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

Laser-polarized noble gas nuclei such as He-3 or Xe-129 are spin systems fa r from thermal equilibrium. Their enhanced nuclear spin polarization result s in a corresponding sensitivity gain in nuclear magnetic resonance (NMR) e xperiments. Recent developments in the application of laser-polarized noble gases are summarized in the present article, especially with respect to su rface and biological magnetic resonance. Optical pumping and spin exchange, basic processes for the production of laser-polarized noble gases, are des cribed. The enhancement of surface NMR using laser-polarized Xe-129 under c ontinuous flow and magic angle spinning conditions is demonstrated. Spin po larization transfer from laser-polarized Xe-129 nuclei to other nuclei is d escribed. Laser-polarized noble gases are of increasing importance in biolo gical magnetic resonance; their use in clinical magnetic resonance imaging is of special interest. Applications of laser-polarized Xe-129 in solution NMR spectroscopy are also discussed, especially with respect to systems of biological relevance. (C) 1999 John Wiley & Sons, Inc.