Effect of saccharide additives on response of ferrous-agarose-xylenol orange radiotherapy gel dosimeters

B. J. Healy, M. H. Zahmatkesh, K. N. Nitschke, C. Baldock

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Glucose, sucrose, starch, and locust bean gum have been used as additives to the ferrous-agarose-xylenol orange (FAX) gel dosimeter. The saccharide enhanced dosimeters were found to have a higher dose sensitivity over a standard FAX gel as measured by both optical density change and magnetic resonance imaging (MRI). With optical density measurement, OD-dose sensitivity increases were up to 55% for glucose, 122% for sucrose and 43% for starch, while locust bean gum did not give a consistent response. With MRI, R 1-dose sensitivity increases were up to 178% with sucrose addition. The FAX gel with sucrose was studied in greatest detail. The OD-dose sensitivity dependence on cooling rate was reduced for the sucrose FAX gel over the standard FAX gel, which has significant implications for uniform dose sensitivity in large gel phantoms. The thermal oxidation rate in the sucrose FAX gel was up to 2.3 times higher than in the standard gel. The OD-dose sensitivity of oxygenated sucrose FAX gels was 4.3 times greater than standard FAX gels, while continued enhancement in OD-dose sensitivity with increased sucrose concentrations beyond 2.0 g/l was found only for the oxygenated sucrose FAX gels. Both the molar absorption coefficient of the ferric ion-xylenol orange complex at 543 nm and gel pH were not affected by the presence of sucrose, with the implication that the higher OD-dose sensitivity of gels with saccharides is due to increased chain reaction production of ferric ions.
Original languageEnglish
Pages (from-to)2282-2291
Number of pages10
JournalMedical Physics
Volume30
Issue number9
DOIs
Publication statusPublished - 2003
Externally publishedYes

Keywords

  • Agarose gel
  • Mri
  • Optical density
  • Radiation dosimetry

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