One aim of the present study was to apply existing technology developed for direct cyclotron-based production of 68Ga using a liquid target (i.e. by irradiation of an isotopically enriched salt solution of 68Zn) and chemical processing to isolate [68Ga]GaCl3to the production of 66Ga and [66Ga]GaCl3. The second aim of this study was to radiolabel and investigate the imaging properties of 66Ga for PET-imaging of GRPR expression over time using the bombesin-like peptide NOTA-PEG2-RM26 in a preclinical prostate cancer model. This evidence concerns the gene GRPR and prostate carcinoma.