Enhancement of surface and biological magnetic resonance using laser-polarized noble gases

Laser-polarized noble gas nuclei such as 3He or 129Xe are spin systems far from thermal equilibrium. Their enhanced nuclear spin polarization results in a corresponding sensitivity gain in nuclear magnetic resonance (NMR) experiments. Recent developments in the application of laser-polarized noble gases are summarized in the present article, especially with respect to surface and biological magnetic resonance. Optical pumping and spin exchange, basic processes for the production of laser-polarized noble gases, are described. The enhancement of surface NMR using laser-polarized 129Xe under continuous flow and magic angle spinning conditions is demonstrated. Spin polarization transfer from laser-polarized 129Xe nuclei to other nuclei is described. Laser-polarized noble gases are of increasing importance in biological magnetic resonance; their use in clinical magnetic resonance imaging is of special interest. Applications of laser-polarized 129Xe in solution NMR spectroscopy are also discussed, especially with respect to systems of biological relevance. ©1999 John Wiley & Sons, Inc. Concepts Magn Reson 11: 313–335, 1999