Hyperpolarized Noble Gases

High equilibrium spin polarizations in solid due to optical pumping and their applications were discussed.  

2 Chemical Shift. The relationship between pore size and chemical shifts for many controlled pore glasses has been established by the exploration of hyperpolarized xenon gas in the porous solids. A number of recent developments in Xe NMR speetroscopy and microimaging were reported with direct applications to the study of mesopore space in solids (37 references). Experiments illustrated include the rapid eharaeterization of the void space in porous solids, including the in situ proeesses such as diffusion and dehydration, and imaging with chemical shift resolution. Chemieal shift imaging with continuously flowing hyper-polarized xenon was applied to the characterization of materials.  

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Hyperpolarized Noble Gases, Gas Phase Imaging and Other Nuclei... 

Moller H, Chen X, Chawla M et al. Sensitivity and resolution in 3D NMR microscopy of the lung with hyperpolarized noble gases. Magn Reson Med 1999 41 800-808. 

MR imaging by hyperpolarized noble gas, He-3 (helium) or Xe-129 (xenon), has become a promising approach for visualizing lung anatomy and function. It has been theoretically predicted that low field strengths and low frequencies (0.05-0.2T 1.62-6.5 MHz for He-3 and 0.59-2.35 MHz for Xe-129) may provide optimal signal-to-noise ratio and spatial resolution for clinical HNG(Hyperporalized Nobel Gas) MR imaging. 

Hyperpolarized noble gas atoms, like xenon, can interact with protons and other nuclei via dipolar cross-relaxation, a mechanism which is supported by stochastic processes of motion. By means of this interaction, hyperpolarized xenon can transfer its polarization to protons and other nuclei of interest. An efficient way to make use of this SPINOE mechanism is to freeze hyperpolarized xenon onto the surface of the sample. During the defrosting process large amounts of xenon can penetrate into the liquid sample, resulting in a large SPINOE enhancement. 

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