Harald E. Mller1,2,
1Max Planck Institute for Human
Cognitive and Brain Sciences, Leipzig, Germany; 2Center for In
Vivo Microscopy, Duke University Medical Center, Durham, NC, United States
In
experiments involving repeated deliveries of hyperpolarized (HP) gas, the
delivered magnetization is not constant due to unavoidable relaxation during
HP gas storage. Moreover, the spin-lattice relaxation time, T1R, inside flexible plastic bags, which often serve as HP
gas reservoirs, is not constant. The change of T1R of HP 129Xe
in a deflating bag can be quantitatively described by a model based on simple
spherical geometry and the kinetic theory of gases to account for relaxation
mechanisms in the bulk gas and on the container walls. Results might be used
for optimizing signal utilization and improving the point-spread function.