Preparation and bioevaluation of 111 In-DTPA-avastin for non-invasive tumor targeted imaging / 中华核医学与分子影像杂志

ABSTRACT

Objective To label human VEGF targeted bevacizumab (avastin) with 111In and to evaluate the application of 111 In?DTPA?avastin SPECT imaging for tumor diagnosis. Methods DTPA?avastin was prepared by coupling with a bifunctional chelating agent, and then labeled with 111 In to obtain 111 In?DTPA?avastin. The stability and molecular integrity of the labeled radiotracer were studied. Human hepatoma cell ( BEL7404) bearing nude mice tumor model was employed for tumor targeting evaluation. Gamma imaging was acquired after intravenous injection of 18.5 MBq probe. At the end of the observation, animals were sac?rificed for bio?distribution study. Results 111 In?DTPA?avastin tracer was synthesized and purified to a?chieve a radiochemical purity yield above 98% and specific activity up to 185 GBq/nmol. Its stability in 5%BSA was optimal, and the radiochemical purity after incubation for 96 h was over 90%. Gamma imaging re?sults showed that the tracer possessed definite tumor targeting property. Its biodistribution was consistent with that of normal in vivo antibody metabolism while possessing a good tumor?targeting property with a relatively high uptake of (3.8±0.8) %ID/g in tumor tissues 96 h after injection. Conclusions 111 In?DTPA?avastin tracer has good physicochemical properties, in vivo stability and good VEGF targeted binding. 111 In?DTPA?avastin has potential to be a new molecular probe for SPECT imaging.