Rajat K. Ghosh1, Stephen J. Kadlecek1, Nicholas N. Kuzma1, Jan Henrik Ardenkjaer-Larsen2, 3, Giuseppe Pileio4, Malcolm H. Levitt4, Rahim R. Rizi1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States; 2Electrical Engineering, , The Technical University of Denmark, Lyngby, Denmark; 3GE Healthcare , Broendby, Denmark; 4University of Southampton
The utility of hyperpolarized tracers is limited by polarization lifetime. Transferring spin order to a singlet state can significantly increase polarization lifetimes in nitrous oxide dissolved in a liquid solvent. The longitudinal relaxation of nitrous oxide is largely dominated by the spin-rotation interaction. In this work we formulate a model to describe the relaxation of nitrous oxide dissolved in various solvents, and avenues to lengthen the singlet lifetime by altering the characteristics of the dissolving solvent. We experimentally investigate the effect of altering the temperature of the solvent, as well as the effect of varying viscosity and hydrodynamic radius.