Cyclotron biocontamination: Root cause analysis

1154 Objectives We previously reported biocontamination issues of our cyclotrons and associated fluoride delivery system. Following initial contamination with Ralstonia Picketii, persistent contamination with Methylobacterium Mesophilicum was observed. Early efforts to control biocontamination focused on sanitization with 70% sterile alcohol followed by sterile water and drying. Despite these measures, we observed increased bacterial growth, requiring greater sanitization frequency and PEEK tubing replacement. The aim of this work was to explore modifications to our sanitiziation programme and establish the root cause for our biocontamination issues. Methods Sanitization was performed using either a 70% sterile alcohol solution or acetonitrile followed by sterile water and drying. Samples were collected throughout the system and incubated and tested using R2A as growth medium. Sterilizing filters were introduced between the target filling system and the target and at the point of use in the hot and minicells. Results A sterilizing filter at point of use reduced bioburden below the limit of detection ( 3000cfu/mL) despite use of a sterilizing vent filter. No growth was detected ( Conclusions Sterile ethanol is a better sanitizing agent than acetonitrile. Introducing a sterilizing filter between the [18O]water vial and the target and delivery system provides the best protection against re-contamination. Persistent bioburden in the [18O]water vial suggests that the contamination occurs before the target and points to the self priming syringe used for target filling as the primary root for contamination. A sterilizing filter at point of use provides a suitable temporary solution to allow continuation of clinical production in case of biocontamination.