Temperature-Ramped 129Xe Spin-Exchange Optical Pumping

We describe temperature-ramped spin-exchange optical pumping (TR-SEOP) in an automated high-throughput batch-mode Xe-129 hyperpolarizer utilizing three key temperature regimes: (i) hot where the Xe-129 hypeipolarization rate is maximal, (ii) warm where the Xe-129 hyperpolarization approaches unity, and (iii) cool where hyperpolarized Xe-129 gas is transferred into a Tedlar bag with low Rb content (<5 ng per similar to 1. L dose) suitable for human imaging applications. Unlike with the conventional approach of batch-mode SEOP, here all three temperature regimes may be operated under continuous high-power (170 W) laser irradiation, and hypetpolarized Xe-129 gas is delivered without the need for a cryocollection step. The variable-temperature approach increased the SEOP rate by more than 2-fold compared to the constant-temperature polarization rate (e.g., giving effective values for the exponential buildup constant gamma(SEOP) of 62.5 +/- 3.7 x 10(-3) min(-1) vs 29.9 +/- 1.2 x 10-3 min-1) while achieving nearly the same maximum %P-xe value (88.0 +/- 0.8% vs 90.1% +/- 0.8%, for a 500 Torr (67 kPa) Xe cell loading corresponding to nuclear magnetic resonance/magnetic resonance imaging (NMR/MRI) enhancements of similar to 3.1 x 10(5) and similar to 2.32 x 10(8) at the relevant fields for clinical imaging and HP Xe-129 production of 3 T and 4 mT, respectively); moreover, the intercycle dead time was also significantly decreased. The higher-throughput TR-SEOP approach can be implemented without sacrificing the level of Xe-129 hyperpolarization or the experimental stability for automation making this approach beneficial for improving the overall Xe-129 production rate in clinical settings.