Cryogen-Free Cryostat for MRI Hyperpolarized Sample Preparation
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Solution Overview
Problem
Current MRI and NMR spectroscopy techniques face challenges in achieving high sensitivity due to low nuclear spin polarization, and existing hyperpolarization methods require cryogen usage, which poses practical and environmental challenges, especially in clinical settings.
Innovation Solution
A cryogen-free cryostat structure and method for producing hyperpolarized samples using a vacuum environment and a cooling device to maintain selected temperatures, allowing for polarization and melting of solid samples with minimal polarization loss, without the need for cryogens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If flow cryostat with cryogen is used to cool the magnet bore, then low temperature space is achieved for hyperpolarization, but cryogen storage and handling challenges arise
Solution Approach 1:
The invention extracts the cryogen from the magnet bore environment by using a separate cryogen-free cryostat positioned outside the bore. The cryostat produces cold temperatures through mechanical refrigeration and transfers this cooling capability to the bore region without introducing actual cryogenic fluids into the magnet environment, thereby eliminating storage and handling challenges while maintaining the required low temperature space for hyperpolarization
Solution Approach 2:
The invention introduces a thermal intermediary system consisting of a cryostat with mechanical refrigeration that acts as a mediator between the room temperature environment and the magnet bore. The cryostat generates cold temperatures and transfers them through its structure to cool the bore region indirectly, avoiding direct contact with cryogens in the magnet bore while still achieving the necessary low temperature conditions for hyperpolarization
2Measurement precision
If solid polarized sample is dissolved manually, then polarization enhancement is achieved, but polarization loss occurs during transfer
Solution Approach 1:
The invention performs preliminary action by pre-positioning the dissolving solvent and dissolving mechanism within the magnet bore before the solid polarized sample is introduced. The sample is dissolved in situ within the polarizing magnet field, eliminating the need to transfer the sample outside the magnet. This preliminary arrangement of dissolving components ensures that the sample remains in the polarizing field throughout the dissolution process, maximizing polarization enhancement while minimizing polarization loss during transfer
3Measurement precision
If dedicated hyperpolarization system with integrated cryostat is used, then high polarization is achieved, but device complexity increases
Solution Approach 1:
The invention segments the hyperpolarization system into separate functional modules: a cryogen-free cryostat positioned outside the magnet bore that generates cold temperatures through mechanical refrigeration, and a separate sample introduction and dissolution system within the bore. This segmentation allows the complex cryogenic function to be isolated in an external unit, reducing the complexity within the magnet system itself while maintaining the capability to achieve high polarization levels through the coordinated operation of these modular components
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 enhances nuclear spin polarization with reduced cryogen usage, simplifying handling and maintenance, and maintaining high sensitivity for MRI applications while minimizing polarization loss during sample transformation from solid to solution.
Implementation Method 1
a cryostat structure for use in polarizing a solid sample, wherein the cryostat structure comprises a bore capable of being evacuated in order to create a vacuum environment
Implementation Method 2
a cooling device inserted in the bore for maintaining a selected temperature in the sample
Implementation Method 3
the polarized sample was manually lifted out of the cryostat and within about 1 second dissolved in deuterium oxide at 40° C.
Data Source
AI summary
A method and an apparatus for producing hyperpolarized samples for use in magnetic resonance imaging (MRI) are provided. The apparatus comprises an ultra-compact cryogen-free cryostat structure for use in polarizing a sample of selected material, wherein the cryostat structure comprises a central bore being adapted to be evacuated to create a vacuum region, and a cooling device inserted in the central bore or optionally close to the central bore for maintaining a selected temperature of the sample.