Objective: Radionuclide imaging is one of the major imaging modality for molecular imaging.Optical imaging, for its high molecular specificity and sensitivity, has indispensable position in biological study among all the molecular imaging technologies.More detail information will be obtained by combining both the nuclear and optical imaging modalities.When charged particles pass through an optically transparent medium at speeds greater than the speed of light in that medium will produce light signal (Cerenkov signal), radioisotope such as 131-I could produce the light imaged by Cerenkov Luminescence Imaging (CLI).Here, we report 131I labeled NGR peptide motif, an aminopeptidase N (CD13) ligand targets angiogenic blood vessels, and image its uptook by HT1080 tumor cell with luminescence imaging.Methods: 10ug of NGR containing peptide was labeled with 3.7MBq 131I by iodogen method.The CD 13 positive HT1080 cell cultured in 24-well plates were incubated with 131I-NGR 1 uCi,10uCi, 20uCi, 50uCi, 100uCi, 150uCi and 200uCi individually for 30minutes and washed by PBS for three times, the control cell was incubated with 50μCi Na 131I.Optical imaging was performed with the Xenogen In Vivo Imaging System for 3 minutes.The measured signals have subtracted the background image for quantification, it was quantified in unit of maximum photons per second per square centimetre and per steradian (P· s-1 ·cm-2 ·sr-1).Results: NGR peptide can be efficiently labeled by 131I with a labeling rate of 90%.HT1080 incubated with various amount of 131I-NGR can be imaged by CLI.There was a robust correlation between radioactivity versus average radiance.Ex vivo imaging analysis of 131I showed that optical signal proportionally increased with the increase of activities of 131 I-NGR.The more 13 1 I-NGR provided, the more clear signal will be, however there is not any signal when incubated with Na 131I.Similar strong signal can be seen when incubated with 150uCi and 200uCi of 131I-NGR HT1080 indicated a peak uptake.Conclusion: 131I-NGR specific target to HT1080 can be successfully imaged by CLI.The preliminary study may provide a new strategy for multimodality imaging by combining nuclear and optical imaging.