Toroidal MRI Magnet Segmentation for Stray Field Reduction
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Solution Overview
Problem
Traditional MRI scanners face challenges due to extensive stray magnetic fields, claustrophobic patient experiences, and restricted access for medical staff, which limit their effectiveness and safety, particularly in interventional procedures. Additionally, the high cost and reduced efficiency of actively shielded magnets exacerbate these issues.
Innovation Solution
A toroidal MRI system design featuring multiple spatially separated magnet segments generating a segmented magnetic field with defined directions, forming a toroidal shape, which reduces stray fields and allows for open, angular imaging regions, enabling more comfortable and accessible imaging for patients and easier access for medical staff, while eliminating the need for active shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a solenoidal super-conducting magnet is used to generate the basic magnetic field, then the magnetic field strength and imaging quality are improved, but extensive stray magnetic fields are generated causing safety hazards and requiring large controlled areas
Solution Approach 1:
The magnet system is divided into multiple spatially separated magnet segments instead of a single solenoidal magnet. Each segment generates a portion of the basic magnetic field, and the segments are arranged to form a toroidal configuration. This segmentation reduces the stray magnetic field while maintaining the required field strength for imaging.
Solution Approach 2:
The magnet arrangement transitions from a linear solenoidal configuration to a toroidal (circular) configuration in a different spatial dimension. The magnet segments are positioned around a central axis with their magnetic field directions oriented at angles to each other, creating a closed-loop magnetic field path that confines the field more effectively and reduces stray fields.
2Object-affected harmful factors
If actively shielded magnets are used to reduce stray fields, then the stray magnetic field strength is reduced, but the cost increases and the efficiency of the basic magnetic field decreases
Solution Approach 1:
The magnet segments themselves generate the basic magnetic field efficiently without requiring separate active shielding coils. The toroidal arrangement of the magnet segments inherently confines the magnetic field, making the system self-shielding. This eliminates the need for additional expensive shielding components while maintaining field efficiency.
3Strength
If a solenoidal magnet with a narrow bore is used, then the magnetic field is concentrated, but patient accessibility is restricted and claustrophobia is increased
Solution Approach 1:
The imaging space is segmented into multiple angular regions between the magnet segments, creating open imaging regions rather than a single narrow bore. This allows patients to be positioned in open spaces while still receiving the required magnetic field for imaging, improving accessibility and reducing claustrophobia.
Solution Approach 2:
The imaging region transitions from a linear narrow bore to an angular open space between magnet segments. The toroidal configuration creates multiple open imaging regions where patients can be positioned with better access, eliminating the confined tunnel experience of traditional solenoidal scanners.
4Power
If a solenoidal magnet design is used, then the basic magnetic field is generated effectively, but the access for medical staff to the patient is severely restricted during imaging
Solution Approach 1:
The magnet system is segmented into multiple sections with open regions between them, allowing medical staff to access patients from multiple directions during imaging procedures. The angular arrangement of magnet segments creates corridors and access points that maintain field efficiency while improving accessibility for interventional procedures.
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 toroidal MRI system minimizes stray magnetic fields, enhances imaging accessibility, reduces costs, and improves patient comfort, allowing for compact installation and simultaneous scanning of multiple patients, thereby increasing efficiency and reducing claustrophobic stress.
Implementation Method 1
A toroidal MRI system design featuring multiple spatially separated magnet segments generating a segmented magnetic field with defined directions, forming a toroidal shape
Data Source
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AI summary
The invention describes a magnetic resonance imaging system (1) comprising a basic field magnetic arrangement (40) for generating a main magnetic field (B0) and a number of spatially separated imaging regions (IR1, IR2, IR3, IR4, IR5, IR6), wherein the basic field magnetic arrangement (40) comprises several spatially separated magnet segments (44), in order to generate segment magnetic fields with a defined segment field direction (R0), wherein at least two of the spatially separated magnet segments (44) are configured in a way that their defined segment field directions (R0) are running in an angular fashion to each other so that the segment magnetic fields result in a main magnetic field (B0) which has the form of toroid, wherein the magnetic resonance imaging system (1) is designed to be adapted to MR imaging of dedicated body or organ parts of a patient (O). The invention further describes a method for controlling an MRI system.