Multi-layered Sensor Housing with Staggered Slits for MR-PET Shielding
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Solution Overview
Problem
Conventional shielding housings for PET detection units in MR-PET scanners cause significant eddy currents and heat generation in varying magnetic fields, interfering with MR imaging performance.
Innovation Solution
A multi-layered housing structure with staggered slits in metallic layers is used to reduce eddy currents and improve RF shielding, comprising a substrate with overlapping metallic layers, including gold, silver, or copper, and an optional electric insulation layer, designed to minimize electromagnetic wave leakage and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional shielding housing with copper foil or metallic material is used to shield PET detection units from RF fields, then RF shielding performance is improved, but eddy currents are generated in the varying magnetic field causing interference with MR imaging and heat generation
Solution Approach 1:
The continuous metallic shielding layer is segmented into multiple discrete metallic layers with gaps between them. Each metallic layer is further divided into multiple metallic segments separated by non-conductive gaps. This segmentation breaks the continuous conductive path that would otherwise generate eddy currents, while still maintaining RF shielding through multiple reflected and absorbed electromagnetic waves.
Solution Approach 2:
Different regions of the shielding structure have different properties: metallic layers provide RF shielding in regions exposed to RF fields, while non-conductive gaps and non-metallic material regions prevent eddy current formation in regions exposed to varying magnetic fields. The shielding structure transitions from uniform metallic material to a composite structure with spatially varying conductivity.
2Object-affected harmful factors
If continuous metallic shielding layers are used to block RF fields, then RF shielding effectiveness is improved, but electromagnetic wave leakage increases through continuous paths
Solution Approach 1:
The shielding structure uses multiple discrete metallic layers separated by non-conductive gaps. Each layer is segmented into multiple metallic segments. This creates a stepped shielding effect where electromagnetic waves must pass through multiple interfaces and gaps, significantly reducing leakage while preventing continuous conductive paths.
Solution Approach 2:
The shielding approach transitions from a two-dimensional continuous metallic sheet to a three-dimensional multi-layered structure with gaps in both the layer planes and within each layer. This adds dimensional complexity that blocks electromagnetic wave propagation paths more effectively.
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 solution effectively reduces eddy currents and heat generation, enhancing the performance of MR-PET scanners by minimizing interference from RF fields and maintaining the integrity of magnetic fields, thereby improving imaging quality and extending equipment lifespan.
Implementation Method 1
a shielding housing may be set to enclose one or more of the PET detection units to shield them from the RF field
Implementation Method 2
the copper foil or the other metallic material adopted may cause a remarkable amount of eddy currents on the walls of the housing
Implementation Method 3
the varying magnetic field and a varying radio frequency (RF) field caused by the components for MR imaging
Data Source
AI summary
A housing for shielding a sensor from a radiofrequency field and an imaging system including the same are provided in the present disclosure. The imaging system may include a magnetic resonance imaging (MRI) device. The housing may include a plurality of walls forming at least a part of a cavity for accommodating a sensor of the imaging system. At least one of the plurality of walls may include a substrate and a multi-layered structure disposed on the substrate. The multi-layered structure may include a plurality of metallic layers. At least one pair of adjacent layers of the plurality of metallic layers may include slits. The slits of the at least one pair of adjacent layers may be staggered.