Figure 2.

¹²⁹Xe NMR spectra in fresh human blood. Spectrum A was obtained using normal xenon by accumulating 520 scans over 1.5 h (the xenon pressure is about 1 atmosphere). Spectrum B was acquired with one scan after injection of 1 cc of laser-polarized xenon/saline solution into 1 cc of RBC sample. The signal enhancement was estimated to be three orders of magnitude. The ¹²⁹Xe NMR signal at a chemical shift of 216 ppm is characteristic of xenon in the RBC, and the signal at 192 ppm is of xenon in the saline/plasma mixture. NMR experiments were performed on a Bruker AM-400 spectrometer.