Nuclear Science and Techniques

Abstract:

Asialoglycoprotein receptor (ASGP-R) is a hepatic membrane receptor that uniquely exists on the surface of mammalian hepatocytes, and has been used as target of liver functional imaging agents for many years. We labeled the Galactosyl-neoglycoalbumin (NGA) with 18F to get a PET molecular probe 18F-FB-NGA and evaluated its ability as a liver functional PET imaging agent. The 18F-FB-NGA was prepared with NGA by conjugation with Nsuccinimidyl- 4-18F-fluorobenzoate (18F-SFB) and purified with PD-10 desalting column. The radiolabeling yield and radiochemical purity of 18F-FB-NGA were determined by radio-HPLC. Starting with 18F-F–, the total time for 18F-FB -NGA was about 120±10 min. The decay-corrected radiochemical yield is about 25–30%. The radiochemical purity of purified 18F-FB-NGA was more than 98%. Labeled with 185–1850 MBq 18F-SFB, the specific activity of 18F -FBNGA was estimated to be 7.83–78.3 TBq/mmol. Biodistribution of 18F-FB-NGA in normal mice was investigated after injection through the tail vein. The results showed that the liver accumulated 39.47±3.42 and 12.12±6.11%ID/g at 10 and 30 min after injection, respectively. Dynamic MicroPET images in mice were acquired with and without block after injection of the radiotracer, respectively. High liver activity accumulation was observed at 5 min after injection in normal group. On the contrary, the liver accumulation was significantly lower after block, indicating the specific binding to ASGP-R. 18F-FB-NGA is probably a potential PET liver imaging agent.

Key words: Asialoglycoprotein receptor, 18F-FB-NGA, Biodistribution, PET Imaging