MRI Magnetic Field Control for Limited-Bandwidth Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic resonance tomography units require complex shielding cabins to reduce emissions and immissions, which is costly and inefficient.
Innovation Solution
A magnetic resonance tomography unit with a magnet unit and magnetic controller that adjusts the homogeneous magnetic field B0 to keep emissions within limited frequency bands, allowing reduced shielding measures and active interference suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If complex shielding cabins are installed around the magnetic resonance tomography unit, then emissions and immissions are reduced to comply with legal limits, but device complexity and cost increase
Solution Approach 1:
The patent changes the frequency parameter of the magnetic resonance tomography unit by dynamically adjusting the main magnetic field strength. This shifts the Larmor frequency and corresponding radio frequency emissions to different bands, allowing operation in frequency ranges with less stringent shielding requirements while still complying with legal emission limits
Solution Approach 2:
The system implements dynamic adjustment of the magnetic field strength during operation, allowing the frequency of emissions to be changed in real-time. This dynamic capability enables the system to adapt to different shielding configurations and operational requirements, reducing the need for fixed complex shielding structures
2Object-generated harmful factors
If the homogeneous magnetic field B0 is changed in a short time, then emissions are kept within limited frequency bands, but magnetic field stability deteriorates
Solution Approach 1:
The patent employs periodic adjustment of the magnetic field strength in synchronization with the pulse sequence timing. The field is changed during specific intervals (e.g., during relaxation periods) and maintained stable during data acquisition, creating a periodic pattern that keeps emissions controlled while preserving image quality
Solution Approach 2:
The system performs preliminary adjustment of the magnetic field before data acquisition to pre-establish the desired frequency band. By anticipating the need for stable field conditions during imaging, the system prepares the magnetic field in advance, minimizing disruptions during the actual measurement process
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
Reduces the need for complex shielding by maintaining emissions within permissible frequency ranges, enabling less complex shielding or eliminating it altogether while ensuring compliance with legal limits.
Implementation Method 1
a magnet unit with a magnetic controller for generating a homogenous magnetic field B0. The homogenous magnetic field B0 provides alignment of the nuclear spins and specifies a Larmor frequency for nuclear spins
Implementation Method 2
The magnetic controller is configured to change the B0 magnetic field in a short, predetermined time within image acquisition of an object under examination
Implementation Method 3
using an alternating magnetic field, excite these nuclear spins for precession around this alignment
Implementation Method 4
The precession or return of the spins from this excited state into a state with lower energy in turn generates a magnetic alternating field in response, which is received via antennae
Data Source
AI summary
A system includes two magnetic resonance tomography units. Each of the magnetic resonance tomography units includes a magnet unit having a magnetic controller for generating a homogenous magnetic field. The magnetic controller is configured to change the homogenous magnetic field in a short, predetermined time within image acquisition of an object under examination, such that a Larmor frequency for a predetermined layer of the object under examination remains in a predetermined frequency range. A first magnetic resonance tomography unit has a first predetermined frequency range, and a second magnetic resonance tomography unit has a second predetermined frequency range. The first predetermined frequency range and the second predetermined frequence range are disjoint.