RF Receiver Detune Circuit Diode Fault Detection
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Solution Overview
Problem
Existing radio frequency (RF) receiver systems in magnetic resonance imaging (MRI) face safety concerns due to the risk of coils remaining resonant during transmission, leading to potential harm to patients and equipment. Additionally, current methods for ensuring coil safety, such as using fuses or crossed PIN-diode switches, are either ineffective or inefficient, causing image artifacts and requiring additional space.
Innovation Solution
A radio frequency (RF) receiver system that incorporates a detune circuit with a pair of crossed PIN diodes, which measures electrical detune direct current to determine the proper function of the PIN diodes. This system alternates detune voltage polarity with each RF pulse to detect faulty diodes and ensures the coil is safely detuned, eliminating the need for additional fuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fuse is used to ensure patient safety in unplugged coil situations, then patient safety is improved, but significant SNR losses occur and additional space is required
Solution Approach 1:
The patent changes the operational parameters of the detune circuit by measuring DC current at different polarities to detect diode functionality. This allows the system to maintain safety without the energy-dissipating fuse, preserving SNR while ensuring patient protection through active monitoring of the detune circuit's operational state
Solution Approach 2:
The detune circuit performs self-diagnosis by measuring its own DC current characteristics at different polarities. This self-monitoring capability enables the system to detect failures and alert operators without requiring external protective components like fuses, thereby eliminating SNR losses while maintaining safety
2Reliability
If a fuse is used to ensure patient safety, then patient safety is improved, but additional space is demanded which is problematic in modern flexible coil arrays
Solution Approach 1:
The patent extracts the safety function from the physical fuse component and relocates it to the control system through DC current measurement and polarity switching. This eliminates the need for additional physical space in the coil array while maintaining patient safety through electronic monitoring and detection of detune circuit failures
Solution Approach 2:
The mechanical fuse is replaced with an electronic monitoring system that measures DC current characteristics. This substitution eliminates the need for physical protective components in the coil structure, preserving the compact design of modern flexible coil arrays while providing equivalent or superior safety through active detection
3Ease of operation
If crossed PIN-diode switches are used to detune the coil, then coil detuning is achieved, but the system can fail if PIN diodes are broken, reacting similar to an open circuit
Solution Approach 1:
The patent implements feedback by measuring the DC current through the PIN diodes at different polarities. This feedback mechanism allows the system to monitor the health of the detune circuit components and detect failures, enabling operators to identify and replace faulty diodes before they compromise patient safety or image quality
4Reliability
If traditional fuses are used for protection, then patient safety is ensured, but response time is too slow for modern high channel count flexible coil arrays
Solution Approach 1:
The system performs preliminary detection of detune circuit functionality by measuring DC current characteristics before MRI scans begin. This preliminary action identifies potential failures in advance, allowing the system to alert operators and prevent unsafe operation without requiring fast-response protective components during the actual scanning process
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 proposed RF receiver system ensures safe operation by detecting and preventing faulty PIN diodes from causing unsafe coil resonance, thereby enhancing patient safety and reducing the risk of image artifacts. The system's ability to operate without additional fuses also addresses space constraints and efficiency losses in modern flexible coil arrays.
Implementation Method 1
The switching element is made by a self-biasing crossed pair of diodes, which are fed via an induced current from the transmitting body coil
Implementation Method 2
the interface is configured to measure an electrical current in the detune circuit to determine the proper function of the PIN diodes by measuring the detune direct current for a first detune voltage polarity and for a second reversed detune voltage polarity
Implementation Method 3
The coil detune circuit is in almost all applications made by a tank circuit using an inductor switched in parallel to a resonance capacitor
Implementation Method 4
the switching element is made by a self-biasing crossed pair of diodes, which are fed via an induced current from the transmitting body coil
Data Source
AI summary
For a radio frequency (RF) receiver system a solution for a safe operation of the radio frequency (RF) receiver system in magnetic resonance imaging shall be ensured. This is achieved by a radio frequency (RF) receiver system for use in a magnetic resonance (MR) imaging system the RF receiver system, wherein the RF receiver system comprises at least one RF receive coil with at least one detune circuit (1). The detune circuit (1) comprises at least a pair of crossed diodes (D1, D2) with an interface, wherein the interface is configured to measure an electrical current in the detune circuit (1) to determine the proper function of the PIN diodes (D1, D2) by measuring the detune direct current for a first detune voltage polarity and for a second reversed detune voltage polarity. The present invention also provides a magnetic resonance (MR) imaging system, a method for ensuring a safe radio frequency (RF) receiver system operation in magnetic resonance imaging, a software package for a magnetic resonance (MR) imaging system, a software package for upgrading a magnetic resonance (MR) imaging system and a computer program product.