XeUS: A second-generation automated open-source batch-mode clinical-scale hyperpolarizer.

We present a second-generation open-source automated batch-mode 129 Xe hyperpolarizer (XeUS GEN-2), designed for clinical-scale hyperpolarized (HP) 129 Xe production via spin-exchange optical pumping (SEOP) in the regimes of high Xe density (0.66-2.5 atm partial pressure) and resonant photon flux (~170 W, Δλ = 0.154 nm FWHM), without the need for cryo-collection typically employed by continuous-flow hyperpolarizers. An Arduino micro-controller was used for hyperpolarizer operation. Processing open-source software was employed to program a custom graphical user interface (GUI), capable of remote automation. The Arduino Integrated Development Environment (IDE) was used to design a variety of customized automation sequences such as temperature ramping, NMR signal acquisition, and SEOP cell refilling for increased reliability. A polycarbonate 3D-printed oven equipped with a thermo-electric cooler/heater provides thermal stability for SEOP for both binary (Xe/N 2 ) and ternary ( 4 He-containing) SEOP cell gas mixtures. Quantitative studies of the 129 Xe hyperpolarization process demonstrate that near-unity polarization can be achieved in a 0.5 L SEOP cell. For example, %P Xe of 93.2 ± 2.9% is achieved at 0.66 atm Xe pressure with polarization build-up rate constant γ SEOP  = 0.040 ± 0.005 min -1 , giving a max dose equivalent ≈ 0.11 L/h 100% hyperpolarized, 100% enriched 129 Xe; %P Xe of 72.6 ± 1.4% is achieved at 1.75 atm Xe pressure with γ SEOP of 0.041 ± 0.001 min -1 , yielding a corresponding max dose equivalent of 0.27 L/h. Quality assurance studies on this device have demonstrated the potential to refill SEOP cells hundreds of times without significant losses in performance, with average %P Xe  = 71.7%, (standard deviation σ P  = 1.52%) and mean polarization lifetime T 1  = 90.5 min, (standard deviation σ T  = 10.3 min) over the first ~200 gas mixture refills, with sufficient performance maintained across a further ~700 refills. These findings highlight numerous technological developments and have significant translational relevance for efficient production of gaseous HP 129 Xe contrast agents for use in clinical imaging and bio-sensing techniques.

Competing Interests: Declaration of Competing Interest Panayiotis Nikolaou, Boyd M. Goodson, and Eduard Y. Chekmenev declare a stake of ownership in XeUS Technologies, LTD.

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