Permanent Magnet Array for Portable MRI Using Genetic Algorithm Optimization
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Solution Overview
Problem
Conventional portable MRI systems using permanent magnet arrays struggle to generate sufficient magnetic fields with desired homogeneity and strength for imaging parts of the human body, such as the head, due to limitations in field strength and homogeneity, leading to suboptimal imaging quality.
Innovation Solution
A method and system for forming a permanent magnet system using an array of magnet ring pairs, where the geometrical parameters are optimized using a genetic algorithm to achieve a magnetic field with an average field strength of 150 mT or more and field homogeneity of 50,000 ppm or less in a longitudinal direction, and 100 mT or more with field homogeneity of 200,000 ppm or less and monotonicity in a transverse direction, within a specific field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional imaging approach is taken with Fourier transformation and linear gradient fields requiring a homogeneous B0 field, then imaging quality is improved, but the magnet array becomes bulky and cannot be scaled down to portable size
Solution Approach 1:
The patent changes the fundamental parameters of the magnetic field from homogeneous to non-homogeneous with specific monotonicity characteristics. The B0 field is designed to have a monotonic gradient in the transverse direction rather than being uniform, which enables portable scaling while maintaining imaging capability through modified reconstruction algorithms
Solution Approach 2:
The patent replaces the traditional mechanical approach of achieving homogeneous fields with large magnet arrays with a computational approach. Non-linear gradient fields and monotonic B0 fields are used in conjunction with modified image reconstruction algorithms (such as O-space imaging or parallel imaging techniques) to substitute for the traditional Fourier transformation method that requires homogeneous fields
2Volume of moving object
If the magnet array is scaled down to a portable size, then portability is improved, but the imaging volume becomes too small to image a human organ
Solution Approach 1:
The patent extends the imaging capability from two-dimensional surface imaging to three-dimensional volumetric imaging by designing a magnet array configuration that produces a monotonic magnetic field in the transverse direction. This dimensional extension allows the portable magnet array to image entire human organs such as the head while maintaining compact size
Solution Approach 2:
The patent changes the magnetic field parameters to achieve monotonicity in the transverse direction with controlled gradients. This parameter change enables the portable magnet array to generate sufficient field variation across a larger imaging volume while maintaining the compact form factor needed for portability
3Ease of operation
If conventional permanent magnet arrays are used, then portability and low cost are improved, but field strength and homogeneity are insufficient for high-quality imaging
Solution Approach 1:
The patent changes the magnetic field parameters to achieve monotonicity in the transverse direction with specific gradient characteristics. By controlling the field strength (100-300 mT) and establishing monotonic variation rather than homogeneity, the system achieves both portability and sufficient imaging quality
Solution Approach 2:
The patent substitutes the requirement for homogeneous magnetic fields with computational methods. Modified image reconstruction algorithms (such as O-space imaging, parallel imaging, or compressed sensing techniques) replace the traditional Fourier transformation approach, enabling high-quality imaging with non-homogeneous, monotonic magnetic fields from portable permanent magnet arrays
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 optimized permanent magnet system effectively generates a magnetic field suitable for imaging parts of the human body, improving field homogeneity by up to 80% while maintaining similar field strength, enabling high-quality imaging in a portable MRI system.
Implementation Method 1
forming the array of magnet ring pairs based on the determined one or more types of geometrical parameters, whereby the above-mentioned determining one or more types of geometrical parameters for forming the array of magnet ring pairs is based on a genetic algorithm
Data Source
AI summary
There is provided a method of forming a permanent magnet system, the method including: determining one or more types of geometrical parameters for forming an array of magnet ring pairs including a first subarray of first magnet rings and a second subarray of second magnet rings spaced apart from the first subarray of the first magnet rings along a longitudinal axis; and forming the array of magnet ring pairs based on the determined one or more types of geometrical parameters, whereby the above-mentioned determining one or more types of geometrical parameters for forming the array of magnet ring pairs is based on a genetic algorithm. There is also provided a corresponding permanent magnet system, such as formed by the method.