# Molecular hydrogen and catalytic combustion in the production of hyperpolarized 83Kr and 129Xe MRI contrast agents.
> 超偏極83Krおよび129Xe MRIコントラスト剤製造における分子水素と触媒燃焼の応用


## Abstract

This study introduces a novel approach to producing hyperpolarized (hp) 83Kr and 129Xe for MRI applications by substituting molecular hydrogen for nitrogen as the buffer gas in spin-exchange optical pumping (SEOP). Nuclear spin polarizations of P=29% for 83Kr and P=63% for 129Xe were achieved and reproduced across multiple SEOP cycles, despite laser-induced rubidium hydride (RbH) formation. After SEOP, the hydrogen was eliminated through catalytic combustion without detectable loss of hyperpolarized spin states in either noble gas. This approach enables, for the first time, purification of highly spin-polarized 83Kr for in vivo MRI of pulmonary surfaces. Additionally, catalytic combustion offers a simpler alternative to cryogenic separation for hp 129Xe purification, potentially enabling continuous on-demand production.

### Mechanism

Molecular hydrogen replaces nitrogen as the buffer gas during spin-exchange optical pumping (SEOP) of 83Kr and 129Xe. After polarization, H2 is removed via catalytic combustion, preserving the hyperpolarized spin states of both noble gases and enabling their purification without cryogenic separation.

## Bibliographic

- **Authors**: Rogers NJ, Hill-Casey F, Stupic KF, Six JS, Lesbats C, Rigby SP, et al.
- **Journal**: Proc Natl Acad Sci U S A
- **Year**: 2016 (2016-03-22)
- **PMID**: [26961001](https://pubmed.ncbi.nlm.nih.gov/26961001/)
- **DOI**: [10.1073/pnas.1600379113](https://doi.org/10.1073/pnas.1600379113)
- **PMC**: [PMC4812722](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4812722/)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: not assessed

## Delivery context

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 26961001. https://h2-papers.org/en/papers/26961001
> **Source**: PubMed PMID [26961001](https://pubmed.ncbi.nlm.nih.gov/26961001/)