Synthesis of pyruvate-1-11C as a radiopharmaceutical for tumor imaging

Abstract

Pyruvate-1-¹¹C was prepared enzymatically by the exchange reaction of ¹¹CO₂ with the carboxyl group of pyruvic acid using pyruvate-ferredoxin oxidoreductase from Clostridium butyricum. ¹¹C-Labeled pyruvate was purified by sublimation in specially made glassware. The radiochemical yield of pure pyruvate-1-¹¹C was 80% 35 min after the end of bombardment. The distribution of ¹¹C in tumor-bearing rabbits after an i.v. injection of pyruvate-1-¹¹C was observed using a gamma camera. In contrast to normal organs, the tumor was positively visualized. We also conducted a number of successful clinical studies. A case of brain tumor which exhibited a positive image on positron-emission tomography (PET) using pyruvate-1-¹¹C is presented.