MEG Shielding with OPMs and Active Coils
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Solution Overview
Problem
Existing magnetoencephalography (MEG) systems face challenges with bulky, expensive, and maintenance-intensive superconducting quantum interference devices (SQUIDs) and conventional optically pumped magnetometers (OPMs) that are not suitable for mobile or wearable applications due to requirements for cryogenic cooling and limited sensitivity in high ambient magnetic fields.
Innovation Solution
A shielding arrangement for MEG systems incorporating a passively shielded enclosure with passive magnetic shielding material and active shield coils, along with a wearable MEG device using optically pumped magnetometers (OPMs) and wearable active shield coils, to reduce ambient background magnetic fields, allowing for comfortable, manufacturable, and mobile magnetic field measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SQUIDs are used for MEG measurement, then measurement precision is improved, but device complexity and maintenance requirements increase due to cryogenic cooling requirements
Solution Approach 1:
The patent extracts the cryogenic cooling requirement from the MEG measurement system by replacing SQUIDs with OPMs that operate at room temperature. This removes the complex cryogenic infrastructure while maintaining magnetic field measurement capability, directly resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent changes the operating temperature parameter of the magnetometer from cryogenic (SQUID) to room temperature (OPM). This parameter change enables mobile and wearable applications while maintaining measurement precision, resolving the contradiction between measurement quality and system complexity
2Measurement precision
If passive magnetic shielding material is added to reduce ambient magnetic fields, then measurement precision is improved, but weight and volume of the system increase
Solution Approach 1:
The patent introduces active shield coils as an intermediary component that generates compensating magnetic fields to cancel ambient interference. This active shielding approach replaces or supplements passive magnetic shielding material, reducing weight while maintaining measurement precision through electromagnetic compensation
Solution Approach 2:
The patent replaces the mechanical/passive magnetic shielding material with an active electromagnetic shielding system using OPMs and control algorithms. This substitution reduces physical weight and volume while maintaining or improving measurement precision through real-time magnetic field compensation
3Device complexity
If conventional OPMs are used without active shielding, then device complexity is reduced, but measurement precision deteriorates in high ambient magnetic fields
Solution Approach 1:
The patent makes the OPM system multi-functional by integrating both measurement and active shielding capabilities into a single wearable device. The OPM serves dual purposes: measuring neural magnetic fields and detecting ambient interference for compensation, eliminating the need for separate shielding systems while improving measurement precision
Solution Approach 2:
The patent implements feedback control where OPMs continuously monitor ambient magnetic fields and the system dynamically adjusts compensation fields in real-time. This feedback mechanism maintains high measurement precision in varying ambient conditions without requiring complex passive shielding structures
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 enables high-fidelity neural recordings with dense full head coverage, improved user comfort, and manufacturability, facilitating population-scale studies by effectively attenuating ambient background magnetic fields and allowing for user movement within a magnetically shielded environment.
Implementation Method 1
each of the plurality of walls including passive magnetic shielding material to reduce an ambient background magnetic field within the passively shielded enclosure
Implementation Method 2
active shield coils distributed within the passively shielded enclosure and configured to further reduce the ambient background magnetic field within the user area
Implementation Method 3
wearable MEG measurement device including optically pumped magnetometers (OPMs)
Data Source
AI summary
A shielding arrangement for a magnetoencephalography (MEG) system includes a passively shielded enclosure having a plurality of walls defining the passively shielded enclosure, each of the plurality of walls including passive magnetic shielding material to reduce an ambient background magnetic field within the passively shielded enclosure; a vestibular wall extending from a first vertical wall to define, and at least partially separate, a vestibular area of the passively shielded enclosure adjacent the doorway and a user area of the passively shielded enclosure; and active shield coils distributed within the passively shielded enclosure and configured to further reduce the ambient background magnetic field within the user area of the passively shielded enclosure.