Pilot Quality-Assurance Study of a Third-Generation Batch-Mode Clinical-Scale Automated Xenon-129 Hyperpolarizer.

We present a pilot quality assurance (QA) study of a clinical-scale, automated, third-generation (GEN-3) 129 Xe hyperpolarizer employing batch-mode spin-exchange optical pumping (SEOP) with high-Xe densities (50% natural abundance Xe and 50% N 2 in ~2.6 atm total pressure sourced from Nova Gas Technologies) and rapid temperature ramping enabled by an aluminum heating jacket surrounding the 0.5 L SEOP cell. 129 Xe hyperpolarization was performed over the course of 700 gas loading cycles of the SEOP cell, simulating long-term hyperpolarized contrast agent production in a clinical lung imaging setting. High levels of 129 Xe polarization (avg. % P Xe = 51.0% with standard deviation σ P Xe = 3.0%) were recorded with fast 129 Xe polarization build-up time constants (avg. T b = 25.1 min with standard deviation σ T b = 3.1 min) across the first 500 SEOP cell refills, using moderate temperatures of 75 °C. These results demonstrate a more than 2-fold increase in build-up rate relative to previously demonstrated results in a comparable QA study on a second-generation (GEN-2) 129 Xe hyperpolarizer device, with only a minor reduction in maximum achievable % P Xe and with greater consistency over a larger number of SEOP cell refill processes at a similar polarization lifetime duration (avg. T 1 = 82.4 min, standard deviation σ T 1 = 10.8 min). Additionally, the effects of varying SEOP jacket temperatures, distribution of Rb metal, and preparation and operation of the fluid path are quantified in the context of device installation, performance optimization and maintenance to consistently produce high 129 Xe polarization values, build-up rates ( T b as low as 6 min) and lifetimes over the course of a typical high-throughput 129 Xe polarization SEOP cell life cycle. The results presented further demonstrate the significant potential for hyperpolarized 129 Xe contrast agent in imaging and bio-sensing applications on a clinical scale.