A multisample 7 T dynamic nuclear polarization polarizer for preclinical hyperpolarized MR

Area of Science:

• Magnetic Resonance Imaging
• Nuclear Physics
• Cryogenics

Background:

• Dynamic nuclear polarization (DNP) significantly enhances nuclear spin signals in magnetic resonance (MR).
• Efficient hyperpolarization typically requires cryogenic temperatures (~1 K) and strong magnetic fields (3-10 T).
• Existing DNP polarizers often necessitate manual cryogen handling.

Purpose of the Study:

• To present a novel zero boil-off DNP polarizer system.
• To enable parallel polarization of multiple samples for hyperpolarized MR.
• To demonstrate the system's efficiency and performance with 13C-labeled pyruvate.

Main Methods:

• Development of a zero boil-off DNP polarizer operating at 1.35 K and 7 T.
• Utilized a static helium bath connected to a closed-cycle 4He refrigerator for sample cooling.
• Employed a modified commercial fluid path for sample delivery and polarization.
• Measured 13C polarization of [1-13C]pyruvate post-dissolution.

Main Results:

• The system successfully polarized two samples in parallel within a 12-minute interval.
• Achieved 36% liquid-state 13C polarization for [1-13C]pyruvate 26 seconds after dissolution.
• Extrapolated solid-state polarization reached 55%.
• Demonstrated potential for polarizing up to four samples concurrently.

Conclusions:

• The developed zero boil-off DNP polarizer offers an efficient and automated solution for hyperpolarized MR.
• The system is suitable for both in vitro and in vivo preclinical hyperpolarized MR applications.
• The design is adaptable for increased sample throughput, supporting advanced research needs.