Objective To evaluate the feasibility of dopamine D2 receptor imaging agent (s)-(-)-N-(1-allylpyrrolidine-2-N-methyl)-5-(3-18F)-2, 3-dimethoxy Benzamide (18F-Fallypride) for targeting islet cell imaging. Methods (1) Cytology experiment: Islet cells of 15×103 cells/well were incubated with 3.70 kBq/well 18F-Fallypride for 1 h and the uptake rate of cells was calculated (cell counts/(supernatant counts+cell counts)×100%). Under the same experiment conditions, 6 inhibiting groups were administrated with different concentration of dopamine inhibitors droperidol (1.0×10-6, 4.0×10-6, 2.0×10-5, 1.0×10-4, 5.0×10-4 and 1.0×10-3 mol/L, respectively). After 30 min, 3.70 kBq of 18F-Fallypride was added to each inhibiting group, and the inhibiting rate was calculated. (2) Autoradiography: 18 normal ICR mice were divided into 6 groups. For group A, ICR mice were injected with 18F-Fallypride (55±5) MBq/mice through tail vein. For the other 5 inhibiting groups (group B-F), ICR mice were injected with different doses of droperidol (0.2, 0.4, 0.6, 0.8 and 1.0 mg/kg, respectively), and after 30 min 18F-Fallypride were injected through tail vein. Ten minutes later, pancreas of ICR mice was taken for preparation of tissue section autoradiography. The data were analyzed by one-way analysis of variance and the least significant difference t test. Results (1) The 18F-Fallypride uptake rate of control group was (18.40±1.21)%. The uptake rates of inhibiting groups were (16.11±1.37)%, (15.76±0.99)%, (13.90±1.02)%, (8.86±0.73)%, (7.26±0.62)% and (6.92±0.58)%, respectively, which decreased with the decreasing concentration of droperidol(F=50.01, P<0.01). When the concentration of droperidol was 1.0×10-4 mol/L, the uptake rate reached the lowest with inhibiting rate of 51.85%. (2) The autoradiography showed that the pancreas gray scale value of group A was 1.21×106 digital light units (DLU)/mm2. The pancreas gray scale value of groups B to F decreased with increasing concentration of inhibitor: 0.93×106, 0.77×106, 0.59×106, 0.32×106 and 0.25×106 DLU/mm2, respectively. Conclusions 18F-Fallypride may specifically and efficiently bind to dopamine receptors of islet cells. It may be a potential tracer for islet cells imaging. Key words: Islets of langerhans; Fallypride; Fluorine radioisotopes