Failsafe Switch for MRI RF Coil Induced Current Protection
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Solution Overview
Problem
Magnetic resonance imaging (MRI) RF coil assemblies with transmit functionality lack built-in protection against induced RF currents when not connected, risking damage and safety hazards due to excessive heating during MRI procedures.
Innovation Solution
Incorporating an electrically-controlled switch with variable impedance that changes in response to a control current, allowing unimpeded RF current passage during connection and impeding induced currents when disconnected, thereby providing failsafe protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the RF coil assembly is left unconnected during MRI procedures, then the coil assembly remains available for potential use, but induced RF currents cause excessive heating and damage
Solution Approach 1:
The patent applies preliminary action by incorporating a failsafe switch that is pre-configured to detect the connected/unconnected state of the RF coil assembly. Before RF transmission occurs, the switch automatically detects whether the coil is properly connected to the MRI system and preemptively prevents induced RF currents from causing excessive heating by opening the circuit when disconnected, thus protecting the coil assembly before damage can occur.
2Reliability
If a protective switch is added to the RF coil assembly, then induced RF currents are blocked when disconnected, but the device complexity increases
Solution Approach 1:
The patent applies self-service by designing a failsafe switch that automatically detects whether the RF coil assembly is connected to the MRI system and autonomously opens or closes the circuit without requiring external control. The switch monitors its own operational state and self-regulates the RF current path based on connection status, eliminating the need for additional control systems or manual intervention while providing reliable protection against induced RF currents.
3Productivity
If the RF coil assembly is designed for immediate reuse after disconnection, then productivity is maintained, but damage from induced currents requires component replacement
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a failsafe switch that prevents induced RF currents from causing damage in the first place. By automatically opening the circuit when the coil assembly is disconnected, the switch cushions the coil components from excessive heating and RF-induced damage before it can occur, ensuring the assembly remains intact and ready for immediate reuse without requiring any component replacement or repair.
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
Prevents damage to the RF coil assembly and ensures safety by significantly reducing induced RF currents, allowing for immediate reuse without component replacement and minimizing heat generation and burn risks.
Implementation Method 1
an electrically-controlled switch with variable impedance that changes in response to a control current
Implementation Method 2
induced RF currents may be caused to flow within various components of the RF coil assembly
Data Source
AI summary
An electrically-controlled failsafe switch is included in an MRI transmit-and-receive RF coil assembly so as to protect it from induced RF currents in the event it is disconnected from an MRI system, but inadvertently left linked to strong MRI RF fields during imaging procedures using other RF coils.