18F fluoroethylations: different strategies for the rapid translation of 11C-methylated radiotracers.
BACKGROUND
The translation of 11C-labeled compounds into their respective 18F-labeled derivatives is an important tool in the rapid development of positron emission tomography (PET) tracers. Thus, our aim was the development of a general method for the preparation of 18F-fluoroethylated compounds that (a) is applicable to a variety of precursors, (b) can be performed in a fully automated commercially available synthesizer and (c) enables this rapid translation of 11C-methylated tracers into their 18F-fluoroethylated analogs sharing the same precursor molecules.


METHODS
Ten methods for the preparation and purification of different 18F-fluoroethylating agents were compared. Subsequently, five 18F-labeled PET tracers were synthesized under fully automated conditions.


RESULTS
Radiochemical yields ranged from 34.4% to 60.8%, and time consumption ranged from 20 to 55 min for all methods. Use of 1-bromo-2-[18F]fluoroethane and distillation evinced as the method of choice.


CONCLUSIONS
We were able to develop a general method for the preparation of a variety of 18F-fluoroethylated molecules. The provided tool is solely based on commercially available resources and has the potential to simplify and accelerate innovative PET tracer development in the future.
Wadsak
Wolfgang
W
Department of Nuclear Medicine, Medical University of Vienna, Vienna A-1090, Austria.
Mien
Leonhard-Key
LK
Ettlinger
Dagmar E
DE
Eidherr
Harald
H
Haeusler
Daniela
D
Sindelar
Karoline-Maria
KM
Keppler
Bernhard K
BK
Dudczak
Robert
R
Kletter
Kurt
K
Mitterhauser
Markus
M
D002250:Carbon Radioisotopes / Q000737:chemistry*; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D007553:Isotope Labeling / Q000295:instrumentation / Q000379:methods*; D008745:Methylation; D019275:Radiopharmaceuticals / Q000138:chemical synthesis*
D002250:Carbon Radioisotopes; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals