Gradient Field Deviation Detection Using Isotropic Diffusion Phantoms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for monitoring the non-linearity of gradient fields in magnetic resonance systems are complex and time-consuming, requiring specialized phantoms and expertise, which hinders the temporal stability assessment and precision of radiation therapy.
Innovation Solution
A method using isotropic diffusion phantoms with simple, unstructured fluid-filled hollow spheres to record image data sets with different diffusion-weightings, allowing for the creation of maps of apparent diffusion coefficients to test gradient field constancy and detect deviations over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MR phantoms with complex internal structures are used to monitor gradient field non-linearity, then measurement precision is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent extracts only the essential functional element (fluid-filled hollow spheres) from the complex phantom structure, removing unnecessary structural components while retaining the core measurement capability for gradient field non-linearity detection through diffusion-weighted imaging
Solution Approach 2:
The patent employs simple, easily manufacturable fluid-filled hollow spheres that can be quickly produced and replaced, eliminating the need for complex, expensive, and time-consuming phantom constructions while maintaining adequate measurement precision for gradient field monitoring
2Measurement precision
If conventional MR phantoms with complex internal structures are used, then measurement precision is improved, but evaluation time and expertise requirements increase
Solution Approach 1:
The patent extracts the essential measurement function from complex phantom evaluation procedures, using simple fluid-filled spheres that can be quickly scanned and evaluated, thereby reducing the time and expertise required for gradient field stability assessment while maintaining measurement precision
Solution Approach 2:
The patent uses simple geometric copies (fluid-filled hollow spheres) that replicate the necessary diffusion characteristics for measurement without requiring complex internal structures, enabling rapid evaluation while preserving measurement accuracy for gradient field monitoring
3Device complexity
If gradient field non-linearity is not monitored, then device complexity is reduced, but reliability of precision irradiation positioning decreases
Solution Approach 1:
The patent implements a self-service monitoring approach where the magnetic resonance system itself performs gradient field stability assessment using simple fluid-filled phantoms, eliminating the need for external complex monitoring equipment while ensuring reliable precision irradiation positioning through regular ADC map comparisons
Solution Approach 2:
The patent establishes a feedback mechanism where ADC maps obtained from fluid-filled phantom scans are compared with reference values to detect gradient field non-linearity changes, enabling continuous monitoring and maintenance of positioning accuracy for precision irradiation without requiring complex additional systems
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 simplifies the monitoring of gradient field stability, enabling easier detection of deviations and adaptive distortion correction, thereby improving the precision of magnetic resonance imaging and radiation therapy.
Implementation Method 1
The gradient fields generate a position-dependency of the Larmor frequency of the spins, whereby a position encoding of the reception signal may be achieved
Implementation Method 2
providing at least one first and one second image data set of a phantom with isotropic diffusion properties, recorded with a diffusion-weighted imaging sequence
Data Source
AI summary
The disclosure relates to a method for ascertaining a deviation of at least one gradient field of a magnetic resonance system from a reference. The method includes providing at least one first image data set and one second image data set of a phantom with isotropic diffusion properties, recorded with a diffusion-weighted imaging sequence, wherein the first image data set and the second image data set are recorded with different diffusion-weightings along a gradient direction to be tested of the gradient field using the magnetic resonance system. The method further includes ascertaining a map of apparent diffusion coefficients from the image data sets for at least a portion of the image points of the image data sets. The method further includes comparing the apparent diffusion coefficients with the reference.