Inductive Power Transfer for MRI Sensor Coils
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Solution Overview
Problem
Current nuclear magnetic resonance imaging (MRI) systems face issues with unwanted disturbances in the RF range due to the sensitivity of sensor coils, which can lead to image quality deterioration and potential harm to patients, particularly when using cables for power transmission.
Innovation Solution
The implementation of an inductive power transfer system that operates at a frequency outside the receiver coil's RF band, using higher harmonics that flank the receiver coil's frequency range to avoid disturbances, allowing for wireless power supply to MRI components without interfering with signal acquisition, and incorporating energy storage for continuous power during signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cables are used to connect sensor coils to the MRI system, then power and signals can be transmitted, but unwanted disturbances occur in the RF range causing image quality deterioration and potential harm to patients
Solution Approach 1:
The patent removes cables from the system entirely, extracting the harmful element that causes RF disturbances. Instead of using cable-connected sensor coils, the invention employs wirelessly powered sensor coils that are electrically isolated from the MRI system, thereby eliminating the source of common mode currents and RF interference while maintaining functional connectivity through wireless power and data transmission
Solution Approach 2:
The patent introduces an intermediary wireless power transmission system using magnetic induction. Transmitter coils integrated in the MRI tube generate an alternating magnetic field that induces voltage in power receiver coils integrated in the sensor coil module, enabling power transfer without direct electrical connection. This intermediary magnetic field coupling serves as a mediator that transfers energy without the harmful effects of cable-based electrical connections
2Object-affected harmful factors
If wireless power supply is implemented using magnetic induction, then cables are eliminated and patient safety is improved, but unwanted disturbances may occur in the sensor coils due to RF sensitivity
Solution Approach 1:
The patent applies local quality by making the power transmission frequency specific and localized to a range that does not interfere with the sensor coil's operational RF band. The transmitter coils operate at a predetermined frequency specifically chosen to be outside the sensitive reception frequency range of the sensor coils, creating a localized frequency domain for power transmission that does not overlap with the sensing domain
Solution Approach 2:
The patent converts the potential harm of electromagnetic interference into a benefit by carefully selecting the power transmission frequency to flank the receiver coil frequency range. The higher harmonics of the power transmission frequency are positioned to border the RF band without entering it, effectively using the frequency spectrum structure to create beneficial separation between power transmission and signal reception zones
3Power
If power transmission frequency is set within the receiver coil frequency range, then efficient power transfer is achieved, but disturbances occur during MRI signal acquisition
Solution Approach 1:
The patent employs periodic action by operating the power transmission system at a specific frequency that is periodically applied but deliberately chosen to be outside the signal acquisition frequency band. The transmitter coils generate alternating magnetic fields at a predetermined frequency that periodically transfers power to the sensor coil module without coinciding with the periodic signal acquisition cycles, thereby maintaining both power supply and signal integrity
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 prevents disturbances during MRI signal acquisition, enhances image quality, and eliminates the need for cables, ensuring safe and efficient power delivery to MRI components, including sensors and other devices, while maintaining the integrity of the imaging process.
Implementation Method 1
The power is transmitted by magnetic induction. Transmitter coils, which are integrated in the MRI tube, generate an alternating magnetic field. The power receiver coils are integrated in the sensor coil module. The alternating magnetic field induces a voltage in the power receiver coil
Implementation Method 2
The alternating magnetic field induces a voltage in the power receiver coil, which is used to power the module
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The invention relates to a nuclear magnetic resonance imaging apparatus comprising: a main magnet (122) adapted for generating a main magnetic field; at least one radio frequency receiver coil unit (144) for acquiring magnetic resonance signals in a receiver coil radio frequency band (202) from an examined object (124); means (140) for inductively (wirelessly) supplying electric power to an electric component of the apparatus, wherein the electric component is adapted to be powered by inductively supplied electric power, wherein the power transfer frequency (200) and the higher-harmonics (206) of the power transfer frequency (200) for inductively supplying the electric power are located outside the receiver coil radio frequency band (202).