title: Microbial challenge tests on nonradioactive TiO2-based 68Ge/68Ga generator columns.
abstract: OBJECTIVE
  The aim of this study was to test the survival of microorganisms in eluents used for (68)Ge/(68)Ga generators and for regeneration of nonradioactive (68)Ge/(68)Ga generator columns after high microbial load. Nonradioactive generator columns were loaded with various microorganisms and tested to determine whether the microorganisms were proliferating or surviving in eluates of the columns.
  
  
  METHODS
  TiO(2) columns used in a commercially available (68)Ge/(68)Ga generators for absorption of (68)Ge were loaded with greater than 10(7) colony-forming units (CFU) of Staphylococcus aureus, Clostridium sporogenes, Candida albicans, Helicobacter pylori, Aspergillus niger and Deinococcus radiodurans. Columns were eluted with 0.1 N HCl under standard eluting conditions. Elutions, over a prolonged time period, were tested for endotoxins, sterility and number of CFU.
  
  
  RESULTS
  Initial tests on the eluent (0.1 N HCl) already showed limited survival of microorganisms. Using TiO(2) generator columns, even with a higher load of microorganisms no survival of any microorganism could be detected in subsequent elutions, neither in colony-forming unit assays nor in sterility testing. In addition, endotoxin tests showed no elevated levels in any of the eluent samples, even days after incubation.
  
  
  CONCLUSIONS
  The conditions used in this type of (68)Ge/(68)Ga generator are highly unfavourable for survival or growth of microorganisms. The risks associated with incidental microbial contaminations during the lifetime of such a generator are therefore very low.
authors.affiliation: Clinical Department of Nuclear Medicine, Innsbruck Medical University, Innsbruck, Austria. milospetrik@seznam.cz
authors.forename: Milos
authors.initials: M
authors.lastname: Petrik
authors.forename: Andrea
authors.initials: A
authors.lastname: Schuessele
authors.forename: Susanne
authors.initials: S
authors.lastname: Perkhofer
authors.forename: Cornelia
authors.initials: C
authors.lastname: Lass-Flörl
authors.forename: Dirk
authors.initials: D
authors.lastname: Becker
authors.forename: Clemens
authors.initials: C
authors.lastname: Decristoforo
mesh_terms: D004866:Equipment Contamination; D005658:Fungi / Q000302:isolation & purification*; D005710:Gallium Radioisotopes; D005857:Germanium; D006090:Gram-Negative Bacteria / Q000302:isolation & purification*; D006094:Gram-Positive Bacteria / Q000302:isolation & purification*; D006801:Humans; D011868:Radioisotopes; D011876:Radionuclide Generators
chemical_list: D005710:Gallium Radioisotopes; D011868:Radioisotopes; D005857:Germanium