This study describes a single step conjugation of Glycylglycine (GlyGly) which is a small peptide, with [F-18]FDG via oxime formation. Amiooxy-functionalization of GlyGly (AO-GlyGly) was accomplished through the reaction of Boc-aminooxy succinimide ester. Conjugation reaction was performed at 100 A degrees C for 30 min in a vial containing AO-GlyGly and [F-18]FDG solution. The radiolabeled product ([F-18]FDG-GlyGly) was obtained with 98.65 +/- 0.35% yield without any purification step which makes this method more attractive for F-18 radiolabeling. The present study is concluded with an in vivo pilot animal PET study to assess biodistribution and kinetics of chemoselectively [F-18]FDG tagged GlyGly in vivo.