A non-radioactive, naturally occurring carbon 13 (13C) glucose isotopomer in which all six carbons are 13C, with potential imaging application. Upon administration of uniformly-labeled [U-13C] glucose, the glucose is taken up and metabolized by tumors and the 13C-containing metabolites can be imaged by 13C nuclear magnetic resonance (NMR) spectroscopy. Since tumor cells take up and metabolize glucose in higher amounts and through different pathways than normal cells, this agent may help assess the metabolic phenotype of the tumor. Check for active clinical trials using this agent.