Temperature-Ramped (129)Xe Spin-Exchange Optical Pumping

[Image: see text] We describe temperature-ramped spin-exchange optical pumping (TR-SEOP) in an automated high-throughput batch-mode (129)Xe hyperpolarizer utilizing three key temperature regimes: (i) “hot”—where the (129)Xe hyperpolarization rate is maximal, (ii) “warm”—where the (129)Xe hyperpolarization approaches unity, and (iii) “cool”—where hyperpolarized (129)Xe gas is transferred into a Tedlar bag with low Rb content (<5 ng per ∼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 hyperpolarized (129)Xe 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 γ(SEOP) of 62.5 ± 3.7 × 10(–3) min(–1) vs 29.9 ± 1.2 × 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 ∼3.1 × 10(5) and ∼2.32 × 10(8) at the relevant fields for clinical imaging and HP (129)Xe 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 (129)Xe hyperpolarization or the experimental stability for automation—making this approach beneficial for improving the overall (129)Xe production rate in clinical settings.