Movable RF Coil Elements for SAR Reduction
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Solution Overview
Problem
Conventional multi-channel RF coils have a fixed rigid frame structure, leading to local peak Specific Absorption Rate (SAR) issues and reduced degree of freedom in B1 shimming, which limits the performance improvement in magnetic field uniformization.
Innovation Solution
A radio frequency (RF) coil device with movable RF coil elements supported by a cylindrical support member, allowing for adjustable spacings and independent movement along the circumference and length, enabled by a driver and controller for power and phase control, and a probe for SAR prediction and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed rigid frame structure is used for multi-channel RF coils, then the structural stability is improved, but local peak SAR occurs and cannot be completely removed by B1 shimming
Solution Approach 1:
The patent applies the dynamics principle by making the RF coil elements movable rather than fixed. Each RF coil element can be independently positioned along the cylindrical support member, allowing the system to dynamically adjust its configuration. This mobility enables optimization of element positions to reduce local peak SAR while maintaining structural stability through the support member design.
2Object-affected harmful factors
If some elements of the RF coil are not used to reduce the local peak SAR, then the harmful factors are reduced, but the degree of freedom during B1 shimming is degraded
Solution Approach 1:
The patent applies segmentation by dividing the RF coil system into multiple independently positionable elements. Each element can be individually adjusted along the cylindrical support member, allowing selective optimization of element positions. This segmentation enables the system to maintain high degree of freedom for B1 shimming while reducing local peak SAR by strategically positioning elements away from high SAR regions.
3Adaptability or versatility
If the RF coil elements are made movable for position adjustment, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The patent applies universality through the cylindrical support member design that provides multiple functions: it supports all RF coil elements, enables their movement along the circumference, maintains structural stability, and facilitates position adjustment. This multi-functional design reduces overall device complexity compared to having separate mechanisms for each 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
The solution effectively reduces local peak SAR and enhances B1 shimming by allowing for precise adjustment of RF coil element positions, improving the uniformity of the magnetic field and reducing energy absorption by the human body.
Implementation Method 1
A radio frequency (RF) coil device includes a plurality of RF coil elements configured to generate an RF magnetic field
Implementation Method 2
enhances B1 shimming by allowing for precise adjustment of RF coil element positions, improving the uniformity of the magnetic field
Data Source
Figure 1
Figure 2~3
Figure 4A~4C
AI summary
A radio frequency (RF) coil for magnetic resonance includes a plurality of RF coil elements configured to generate an RF magnetic field, and a support member configured to support the plurality of RF coil elements so that at least one of the plurality of RF coil elements is movable.