A1 Refereed original research article in a scientific journal
Influence of transport line material on the molar activity of cyclotron produced [18F]fluoride
Authors: Nina Savisto, Jörgen Bergman, Jussi Aromaa, Sarita Forsback, Olli Eskola, Tapio Viljanen, Johan Rajander, Stefan Johansson, Julian Grigg, Sajinder Luthra, Olof Solin
Publisher: Elsevier Inc.
Publication year: 2018
Journal: Nuclear Medicine and Biology
Journal name in source: Nuclear Medicine and Biology
Volume: 64-65
First page : 8
Last page: 15
Number of pages: 8
ISSN: 0969-8051
eISSN: 1872-9614
DOI: https://doi.org/10.1016/j.nucmedbio.2018.06.004
Introduction
Production of fluorine-18-labeled radiopharmaceuticals is always associated with the varying levels of the same compound containing stable fluorine-19. In practice, this affects the molar activity (Am), defined as amount of radioactivity divided by the molar quantity (Bq/mol).
We have focused on studying how the material of the transport tubing connecting the cyclotron target chamber to the synthesis device affects the concentration of fluoride in the water arriving to the reaction vessel and subsequently the Am of the fluorine-18 labeled radiopharmaceuticals produced.
Methods
Batches of irradiated and non-irradiated water were analyzed for fluoride content after being transported via non-fluorinated (PEEK, PP) and fluorinated (PTFE, ETFE) tubing or using no tubing at all. Am for the [18F]fluoride was determined and compared with the Am of [18F]fluciclatide, synthesized from the same [18F]fluoride containing batches of water.
Results
Significantly higher concentrations of fluoride were seen in irradiated water that was transported in fluorinated tubing compared to non-irradiated water transported in tubing of the same material. This elevation of fluoride concentration is presumably caused by the interaction of ionizing radiation with the fluorinated tubing used between the target chamber and hot cell. Likewise, a significant difference was seen for PEEK tubing (non-fluorinated). This could be due to the fact that fluorine containing compounds are used in the manufacture of PEEK.
When using fluorinated tubing for transport of the irradiated water, the resulting fluciclatide concentrations were significantly higher compared to when using non-fluorinated tubing. No significant difference was seen between fluciclatide concentrations when PTFE or ETFE tubing was compared to each other. Using no tubing resulted in lowest fluciclatide concentration.
Conclusions
Fluorinated tubing is a source of stable fluoride, and Am can be increased by using non-fluorinated transport tubing. Of all the tubing materials studied PP is preferred.
