Chapter 17: Continuous Flow and Dissolved Phase ¹²⁹Xe NMR/MRI for Quantification in Preclinical Study as well as Materials Science

Xenon shows characteristic affinities to a variety of media, and the chemical shift of ¹²⁹Xe varies widely over a range of more than 200 ppm when dissolved in different organic phases. Magnetic resonance spectroscopy and imaging (MRS/MRI) of hyperpolarized (HP) ¹²⁹Xe utilizing dissolved-phase signals are thus important tools for the investigation of functions of biological tissues/systems as well as molecular interactions in different media. However, there remain some difficulties, such as low sensitivity and short relaxation time T₂* in the dissolved-phase signals. In this chapter, we refer to technical aspects of overcoming these difficulties, i.e., continuous flow mode hyperpolarization with a stable and fresh supply of HP ¹²⁹Xe gas, and successful examples of its application. Some applications to materials science are also included.