Vacuum chamber. ++++++++++++++++. Substrate. Niobium Sputtered Havar Foils for FDG Production. Sputtered atoms. +. V. _. Ar plasma. Ar +. Ar. e -. Target. - - - - - - - - - - - - - - - -. Introduction. Havar Foils - Post Production. Havar Limitations. Acknowledgements.
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Niobium Sputtered Havar Foils for FDG Production
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Havar Foils - Post Production
R Johnson1, J Wilson, C Backhouse2, B Der, C Doerkson and S McQuarrie
Edmonton PET Centre, 2 University of Alberta, Edmonton, AB, 1 Advanced Cyclotron Systems, Richmond, BC Canada
Niobium Sputtered Foils - Cont.
The Edmonton PET Centre currently supplies FDG to hospitals as far away as 1300 km. In order to meet this commitment in a tight multi run schedule, the production of 18F had to be maximized, while preserving the chemical environment within the water target so that the 18F could be subsequently used to provide FDG at high and reproducible yields. Although our niobium target was able to produce > 275 GBq (in a one hour irradiation) and operate with beam currents in excess of 100uA, subsequent FDG production yields were compromised. An ensuing study determined that the source of the problem was due to excessive metal ions coming from the Havar entrance foil and released into the water during irradiations that exceed 70uA.
Our improvement on the design of a high-yield cyclotron target is involves facile sputtering of selected material onto traditional high strength metal foils used in cyclotron targets. We have recently successfully tested this concept.
Ion Analysis on Irradiated H218O (48 hrs)
Side 2 niobium sputtered foil
Only 93Mo observed with niobium foil.
(Scale is 1/10 of spectrum on left)
activated trace metals in the target water arise from the constituent metals of Havar.
X-Y axis (cm)
Time duration: 2hours
Beam specifications: 16.5MeV, 100mA
Model Specifics: No water cooling or evaporation of water
Niobium Sputtered Foils – Post Production
2042 uA hr
Side 1 (broad beam spot)
13200 uA hr
Side 1 niobium sputtered foil after 5585 uA hr
Side 2 (tight beam spot)
569 uA hr
1223 uA hr