Abstract: To investigate the causes of ¹⁸F-FDG-(OAc)₄ residual in ¹⁸F-FDG and the discrepancy of bio-distributions between ¹⁸F-FDG-(OAc)₄ and ¹⁸F-FDG, ¹⁸F-FDG was prepared by hydrolysis on C-18.The effect of NaOH dosage, elution rate, and eluent pH on ¹⁸F-FDG-(OAc)₄ residual, the metabolism and biodistribution profiles of ¹⁸F-FDG-(OAc)₄ in mice were stutied. The results showed that insufficiency of NaOH was the main reason for ¹⁸F-FDG-(OAc)₄ residual, while the elution rate and the pH of the eluent posed no impact. After injecting ¹⁸F-FDG-(OAc)₄ 60 minutes, the partially hydrolyzed product and ¹⁸F-FDG-(OAc)₄ were found in metabolite of blood、urine and brain of the mice. The mice bio-distribution suggested that the uptake of ¹⁸F-FDG-(OAc)₄ and ¹⁸F-FDG by organs followed the same pattern apart from muscle.