16α-[18F]fluoro-17β-estrogen (18F-FES) is a specific molecular imaging probe of estrogen receptor of breast cancer and has been applied into the clinic diagnosis of breast cancer by PET/CT imaging for the optimization of treatment plan

monitoring of treatment efficiency

improvement of treatment outcome and reduction of treatment cost.A fast

reliable automated synthesis procedure of 18 F-FES was developed by modifying a commercial Explora FDG 4 module based on a "two-step

two-pot" radiochemical process and a simple separation way via solid phase extraction (SPE) in this study.In the first step

radiofluorination of precursor 3-O-(methoxymethyl)-16

17-O-sulfuryl-16-epiestriol and activated 18 F ion was carried out at 100°C for 10 min to form 18 F-labeled intermediate

which was separated via SPE based on silica column

so as to remove the non-reacted starting materials.In the second step

acidic hydrolysis of 18 F-labeled intermediate was heated at 90°C for 10 min to produce the target product 18 F-FES

which was purified by a serial column consisted of two C18 and one Al 2 O 3 cartridges.This newly developed production procedure of 18 F-FES could be completed within 70 min with radiochemical yield of about 30% and radiochemical purity of over 95%.