title: Technical Note: Preliminary investigations into the use of a functionalised polymer to reduce diffusion in Fricke gel dosimeters.
abstract: OBJECTIVE
  A modification of the existing PVA-FX hydrogel has been made to investigate the use of a functionalised polymer in a Fricke gel dosimetry system to decrease Fe(3+) diffusion.
  
  
  METHODS
  The chelating agent, xylenol orange, was chemically bonded to the gelling agent, polyvinyl alcohol (PVA) to create xylenol orange functionalised PVA (XO-PVA). A gel was created from the XO-PVA (20% w/v) with ferrous sulfate (0.4 mM) and sulfuric acid (50 mM).
  
  
  RESULTS
  This resulted in an optical density dose sensitivity of 0.014 Gy(-1), an auto-oxidation rate of 0.0005 h(-1), and a diffusion rate of 0.129 mm(2) h(-1); an 8% reduction compared to the original PVA-FX gel, which in practical terms adds approximately 1 h to the time span between irradiation and accurate read-out.
  
  
  CONCLUSIONS
  Because this initial method of chemically bonding xylenol orange to polyvinyl alcohol has inherently low conversion, the improvement on existing gel systems is minimal when compared to the drawbacks. More efficient methods of functionalising polyvinyl alcohol with xylenol orange must be developed for this system to gain clinical relevance.
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia.
authors.forename: S T
authors.initials: ST
authors.lastname: Smith
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia.
authors.forename: K-S
authors.initials: KS
authors.lastname: Masters
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Hosokawa
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia.
authors.forename: J P
authors.initials: JP
authors.lastname: Blinco
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia and Cancer Care Services, Royal Brisbane and Women's Hospital, Brisbane 4006, Australia.
authors.forename: S B
authors.initials: SB
authors.lastname: Crowe
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia and Genesis Cancer Care Queensland, Brisbane 4066, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Kairn
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia.
authors.forename: J V
authors.initials: JV
authors.lastname: Trapp
mesh_terms: D002412:Cations / Q000737:chemistry; D004058:Diffusion; D004305:Dose-Response Relationship, Drug; D005296:Ferrous Compounds / Q000737:chemistry; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects; D007501:Iron / Q000737:chemistry; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry; D011142:Polyvinyl Alcohol / Q000737:chemistry; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods; D013454:Sulfoxides / Q000737:chemistry; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D002412:Cations; D005296:Ferrous Compounds; D020100:Hydrogels; D010636:Phenols; D013454:Sulfoxides; D013464:Sulfuric Acids; C020748:ferrous sulfate; D011142:Polyvinyl Alcohol; D007501:Iron; C033158:sulfuric acid; C016833:xylenol orange