Radical-Free Hyperpolarized α-Ketoglutarate: Non-persistent radicals for Dissolution DNP

Motivation: Hyperpolarized (HP) 13C-α-Ketoglutarate (αKG) can be used for assessing the metabolic profile of low-grade glioma, a deadly condition requiring improved diagnostic methods. Goal(s): To demonstrate the utility of HP photo-irradiated 13C-αKG as a metabolic imaging 13C-probe. Approach: High concentration 13C-αKG, irradiated with UV light followed by solid-state DNP at 6.7T and 1.4K, and liquid-state HP measurements. Results: UV-induced radical build-up of 1 mM/s. Solid-state polarization of 45+10% (equivalent to optimized pyruvate/trityl sample), 4-fold signal increase from microwave frequency modulation, dissolution DNP and liquid-state polarization of 16+5% (at the point of measurement). Impact: HP photo-irradiated 13C-αKG can provide valuable metabolic information for assessing low-grade glioma1, potentially leading to improved diagnostic and treatment evaluation methods.