Hyperpolarization (physics)

Hyperpolarization is the nuclear spin polarization of a material far beyond thermal equilibrium conditions.^[1] It is commonly applied to gases such as ¹²⁹Xe and ³He which are then used, for instance, in hyperpolarized magnetic resonance imaging (MRI) of the lungs.

Other methods for hyperpolarization include Dynamic Nuclear Polarisation (DNP) for solid materials at cryogenic temperatures and para-hydrogen used in chemical reactions in liquid solutions (PHIP).

DNP of nuclei like ¹³C or ¹⁵N at typically ≈1 K can be coupled with subsequent rapid dissolution yielding a room temperature solution containing hyperpolarized nuclei.^[2] This liquid can be used in in vivo metabolic imaging^[3] for oncology^[4] and other applications. The ¹³C polarization level in the solid is reported as e.g. (64±5)% for a specific setup,^[5] and the losses during dissolution and transfer of the sample for actual NMR or MRI measurements can be minimized to a few percent.

See also

• Dynamic nuclear polarisation
• Electron paramagnetic resonance

External links

• Europhysics - "Take a breath of polarized noble gas"
• University of Virginia - "Hyperpolarized Gas MR Imaging"
• Swiss DNP Initiative - "DNP-NMR ¹³C Hyperpolarization"

References

1. ^ Goldman, Maurice (1970). Spin Temperature and Nuclear Magnetic Resonance in Solids. Oxford University Press. 
2. ^ Jan H. Ardenkjær-Larsen, Björn Fridlund, Andreas Gram, Georg Hansson, Lennart Hansson, Mathilde H. Lerche, Rolf Servin, Mikkel Thaning, Klaes Golman (2003). "Increase in signal-to-noise ratio of > 10,000 times in liquid-state NMR". Proc. Natl. Acad. Sci. U.S.A. 100 (18): 10158–10163. Bibcode 2003PNAS..10010158A. doi:10.1073/pnas.1733835100. PMID 12930897. 
3. ^ Klaes Golman, Jan H. Ardenkjær-Larsen, J. Stefan Petersson, Sven Månsson, Ib Leunbach (2003). "Molecular imaging with endogenous substances". Proc. Natl. Acad. Sci. U.S.A. 100 (18): 10435–10439. Bibcode 2003PNAS..10010435G. doi:10.1073/pnas.1733836100. PMID 12930896. 
4. ^ Day SE, Kettunen MI, Gallagher FA, Hu DE, Lerche M, Wolber J, Golman K, Ardenkjaer-Larsen JH, Brindle KM (2007). "Detecting tumor response to treatment using hyperpolarized ¹³C magnetic resonance imaging and spectroscopy". Nat. Med. 13 (11): 1382–1387. doi:10.1038/nm1650. PMID 17965722. 

• ^ Haukur Jóhannesson, Sven Macholl, Jan H. Ardenkjær-Larsen (2009). "Dynamic Nuclear Polarization of [1-¹³C]pyruvic acid at 4.6 tesla". J. Magn. Reson. 197 (2): 167–175. PMID 19162518.