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Hyperpolarized Xenon for NMR and MRI Applications
Published on: September 6, 2012
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Continuous Delivery of Hyperpolarized Xenon-129 Gas Using a "Stopped-Flow" Clinical-Scale Cryogen-Free Hyperpolarizer
Md Raduanul H Chowdhury1, Clementinah Oladun1, Firoz Ahmed1
1Department of Chemistry, Integrative Biosciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan 48202, United States.
Analytical Chemistry
|February 4, 2025
Summary
This study demonstrates a novel method for continuous delivery of hyperpolarized 129Xe gas, overcoming limitations of current techniques for preclinical imaging and materials science applications. This cryogen-free approach enables on-demand gas supply, enhancing usability and accessibility.
Area of Science:
- Nuclear Magnetic Resonance (NMR) Spectroscopy and Imaging
- Medical Imaging Physics
- Hyperpolarized Contrast Agents
Background:
- FDA-approved hyperpolarized (HP) 129Xe gas is crucial for functional lung imaging, typically administered as a bolus.
- Continuous HP 129Xe delivery is desired for preclinical pulmonary imaging and materials science applications requiring sustained gas flow.
- Current continuous-flow HP 129Xe production necessitates cryo-collection, hindering on-demand delivery and continuous operation.
Purpose of the Study:
- To develop and validate a method for continuous, cryogen-free delivery of HP 129Xe gas.
- To enable on-demand gas supply for applications requiring sustained HP 129Xe flow.
- To assess the feasibility of using a stopped-flow hyperpolarizer for continuous gas delivery.
Main Methods:
- Utilized a clinical-scale stopped-flow 129Xe hyperpolarizer to produce a batch of HP 129Xe (50:50 Xe:N2) with a long polarization lifetime (>2 h).
- Delivered the HP 129Xe gas through PEEK tubing (2.5 m) at flow rates of 3-180 sccm into a 5 mm NMR tube.
- Quantified gas polarization using in situ low-field NMR polarimetry and verified with 0.35 T clinical MRI.
Main Results:
- Demonstrated continuous-flow delivery of HP 129Xe for up to 15 minutes at flow rates of 45-150 sccm with minimal polarization loss.
- Achieved 16-19% polarization in the delivered gas, starting from 19% polarization within the hyperpolarizer.
- 129Xe relaxation measurements confirmed minimal polarization decay within the PEEK tubing and NMR tube.
Conclusions:
- The developed stopped-flow method enables on-demand, cryogen-free delivery of HP 129Xe gas.
- This technique supports continuous gas flow for extended periods, suitable for preclinical imaging and materials science.
- The approach broadens the accessibility and application range of hyperpolarized 129Xe for various scientific and medical fields.
