MRI Static Field Adjustment Structure With Axial-Radial Shim Stacking
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Solution Overview
Problem
Existing magnetic resonance imaging systems face challenges in adjusting the static magnetic field distribution outside the static field magnet due to structural restrictions on iron shims, limiting flexibility in field adjustments.
Innovation Solution
A static field adjustment apparatus comprising a plurality of holding members that hold magnetic members, stacked in the axial and radial directions of the magnet, to adjust the static magnetic field distribution, using non-metallic materials and spacers to enhance field uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If iron shims are used to adjust static magnetic field distribution, then field adjustment is achieved, but structural restrictions limit adjustment flexibility in space outside the magnet
Solution Approach 1:
The static field adjustment apparatus is divided into multiple holding members that can be independently positioned and adjusted. Each holding member can hold magnetic members at specific locations, allowing segmented adjustment of the magnetic field distribution without requiring complex integrated structures.
Solution Approach 2:
The holding members are arranged in multiple layers at different radial distances from the magnet center, creating a three-dimensional adjustment structure. This multi-layered arrangement enables field adjustment in spatial dimensions outside the traditional magnet structure, overcoming the limitation of planar iron shim placement.
2Manufacturing precision
If multiple holding members are stacked in axial and radial directions, then adjustment precision is improved, but device complexity increases
Solution Approach 1:
Multiple holding members are nested concentrically at different radial distances from the magnet, with each holding member fitting within the spatial envelope of the outer structure. This nested arrangement achieves precise multi-dimensional positioning without requiring excessively complex external support structures.
Solution Approach 2:
Each holding member serves multiple functions: it holds magnetic members, provides structural support, and acts as a positioning element for subsequent holding members. This multi-functionality reduces the need for separate components, thereby limiting device complexity while maintaining adjustment precision.
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 apparatus allows for precise and flexible adjustment of the static magnetic field distribution, improving imaging quality by enhancing uniformity and expanding the imaging space.
Implementation Method 1
magnetic members that hold magnetic members for adjusting a distribution of a static magnetic field
Data Source
AI summary
According to one embodiment, a static field adjustment apparatus includes a plurality of holding members that hold a magnetic member for adjusting a distribution of a static magnetic field to be used in magnetic resonance imaging. All or some of the holding members are stacked in an axial direction and/or a radial direction of a magnet that has an annular shape and generates the static magnetic field, in a first space on an internal diameter side of the magnet.