THE EFFECT OF TARGET-GAS PURITY ON THE CHEMICAL FORM OF F-18 DURING F-18-F2 PRODUCTION USING THE NEON-FLUORINE TARGET

  • 1 January 1980
    • journal article
    • research article
    • Vol. 21  (8) , 758-762
Abstract
Irradiation of gas mixtures of F2/Ne (20Ne .**GRAPHIC**. 18F) containing levels (< 0.1%) of N2, CO2 or CF4 resulted in the production of unacceptable levels of 18F-labeled NF3 and CF4 at the expense of 18F-F2. Analytical gas chromatographic methods were devised to determine contaminant levels in the target gas and in the products arising from them. Commercial mixtures of 1% F2/Ne, pure F2 and Ne were analyzed for contaminants (N2, O2, CO, CO2 and CF4) and found to vary widely in the levels of these impurities from batch to batch. The N2 levels in the 1% F2/Ne mixtures varied at 0.039-0.49%; the CO2 levels varied at 0.028-0.13%. No detectable impurities were found in the Ne (research purity), but F2 contained .apprx. 11% CF4. Reproducibly high yields of 18F-F2 were obtained is the levels of N2, CO2 and CF4 in the final target gas mixture were < 0.01% and carrier F2 was .apprx. 0.1%. Hydrocarbons and CO were not detected in these gas mixtures, but could decrease yields of 18F-F2.