Hyperpolarization is the
nuclear spinIn quantum mechanics and particle physics, spin is a fundamental characteristic property of elementary particles, composite particles , and atomic nuclei.It is worth noting that the intrinsic property of subatomic particles called spin and discussed in this article, is related in some small ways,...
polarization of a material far beyond
thermal equilibriumThermal equilibrium is a theoretical physical concept, used especially in theoretical texts, that means that all temperatures of interest are unchanging in time and uniform in space...
conditions. It is commonly applied to gases such as
129XeNaturally occurring xenon is made of nine stable isotopes. Xenon has the second highest number of stable isotopes. Only tin, with 10 stable isotopes, has more...
and
3HeHelium-3 is a light, non-radioactive isotope of helium with two protons and one neutron. It is rare on Earth, and is sought for use in nuclear fusion research...
which are then used, for instance, in hyperpolarized
magnetic resonance imaging (MRI)Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
of the lungs.
Other methods for hyperpolarization include
Dynamic Nuclear PolarisationDynamic nuclear polarization results from transferring spin polarization from electrons to nuclei, thereby aligning the nuclear spins to the extent that electron spins are aligned. Note that the alignment of electron spins at a given magnetic field and temperature is described by the Boltzmann...
(DNP) for solid materials at cryogenic temperatures and
para-hydrogenMolecular hydrogen occurs in two isomeric forms, one with its two proton spins aligned parallel , the other with its two proton spins aligned antiparallel...
used in chemical reactions in liquid solutions (PHIP).
DNP of nuclei like
13CCarbon-13 is a natural, stable isotope of carbon and one of the environmental isotopes. It makes up about 1.1% of all natural carbon on Earth.- Detection by mass spectrometry :...
or
15N at typically ≈1 K can be coupled with subsequent rapid dissolution yielding a room temperature solution containing hyperpolarized nuclei. This liquid can be used in
in vivo metabolic imaging for oncology and other applications. The
13C polarization level in the solid is reported as e.g. (64±5)% for a specific setup, and the losses during dissolution and transfer of the sample for actual
NMRNuclear magnetic resonance is a physical phenomenon in which magnetic nuclei in a magnetic field absorb and re-emit electromagnetic radiation...
or MRI measurements can be minimized to a few percent.
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