dissolved in an acetonitrile water 2 3 mixture and lyophilized the product was purified by hplc to give octreotate 1 1 2 trimethyl 1h benz e indole propanoic acid conjugate 10 monooctreotate bispentylcarboxymethylindocyanine dye cytate 3 60 and bisoctreotate bispentylcarboxymethylindocyanine dye cytate 4 30 the dye peptide conjugates are sparingly soluble in water and require the addition of solubilizing agents or co solvents addition of 1 20 aqueous ethanol to the conjugates partially quenched the fluorescence intensity in vitro and the fluorescence was completely quenched in vivo the conjugate was not detected by the charged coupled device ccd camera addition of 1 50 of dmso either re established or increased the fluorescence intensity of the conjugates in vitro and in vivo the dye fluorescence remained intense for over one week the dmso formulations were well tolerated by experimental animals used for this invention imaging of pancreatic ductal adenocarcinoma dsl 6a with indocyanine green icg a non invasive in vivo fluorescence imaging apparatus was employed to assess the efficacy of contrast agents developed for tumor detection in animal models a lasermax inc laser diode of nominal wavelength 780 nm and nominal power of 40 mw was used the detector was a princeton instruments model rte ccd 1317 k 2 ccd camera with a rodenstock 10 mm f2 lens stock 542 032 002 20 attached an 830 nm interference lens cvi laser corp part f10 830 4 2 was mounted in front of the ccd input lens such that only emitted fluorescent light from the contrast agent was imaged typically an image of the animal.