RF Line PCB Filters for MR Induced Currents
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Solution Overview
Problem
Current magnetic resonance (MR) systems face issues with high costs, labor-intensive production, and space constraints due to the use of coaxial cables and manual assembly of standing wave traps, which also lead to inefficiencies in signal transmission and potential patient safety risks from induced currents.
Innovation Solution
The implementation of radiofrequency lines using printed circuit board technology with frequency filters, eliminating the need for coaxial cables and allowing for automated production, reduces costs and space requirements while effectively blocking induced currents without impeding information-carrying signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coaxial cables are used to transmit radiofrequency signals through the B1 magnetic field, then signal transmission is achieved, but high currents are induced on the cable sheath causing patient safety risks and B1 field homogeneity destruction
Solution Approach 1:
The patent extracts the radiofrequency line from the traditional coaxial cable structure and repositions it to be routed through the B1 magnetic field homogeneity volume in a controlled manner. By taking out the cable from its conventional routing and placing it within the homogeneity volume with proper shielding and filtering, the harmful induced currents are eliminated while maintaining signal transmission functionality.
Solution Approach 2:
The patent introduces frequency filters as intermediary components along the radiofrequency line routed through the B1 magnetic field. These filters act as mediators that block induced currents at specific frequencies while allowing the information-carrying signals to pass through, thus resolving the contradiction between signal transmission and harmful current induction.
2Object-affected harmful factors
If standing wave traps are manually assembled to block induced currents, then current suppression is achieved, but production becomes labor-intensive and costly
Solution Approach 1:
The patent segments the radiofrequency line into multiple sections, with frequency filters (standing wave traps) strategically placed at specific intervals along the line. This segmentation allows the filters to be integrated into the cable assembly in a systematic manner, reducing manual assembly complexity while maintaining effective current suppression at multiple points along the signal path.
Solution Approach 2:
The patent changes the parameters of the standing wave traps by integrating frequency filters with specific resonant frequencies matched to the B1 field frequency. This parameter optimization allows the filters to be more effectively integrated into the radiofrequency line, improving their current-blocking performance while facilitating automated or semi-automated assembly processes.
3Object-affected harmful factors
If standing wave traps are installed to suppress currents, then current blocking is achieved, but device space requirements increase
Solution Approach 1:
The patent implements nested doll principle by placing frequency filters inside the coaxial cable structure itself. The filters are integrated within the cable's existing layers (inner conductor, dielectric, outer shield), effectively nesting the current-blocking components within the signal transmission medium. This eliminates the need for external filter housings and reduces overall space requirements.
Solution Approach 2:
The patent transitions from a one-dimensional cable routing approach to a multi-dimensional integration strategy by embedding frequency filters within the cable's cross-sectional structure. This dimensional change allows the filters to occupy space within the cable's existing volume rather than requiring additional external space, thus blocking currents without increasing overall device volume.
4Object-affected harmful factors
If frequency filters are integrated into radiofrequency lines, then induced currents are blocked, but signal transmission must be maintained
Solution Approach 1:
The patent applies parameter changes by designing frequency filters with resonant frequencies specifically matched to the B1 magnetic field frequency while ensuring their bandwidth and insertion loss characteristics preserve the information-carrying signals. The filters' electrical parameters (inductance, capacitance, resistance) are optimized to block induced currents at the resonant frequency while maintaining signal integrity for the modulated MR signals.
Solution Approach 2:
The frequency filters serve as intermediary components that selectively interact with different frequency components of the radiofrequency signals. They act as mediators that block the harmful induced currents at the B1 frequency while allowing the information-carrying MR signals (which are modulated at different frequencies) to pass through with minimal attenuation, thus resolving the contradiction between current blocking and signal transmission.
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 solution enables cost-effective, efficient, and safe transmission of radiofrequency signals in MR devices by using printed circuit boards with integrated frequency filters, reducing signal losses and assembly time, and minimizing space requirements, thereby improving the overall performance and safety of MR systems.
Implementation Method 1
at least one frequency filter for blocking a voltage induced by the B1 magnetic field
Data Source
AI summary
An MR device includes at least one body coil for generating a B1 magnetic field and at least one radiofrequency line routed through the B1 magnetic field. The at least one radiofrequency line has at least one frequency filter for blocking a voltage induced by the B1 magnetic field. At least one section of the radiofrequency line routed through the B1 magnetic field is embodied in printed circuit board technology on at least one printed circuit board, and information-carrying signals may be transmitted over the at least one radiofrequency line on a different frequency than the frequency of the voltage induced by the B1 magnetic field.