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

We present a second-generation open-source automated batch-mode Xe-129 hyperpolarizer (XeUS GEN-2), designed for clinical-scale hyperpolarized (HP) Xe-129 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 (similar to 170 W, Delta lambda = 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 thermoelectric cooler/heater provides thermal stability for SEOP for both binary (Xe/N-2) and ternary (He-4-containing) SEOP cell gas mixtures. Quantitative studies of the Xe-129 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 gamma(SEOP) = 0.040 +/- 0.005 min(-1), giving a max dose equivalent approximate to 0.11 L/h 100% hyperpolarized, 100% enriched Xe-129; %P-Xe of 72.6 +/- 1.4% is achieved at 1.75 atm Xe pressure with gamma(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 sigma(P) = 1.52%) and mean polarization lifetime T-1 = 90.5 min, (standard deviation sigma(T) = 10.3 min) over the first similar to 200 gas mixture refills, with sufficient performance maintained across a further similar to 700 refills. These findings highlight numerous technological developments and have significant translational relevance for efficient production of gaseous HP Xe-129 contrast agents for use in clinical imaging and bio-sensing techniques. (C) 2020 Elsevier Inc. All rights reserved.