278. Performance and Reproducibility of 13C and 15N Hyperpolarization Using A Cryogen-Free DNP Polarizer

Arianna Ferrari, Josh Peters, Mariia Anikeeva, Andrey Pravdivtsev, Frowin Ellermann, Kolja Them, Olga Will, Eva Peschke, Hikari Yoshihara, Olav Jansen and Jan-Bernd Hövener; Scientific Reports; (2022); DOI: 10.21203/rs.3.rs-1315188/v1 (open access)

The setup, operational procedures and performance of a cryogen-free device for producing hyperpolarized contrast agents using dissolution dynamic nuclear polarization (dDNP) in a preclinical imaging center is described. The polarization was optimized using the solid-state, DNP-enhanced NMR signal to calibrate the sample position, microwave and NMR frequency and power and flip angle. The polarization of a standard formulation to yield ~ 4 mL, 60 mM 1-13C-pyruvic acid in an aqueous solution was quantified in five experiments to 13C-P = (38 ± 6) % (19 ± 1) s after dissolution. The mono-exponential time constant of the build-up of the solid-state polarization was quantified to (1032 ± 22) s. We achieved a duty cycle of 1.5 h that includes sample loading, monitoring the polarization build-up, dissolution and preparation for the next run. After injection of the contrast agent in vivo, pyruvate, pyruvate hydrate, lactate, and alanine were observed, by measuring metabolite maps. Based on this work sequence, hyperpolarized 15N urea was obtained (15N-P = (5.6 ± 0.8) % (30 ± 3) s after dissolution).