofrequency magnetic field B perpendicular to the plane of the assemblage
Implementation Method 2
a second artificially structured electromagnetic unit cell configured to transform the incident radiofrequency electromagnetic waves into an electric field E counteracting a non-vanishing electric field generated by the first artificially structured electromagnetic unit cell
Data Source
AI summary
Described embodiments include a system, apparatus, and method. An apparatus includes an assemblage of artificially structured electromagnetic unit cells. The assemblage of artificially structured electromagnetic unit cells includes a first artificially structured electromagnetic unit cell configured to transform incident radiofrequency electromagnetic waves into a radiofrequency magnetic field B perpendicular to the plane of the assemblage. The assemblage of artificially structured electromagnetic unit cells includes a second artificially structured electromagnetic unit cell configured to transform the incident radiofrequency electromagnetic waves into an electric field E counteracting a non-vanishing electric field component generated by the first artificially structured electromagnetic unit cell.