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Technical Note: Preliminary investigations into the use of a functionalised polymer to reduce diffusion in Fricke gel dosimeters
Author(s) -
Smith S. T.,
Masters K.S.,
Hosokawa K.,
Blinco J. P.,
Crowe S. B.,
Kairn T.,
Trapp J. V.
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4934827
Subject(s) - xylenol orange , polyvinyl alcohol , dosimeter , polymer , materials science , nuclear chemistry , polyvinyl acetate , methyl orange , dosimetry , chemistry , composite material , organic chemistry , nuclear medicine , catalysis , medicine , photocatalysis
Purpose: 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.