Hyperpolarized (HP) ¹²⁹Xe NMR spectroscopy — a method that increases the NMR signal of xenon by up to five orders of magnitude — has become a valuable tool in many fields of modern research, including medical imaging. This technique has been greatly enhanced by the xenonizer setup, which was introduced a few years ago by researchers at the Max Planck Institute for Polymer Research, Mainz, Germany, and consists of a hollow-fiber membrane module driven by xenon gas and solvent.

The suitability of different hollow-fiber membranes for improved xenon dissolution in blood has been tested by N. Amor, K. Hamilton and co-workers, RWTH Aachen University and Research Center Jülich, Germany. The authors designed and assembled xenonizers using four different types of commercially available fibers: CELGARD, OXYPHAN, OXYPLUS, and silclear. They found that CELGARD is favorable if the fluid under investigation is exposed to the xenonizer for a longer period, and if a predefined oxygenation level and pH value are maintained.

OXYPLUS fibers are the least appropriate for HP ¹²⁹Xe dissolution while OXYPHAN fibers are best suited for applications requiring continuously dissolved HP ¹²⁹Xe as the highest signals are achieved with this material.

• NMR and MRI of Blood-Dissolved Hyperpolarized Xenon-129 in Different Hollow-Fiber Membranes
  N. Amor, K. Hamilton, M. Küppers, U. Steinseifer, S. Appelt, B. Blümich, T. Schmitz-Rode,
  ChemPhysChem 2011, 12.
  DOI: 10.1002/cphc.201100446