Antenna Coil Non-Active Detuning Detection in MRI Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic resonance tomography systems face safety hazards due to excessive field strengths during excitation pulses, particularly for patients with implants, as existing active and passive protection mechanisms can fail, leading to potential harm.
Innovation Solution
An apparatus with a transmitter, antenna, and controller that emits radio-frequency signals at varying amplitudes to detect non-active detuning in antenna coils, using an amplitude meter to assess induced voltages and currents, and comparing these to predetermined reference relationships to prevent damage and ensure patient safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protection mechanisms (PIN diodes, crossed diodes, or safety fuses) are used to prevent excessive field strengths, then patient safety is improved, but the system may still fail to detect defective protection mechanisms, leading to potential harm
Solution Approach 1:
The system performs preliminary detection before the excitation pulse by emitting test signals and measuring induced voltages in the antenna coil. This advance detection identifies defective protection mechanisms (PIN diodes, crossed diodes, or safety fuses) before they can fail during the actual excitation pulse, preventing excessive field strengths that would endanger patients with implants.
Solution Approach 2:
The system uses an amplitude meter to measure the induced voltage in the antenna coil during testing and feeds this information back to the controller. The controller compares the measured voltage against expected values to determine whether protection mechanisms are functioning properly, enabling real-time safety verification before patient examination.
2Power
If high power radio-frequency signals are used for excitation pulses, then imaging quality is improved, but excessive field strengths may be generated that endanger patients with implants
Solution Approach 1:
Before applying high power radio-frequency excitation pulses for imaging, the system performs preliminary safety testing by emitting low-power test signals and measuring induced voltages in the antenna coil. This advance check verifies that protection mechanisms are functional, allowing the system to safely proceed with high-power imaging or interrupt transmission if defects are detected, thereby preventing excessive field strengths that would endanger patients.
3Reliability
If active protection components (PIN diodes) are used for detuning, then coil protection is improved, but these components can fail leading to resonant conditions and excessive field strengths
Solution Approach 1:
The system performs preliminary detection before the excitation pulse by emitting test signals at the Larmor frequency and measuring induced voltages in the antenna coil using an amplitude meter. This advance testing identifies defective PIN diodes or other protection mechanism failures before they can cause harmful resonant conditions during high-power transmission, preventing excessive field strengths that would endanger patients with implants.
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
Effectively detects non-active detuning in antenna coils before damage occurs, ensuring patient safety by interrupting radio-frequency emissions when hazardous conditions are detected, thereby preventing excessive field strengths.
Implementation Method 1
The transmitter (24) is configured to emit radio frequency at the frequency of a Larmor frequency at which the antenna coil is configured to receive a magnetic resonance signal
Implementation Method 2
The controller has a signal connection with an amplitude meter and is configured to use the amplitude meter to acquire testing amplitudes as a function of the emitted signal
Data Source
AI summary
An apparatus and a method for detecting an antenna coil with a non-active detuning apparatus are provided. The apparatus has a transmitter, an antenna, an amplitude meter, and a controller. The controller actuates the transmitter such that the transmitter emits radio-frequency signals with different predetermined amplitudes via the antenna. The controller acquires testing amplitudes with the amplitude meter as a function of the emitted signal and determines a testing relationship between the predetermined amplitudes and the acquired testing amplitudes. If the determined testing relationship deviates from a predetermined reference relationship, a signal is output.