Background: Folate receptor is highly expressed in tumor cells. Labeling folic acid offers a way of tumor targeting. Purpose: This study aims to explore the synthesis and in vivo imaging of 18F labeled folic derivative [18F]FPTZFA. Method: Starting from folic acid

through the amino and carboxyl ester forming reaction

we get FA-N3

and then FA-N3 is labeled with 18F-Pykyne in the presence of CuSO4

VcNa to get the compound of [18F]FPTZFA. [18F]FPTZFA then characterized by Radio-HPLC (High Performance Liquid Chromatography) and separated by Semi-HPLC. In vivo imaging was carried out in KB tumor-bearing nude mice after intravenous injection of [18F]FPTZFA via tail vein and biodistribution of [18F]FPTZFA was performed in these mice. Results: The overall reaction time lasts for 40 min

with radiochemical purity of 51%

and radiochemical yield of 37%. The autoradiography of mice tissues showed [18F]FPTZFA concentrated in liver

kidney and tumor. The %ID/g ratio in tumor tissue and muscle is 3.6

%ID/g ratio in tumor tissue and blood is 3.2. Conclusion: The high efficiency and high yield make the synthesis of [18F]FPTZFA more convenient and the %ID/g ratio indicates [18F]FPTZFA as a promising tumor targeting tracer. Abstract