ENHANCEMENT OF SOLUTION NMR AND MRI WITH LASER-POLARIZED XENON

Optical pumping with laser light can be used to polarize the nuclear s pins of gaseous xenon-129. When hyperpolarized xenon-129 is dissolved in liquids, a time-dependent departure of the proton spin polarization from its thermal equilibrium is observed, The variation of the magnet ization is an unexpected manifestation of the nuclear Overhauser effec t, a consequence of cross-relaxation between the spins of solution pro tons and dissolved xenon-129. Time-resolved magnetic resonance images of both nuclei in solution show that the proton magnetization is selec tively perturbed in regions containing spin-polarized xenon-129. This effect could find use in nuclear magnetic resonance spectroscopy of su rfaces and proteins and in magnetic resonance imaging.