Ferromagnetic Body Temperature Control for MRI Magnetic Field Homogeneity
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Solution Overview
Problem
Superconductive magnetic devices face challenges in maintaining magnetic field homogeneity due to fluctuations in applied current values during demagnetization and re-excitation, which are difficult and costly to correct using existing methods, especially in superconductive magnets with ferromagnetic bodies.
Innovation Solution
A magnetic resonance imaging apparatus with a superconductive magnet and a temperature control system that calculates and adjusts the temperature of ferromagnetic bodies to compensate for magnetic field inhomogeneities caused by current errors, using a temperature variation calculating device and a temperature control device to maintain homogeneous magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If magnetic field homogeneity is adjusted by incrementally disposing or removing magnetic homogeneity adjusting bodies, then magnetic field homogeneity is improved, but the adjustment process takes a long time
Solution Approach 1:
The patent changes the temperature parameter of the ferromagnetic body to adjust magnetic field homogeneity. By heating or cooling the ferromagnetic body, its magnetization changes, which in turn adjusts the magnetic field distribution. This eliminates the need for time-consuming mechanical adjustment of magnetic homogeneity adjusting bodies while maintaining improved magnetic field homogeneity.
2Reliability
If coils for adjusting magnetic field are mounted and energized to compensate fluctuation, then magnetic field homogeneity is maintained, but device complexity increases
Solution Approach 1:
Instead of using additional adjustment coils to compensate for magnetic field fluctuations, the patent changes the temperature parameter of the existing ferromagnetic body. This approach maintains magnetic field homogeneity while avoiding the complexity of additional coils and their control systems.
3Manufacturing precision
If temperature control devices are added to suppress temperature fluctuation of magnetic material, then magnetic field homogeneity is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces dynamic temperature control of the ferromagnetic body to compensate for magnetic field fluctuations. By making the temperature adjustable rather than fixed, the system can actively compensate for variations in applied current values, maintaining magnetic field homogeneity without requiring complex additional adjustment mechanisms.
4Reliability
If magnetic field adjustment is performed frequently to correct fluctuation, then magnetic field homogeneity is maintained, but operation time increases
Solution Approach 1:
The patent uses temperature as a controllable parameter to adjust magnetic field homogeneity. This method allows for rapid adjustment compared to mechanical repositioning of magnetic homogeneity adjusting bodies, thereby maintaining reliable magnetic field homogeneity while minimizing impact on operation time and productivity.
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
This approach effectively and inexpensively adjusts magnetic field homogeneity by controlling the temperature of ferromagnetic bodies, providing a cost-effective solution for maintaining homogeneous magnetic fields in superconductive magnetic devices and MRI apparatuses.
Implementation Method 1
it is possible to sufficiently compensate fluctuation of magnetic field homogeneity attributed to error in applied current value of superconductive coil by changing temperature of ferromagnetic body itself
Implementation Method 2
a magnetic field generating device having a superconductive coil and a ferromagnetic body
Data Source
AI summary
The magnetic field homogeneity adjusting device (20) is characterized by comprising a magnetic field distribution measuring unit (21) for measuring the magnetic field distribution in the magnetic field space, a temperature variation calculating unit (22) for calculating the temperature variation of the ferromagnetic bodies needed to improve the homogeneity of the magnetic field space based on the measured magnetic field distribution, and a temperature control unit (12) for setting a temperature control value of the ferromagnetic bodies according to the calculated temperature variation.