Motorized MR Shim Apparatus for Precise Field Homogeneity
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Solution Overview
Problem
Existing shim apparatuses for MR apparatuses are cumbersome, heavy, and difficult to position accurately, leading to inefficiencies in magnetic field homogeneity adjustments, and pose safety risks due to manual handling and potential eddy current induction.
Innovation Solution
A shim apparatus with a specimen holder, drive unit, and gear unit that allows for automated and precise positioning of MR reference specimens, utilizing an electric motor and magnetic field sensors for alignment, enabling accurate and safe adjustment of magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual rotation and locking mechanism is used, then the shim apparatus can be positioned, but the apparatus becomes heavy and unwieldy requiring solid rigid construction
Solution Approach 1:
The patent replaces the manual mechanical rotation and locking system with an automated drive unit that electrically or pneumatically rotates the specimen holder. This eliminates the need for heavy manual cranks, locking mechanisms, and rigid support structures, significantly reducing the apparatus weight while maintaining precise positioning capability through automated control.
Solution Approach 2:
The drive unit automatically positions the specimen holder without requiring manual intervention. The system self-regulates the rotation and positioning of MR reference specimens, eliminating the need for heavy-duty manual operating mechanisms and associated safety risks for service technicians.
2Productivity
If automated drive unit is implemented, then positioning speed and precision improve, but device complexity increases
Solution Approach 1:
The patent introduces a compact drive unit (electrical or pneumatic) that automatically rotates the specimen holder, replacing manual operation. This automated system significantly improves positioning speed and precision while maintaining relatively simple device architecture through the use of standard motorized components rather than complex mechanical linkages.
3Measurement precision
If aluminum ring is added for axis stability, then rotation position accuracy improves, but eddy currents are induced slowing down movement
Solution Approach 1:
The patent replaces the aluminum ring stabilization mechanism with a non-conductive support structure (such as plastic or composite materials) that maintains axis of rotation stability without inducing eddy currents. This allows the drive unit to move the specimen holder quickly and smoothly without electromagnetic resistance, preserving both positioning accuracy and movement speed.
4Reliability
If extension rods are provided for manual rotation at high field strengths, then safety is improved, but overall size increases preventing conventional car transportation
Solution Approach 1:
The patent replaces manual rotation operations with an automated drive unit, eliminating the need for extension rods and other manual handling aids. This reduces the apparatus to a compact size suitable for conventional transportation while maintaining service technician safety through automated operation that eliminates the need for technicians to place their heads in the patient tunnel during rotation operations.
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
Facilitates faster and more precise magnetic field homogeneity adjustments, reducing manual handling risks and apparatus size, while allowing operation in strong magnetic fields.
Implementation Method 1
a drive unit, the drive unit being configured to output a torque, the drive unit being electrical or pneumatic
Implementation Method 2
a gear unit, the gear unit being configured to transfer the torque output by the drive unit to the shaft
Implementation Method 3
utilizing an electric motor and magnetic field sensors for alignment
Implementation Method 4
the shaft is rotatable about an axis of rotation, the specimen holder being non-rotatably connected to the shaft
Data Source
AI summary
According to one or more example embodiments, a shim apparatus for an MR apparatus includes a specimen holder, the specimen holder including a plurality of MR reference specimens, the MR reference specimens being on the specimen holder; a frame; a shaft, the shaft being mounted on the frame such that the shaft is rotatable about an axis of rotation, the specimen holder being non-rotatably connected to the shaft, the MR reference specimens being spaced apart from the axis of rotation; a drive unit, the drive unit being configured to output a torque, the drive unit being electrical or pneumatic; and a gear unit, the gear unit being configured to transfer the torque output by the drive unit to the shaft and to rotate or swivel the MR reference specimens about the axis of rotation.