Modified Synthesis and Clinical Trial of ¹⁸F-Phe-BF₃

To improve the technology of fluorine-18 labelling of (1-ammonio-2-phenylethyl)trifluoroborate (Phe-BF₃). Phe-BF₃ was labelled by isotope exchange. Experimental groups used sodium chloride aqueous solution (pH=2) to elute fluorine-18 and the product solution was collected when the reaction system passed through an alumina cartridge; Control groups used K_2.2.2/K₂CO₃ solution to elute fluorine-18 and the product was concentrated by a C₁₈ cartridge first. Then, the product was eluted by 2 mL ethyl alcohol. After quality control, we used U87 glioma cells to study the specific binding experiment and then we performed PET imaging on healthy volunteers. The radiochemical yield of experimental groups was 10.6%, 9.78% and 10.4% and that of control grxoups were 3.86%, 4.28% and 4.33%. The radiochemical purity was more than 99% and the concentration of K_2.2.2 was more than 50 mg/L in control group. In the cell experiment, experimental group cell counting rate was (9.6±1.5)/min^-1, block group was (7.5±1.1)/min^-1 and control group was (4.4±0.9)/min^-1. What’s more, PET imaging results indicated the imaging agent mainly cleared by the kidneys and had no adverse effects in volunteers. The radiochemical yield and safety of experimental groups was obviously better. The results of cell uptake and PET imaging implied that ¹⁸F-Phe-BF₃ has the potential to be a good imaging agent for tumor diseases such as glioma.