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Background and Importance ( 68Ga)Ga-PSMA (Prostate-Specific Membrane Antigen labelled with Gallium-68) is a radiopharmaceutical (RP) prepared extemporaneously in a multidose vial for multiple dispensations. It is intravenously administered for prostate cancer diagnosis using polypropylene, polyisoprene, or silicone syringes. No data are currently available regarding the stability of this solution in contact with these materials.Aim and Objectives This study aimed to assess the stability of ( 68Ga)Ga-PSMA in the injection syringe to determine the maximum allowable time for possible reassignment in case of unforeseen delays, provided that radioactivity remains sufficient.Material and Methods Radiochemical purity (RCP) was used as the stability marker. RCP values from the multidose vial and from dispensed syringes were compared. Four quality controls (QC) were performed at 30-minute intervals: T0, T30, T60, and T90. The analytical method was thin-layer chromatography (TLC). A 1 µL aliquot was applied on glass microfiber chromatography paper impregnated with silica gel. The mobile phase consisted of methanol and ammonium acetate (50/50, v/v). RCP values obtained at T0 were compared with those at subsequent times using the non-parametric Wilcoxon paired test (α = 0.05).Results Ten ( 68Ga)Ga-PSMA syntheses were analysed. No significant differences in mean RCP were observed between T0 and T30 (p = 0.10) or T60 (p = 0.13). Only RCP at T90 (p = 0.0091) was significantly different from T0. Across all syntheses, RCP coefficients of variation remained below the 2% variability threshold (1.62, 0.14, 0.29, 0.29, 0.27, 0.23, 0.17, 0.66, 0.24, 0.16), confirming temporal stability.Conclusion and Relevance No degradation of ( 68Ga)Ga-PSMA radiochemical purity was observed up to 60 minutes after dispensation, suggesting sufficient stability for temporary storage in syringes and possible dose reassignment. The significant variation observed at 90 minutes may result from the limited number of syntheses analysed. Further studies on larger datasets are needed to confirm and refine these findings.References and/or Acknowledgements NA No conflict of interest