Co-Polarization of (1-13C) Pyruvate and 13C Sodium Bicarbonate by Dynamic Nuclear Polarization Allows Simultaneous Assessment of in Vivo PH and Tumor Metabolism

David M. Wilson¹, Kayvan Keshari¹, Peder E. Larson¹, Albert P. Chen², Simon Hu¹, Robert A. Bok¹, Sarah J. Nelson¹, Daniel B. Vigneron¹, John Kurhanewicz¹

A new method for hyperpolarizing 13C- sodium bicarbonate was developed, and combined with a co-polarization approach that allowed dual polarization of both 13C sodium bicarbonate and [1-13C] pyruvate. Polarizations of 11% and 16% were achieved, respectively, with the corresponding T1’s 50 and 68s at 3T. Rapid equilibrium of injected 13C sodium bicarbonate with 13C CO2 allowed calculation of pH on a voxel by voxel basis, and tumor metabolism was observed by conversion of [1-13C] pyruvate to its metabolic products. These studies confirm the feasibilty of simultaneous measuring in-vivo pH and metabolism using nontoxic, endogenous species at clinically relevant field strengths.