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.

The erythropoietin-producing hepatocellular receptor (Eph)B4 receptor is closely associa-ted with tumor growth and angiogenesis,which is over-expressed in a wide variety of tumors.Molecular probes targeted for EphB4 receptor can improve the accuracy and specificity of tumor diagnosis.A lot of molecular probes targeted for EphB4 receptor have been designed,which are expected to provide new means for the early diagnosis and therapeutics of tumors.

Objective To prepare 68Ga-PSMA-617 and perform its microPET imaging on both normal BALB/c mice and BGC-823 (PSMA expression) tumor bearing mice.Methods 68GaCl3 was eluted from 68Ge-68Ga generator by 0.05 mol/L HCl,then added to the DKFZ-PSMA-617 and heated at 85 ℃ for 5 min.The labeling efficiency and in vitro stability of 68Ga-PSMA-617 in sodium chloride solution and HAS were analyzed by radio-HPLC.Water partition coefficient and plasma protein binding rate were also evaluated.MicroPET imaging was performed in normal female BALB/c mice and human gastric tumor (BGC-823) bearing mice at 60 min post-injection of 68Ga-PSMA-617.18F-FDG was also injected to BGC-823 tumor bearing mice to acquire microPET imaging for contrast.Results The labeling yield of 68Ga-PSMA-617 was 97.9％,and it could be used directly without purification.68Ga-PSMA-617 showed good in vitro stability in sodium chloride solution and 5％ HAS,the radiochemical purities were 94.9％ and 81.0％ respectively at 80 min post-incubation.68Ga-PSMA-617 was water-solubility substance,and it cleared mainly through the kidneys.MicroPET imaging showed that 68Ga-PSMA-617 could be accumulated in tumor (T/NT=2.28),which was better than 18F-FDG.Conclusions Preparation of 68Ga-PSMA-617 is convenient and has a high labeling yield.It can specifically target to PSMA expression tumors and has a promising prospect in clinical application.