Magnetic Shielding Mechanism for MRI Aperture Safety
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Solution Overview
Problem
MRI systems with strong static magnetic fields pose a risk of attracting metal objects, which can be dangerous to patients and difficult to remove, and existing shielding methods do not fully address the issue of preventing metallic objects from entering the magnetic fringe field.
Innovation Solution
A magnetic shielding mechanism (MSM) comprising a ring-shaped array of magnets positioned outside the MRI device's aperture, with a magnetic field strength greater than the fringing field, to safely attract and prevent metallic objects from entering the MRI bore, and includes a connection to a gantry or patient bed for enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive shielding (thick metal walls) or active shielding (electromagnet systems) is applied to reduce the magnetic fringe field, then the extent of the magnetic fringe field is reduced, but the complexity and cost of the shielding system increases
Solution Approach 1:
A magnetic shielding member (MSM) is introduced as an intermediary component positioned between the MRI device and the surrounding environment. This MSM acts as a mediator that creates a controlled magnetic field to attract metallic objects away from the MRI bore, thereby reducing the harmful effects of the fringe field without requiring complex passive or active shielding systems throughout the entire MRI housing.
Solution Approach 2:
Instead of applying uniform shielding throughout the entire MRI system, the invention applies magnetic shielding locally at the aperture region where metallic objects are most likely to enter. The MSM is positioned specifically at the opening to create a localized magnetic field that safely attracts metal objects, providing targeted protection without the need for comprehensive system-wide shielding.
2Measurement precision
If the MRI static magnetic field strength is increased to improve imaging quality, then the imaging capability is enhanced, but the risk of attracting metal objects and the extent of the fringe field increases
Solution Approach 1:
The invention converts the harmful magnetic attraction force into a beneficial safety feature. The MSM uses the same magnetic field principle that causes the hazard to instead attract metallic objects toward a safe location away from the patient and MRI bore. By positioning the MSM with appropriate polarity and strength, the potentially dangerous magnetic force is transformed into a protective mechanism that actively prevents metal objects from entering the hazardous zone.
3Productivity
If metal objects are allowed to enter the MRI bore, then the imaging procedure can proceed, but the metal objects can become difficult to remove and pose physical danger to the patient
Solution Approach 1:
The magnetic shielding member performs preliminary action by attracting and capturing metallic objects before they can enter the MRI bore and reach the patient. By positioning the MSM at the aperture, it creates a preliminary barrier that intercepts metal objects early in their potential trajectory, preventing them from reaching the hazardous zone where they would be difficult to remove and dangerous to the patient.
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
Effectively reduces the risk of metallic objects entering the MRI bore by creating a stronger magnetic field outside the device, safely attracting them away from the patient and reducing the magnetic fringe field's extent, thereby enhancing patient safety and preventing dangerous attractions.
Implementation Method 1
the MSM comprising at least one magnet with a magnetic field BMSM; the MSM is affixed at a distance LMSM from the MRD's aperture; wherein at any distance L, BMSM>>BF/L
Data Source
AI summary
A magnetic shielding mechanism for preventing penetration of metallic objects through an aperture, towards the open bore of an magnetic resonance imaging device, where the magnetic field is maximized. The magnetic resonance imaging device produces a fringing magnetic field that decreases with increasing distance (L) from the aperture. The mechanism includes at least one magnet with a magnetic field. The mechanism is affixed at a distance from the aperture of magnetic resonance imaging device.