RF Shield Conductive Coating Eddy Current Suppression MRI
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Solution Overview
Problem
Magnetic resonance imaging systems face a challenge in designing RF shields that effectively block RF signals while minimizing Eddy current-induced heat dissipation, as highly conductive materials used for RF shielding can induce unwanted Eddy currents, leading to increased production costs due to the need for slitted screens and bridging capacitors.
Innovation Solution
A magnetic resonance imaging system utilizing a conductive coating as the RF shield material, which eliminates the need for slitting and bridging capacitors, allowing for easier and cheaper manufacturing, and incorporates direct thermal contact with the gradient coil cooling system for efficient heat dissipation, thereby reducing production costs and improving RF shielding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly conductive materials are used for RF shielding, then RF screening performance is improved, but Eddy current-induced heat dissipation increases
Solution Approach 1:
The patent applies parameter changes by modifying the electrical conductivity of the RF shield material. Instead of using highly conductive materials, the invention uses materials with optimized, moderate conductivity levels that provide sufficient RF shielding while minimizing Eddy current generation. This parameter optimization resolves the contradiction between RF screening effectiveness and heat dissipation.
Solution Approach 2:
The patent employs composite materials combining electrically insulating substrate material with conductive coating material. This composite structure provides RF shielding functionality while the insulating base material suppresses Eddy current formation, thus resolving the contradiction between achieving good RF screening and minimizing energy loss through Eddy currents.
2Loss of energy
If slitted RF-screens with bridging capacitors are used, then Eddy current suppression is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the complex slitting and capacitor bridging structures from the RF shield design. By using solid, continuous sheets of optimized material, the invention removes the need for precision slitting operations and capacitor assembly, thereby significantly reducing manufacturing complexity while maintaining Eddy current suppression through material selection.
Solution Approach 2:
The patent adopts simpler, more cost-effective solid sheet materials that can be manufactured and installed more easily than complex slitted structures with capacitors. This approach reduces both manufacturing cost and complexity while achieving the necessary Eddy current suppression through proper material selection rather than complex structural design.
3Loss of energy
If slitted RF-screens with bridging capacitors are used, then Eddy current suppression is improved, but production cost increases
Solution Approach 1:
The patent removes the expensive slitting and capacitor bridging processes from the manufacturing workflow. By using solid sheets of optimized conductivity material, the invention eliminates these complex manufacturing steps, thereby reducing production costs while maintaining effective Eddy current suppression through material property optimization.
Solution Approach 2:
The patent employs simpler, more affordable solid sheet materials that are easier and cheaper to manufacture than complex slitted structures requiring capacitor assembly. This material substitution reduces production costs significantly while achieving the same Eddy current suppression effect through proper material selection.
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 conductive coating provides effective RF shielding and Eddy current suppression, reducing production costs and heat dissipation, while maintaining high RF screening properties, and allows for a more efficient and larger examination volume without the need for additional cooling systems.
Implementation Method 1
a shielding material adapted for suppressing Eddy currents induced in the shield by said gradient magnetic fields
Implementation Method 2
for screening RF fields towards the gradient coils, said RF fields being generated by the RF antenna
Implementation Method 3
incorporates direct thermal contact with the gradient coil cooling system for efficient heat dissipation
Data Source
AI summary
The invention relates to a magnetic resonance imaging system (1) comprising: a main magnet (2) for generating a uniform, steady magnetic field within an examination volume, at least one RF antenna (9) for transmitting RF pulses to the examination volume for magnetic resonance spin excitation, a gradient coil unit comprising gradient coils (4, 5, 6) for generating gradient magnetic fields in the examination volume (100), an RF shield (104) disposed between said RF antenna (9) and said gradient coils (4, 5, 6), said RF shield (104) comprising a shielding material adapted for suppressing Eddy currents induced in the shield by said gradient magnetic fields and for screening RF fields towards the gradient coils (4, 5, 6), said RF fields being generated by the RF antenna (9), wherein the RF shield comprises a conductive coating (104, 110) as shielding material.