[en] The high cost of virgin ¹⁸O-enriched water has forced many researchers to study methods to purify and recycle enriched water after the first irradiation for the production of radiopharmaceuticals. In our study, [¹⁸O]H₂O was purified by ozonolysis and distillation. Analyses showed a large decrease in impurities after this treatment. The purification procedure was carried out after the production of 94 batches of [¹⁸F]-FDG, which were manufactured using a GE Minitrace cyclotron and a GE Mx TracerLab synthesizer. Saturation yields after bombardment, using virgin and re-purified water were, respectively, 2864±204 MBq/μA and 2727±167 MBq/μA, a decrease of 5.5%. The decrease in [¹⁸F]-FDG yield, from 67.2±0.7% to 65.5±0.9%, can be ascribed to the irradiation step only