Biomolecules provide an enormous reservoir for developing specific probes for immunoPET to visualize biological processes and detect biomarkers of interests in vivo.Diabodies(dimers of single-chain Fv antibody fragments)retain the high binding specificity and affinity of their parental antibodies,which can reach maximum uptake in target tissue in 1-2 h post injection,and clear with a terminal half-life of 3-4 h,making them optimal for immunoPET.However,efficient 18F-labeling of diabodies remains challenging.Here we demonstrated the use of a digital microfluidic droplet generator(DMDG)chip to rapidly scout conditions for radiolabeling diabodies using N-succinimidyl-4-[18F]fluorobenzoate([18F]SFB).