MRI RF Shielding via Cutoff Waveguide

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Solution Overview

Problem

Existing MRI systems require a dedicated RF shielding room to prevent electromagnetic interference, which is costly and limits flexibility in system placement and operation.

Innovation Solution

The MRI system employs localized RF shielding using a first shielding apparatus within the MRI device and a second shielding apparatus around the patient table, forming a cutoff waveguide that effectively blocks interfering electromagnetic signals without the need for a dedicated shielding room.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a dedicated RF shielding room is used to prevent electromagnetic interference, then electromagnetic shielding effectiveness is improved, but system cost and installation complexity increase

Engineering Contradiction:

Improveelectromagnetic interferenceVSAvoidshielding room structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent divides the RF shielding function into two separate shielding apparatuses: one integrated with the gradient coil apparatus and another with the patient table device. This segmentation eliminates the need for a complete dedicated shielding room while maintaining electromagnetic interference protection through localized shielding components that work together.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines the RF shielding function with existing structural components of the MRI system. The first shielding apparatus is integrated into the gradient coil apparatus, and the second shielding apparatus is integrated into the patient table device, merging multiple functions into unified structures rather than adding separate shielding room infrastructure.

Inventive Principle:

Principle #5Merging (Combining)

2Object-affected harmful factors

If a dedicated RF shielding room is constructed, then RF signal isolation is improved, but flexibility in system placement deteriorates

Engineering Contradiction:

ImproveRF signal interferenceVSAvoidsystem placement flexibility

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

By segmenting the shielding into two independent apparatuses that can be separately positioned and configured, the system gains flexibility in placement while maintaining RF signal isolation. The modular design allows the shielding components to be adapted to different installation environments without requiring a dedicated shielding room.

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If traditional RF shielding room is used, then electromagnetic isolation is improved, but cost increases

Engineering Contradiction:

Improveelectromagnetic couplingVSAvoidsystem cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent extracts the essential RF shielding function from the expensive dedicated shielding room structure and implements it through targeted shielding apparatuses positioned at critical interfaces. This extraction maintains electromagnetic isolation effectiveness while dramatically reducing the cost by eliminating the need for complete room-scale shielding infrastructure.

Inventive Principle:

Principle #2Taking out (Extraction)

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 achieves effective RF shielding at a significantly lower cost than traditional methods, allowing for flexible placement and operation of the MRI system while maintaining image quality by isolating RF signals from external interference.

Implementation Method 1

An RF shielding layer for electromagnetically isolating the gradient coil apparatus and the RF coil apparatus can be interposed therebetween in the MRI system so as to prevent electromagnetic coupling of the gradient coil apparatus and the RF coil apparatus

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

the first shielding apparatus is in electrical contact with the second shielding apparatus to form a cutoff waveguide around the table portion which is capable of cutting off radio frequency signals at frequencies below a second frequency

Methodology Applied

Scientific EffectElectromagnetic wave cutoff: Waveguide

Data Source

PatentUS12320877B2Magnetic resonance imaging system

Publication Date: 2025.06.03 SINO CANADIAN HEALTH ENGINEENING RESEARCH INSTITUTE (HEFEI) LTD

AI summary

The present application relates to a magnetic resonance imaging system comprising: a magnetic resonance imaging device comprising a cylindrical gradient coil apparatus, a radio frequency coil apparatus configured to transmit radio frequency signals at a first frequency, and a first shielding apparatus comprising a first shielding layer arranged radially between the gradient coil apparatus and the radio frequency coil apparatus; and a patient table device comprising a table portion configured for a patient to lie on it, and a second shielding apparatus arranged around at least a portion of the table portion, wherein when the magnetic resonance imaging device is engaged with the patient table device, the first shielding apparatus is in electrical contact with the second shielding apparatus to form a cutoff waveguide which is capable of cutting off radio frequency signals at frequencies below a second frequency, the second frequency being greater than the first frequency.