Radiation Chemistry of the Ferrous Sulfate-Benzoic Acid-Xylenol Orange System

Gupta, B.L.; Bhat, R.; Gomathy, K.R.; Susheela, B.

doi:10.2307/3574902

Cited by 44 publications

(25 citation statements)

References 15 publications

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“…The greater R 1 -dose sensitivity of the FA gel without xylenol orange is consistent with increased ferric ion yield without xylenol orange as observed for the ferrousbenzoic acid ͑FB͒ dosimeter over the FBX dosimeter. 8 Also, the lower R 1 values in the FAX gel over the FA gel is consistent with reduced relaxivity in the presence of the chelator which effectively moves hydration water away from the paramagnetic ion. R 1 -dose sensitivities of 12.5, 34.8, and 82.8 s Ϫ1 kGy Ϫ1 for FAX, FAX/sucrose, and FA gels, respectively, were calculated from the initial linear response up to 10 Gy in Fig.…”

Section: Resultsmentioning

confidence: 68%

“…It was however observed that the ferric ion yield of the FBX dosimeter was less than that in the ferrousbenzoic acid solution due to the reaction of OH • radicals with the xylenol orange dye. 8 Preparation of ferrous-doped agarose gels involves dissolving the agarose gel powder at temperatures above 90°C, with the ferrous or ferrous-xylenol orange solution added after the agarose gel has cooled but before it has set. It has been found previously that the sensitivity of the ferrousdoped agarose gel is dependent on the gel cooling rate.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2003

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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, R1-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.

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Section: Resultsmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

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

et al. 2003

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“…The radiochromic chemical solution used in this investigation was xylenol orange complexed with the ferrous ion ͑FBX͒. The radiochemistry of the FBX liquid dosimeter has been studied extensively 18,[20][21][22][23][24] and has been shown to have properties very similar to the standard liquid Fricke solution. When the ferrous ion ͑Fe 2ϩ ) is irradiated, it oxidizes to form the ferric ion ͑Fe 3ϩ ) and the corresponding complex with xylenol causes a change in absorption, which has a broad peak centered at a wavelength of 540 nm ͑Fig.…”

Section: A Fbx-gelatin Preparationmentioning

confidence: 99%

Optical CT reconstruction of 3D dose distributions using the ferrous–benzoic–xylenol (FBX) gel dosimeter

1998

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In recent years, magnetic-resonance imaging of gelatin doped with the Fricke solution has been applied to the direct measurement of three-dimensional (3D) radiation dose distributions. However, the 3D dose distribution can also be imaged more economically and efficiently using the method of optical absorption computed tomography. This is accomplished by first preparing a gelatin matrix containing a radiochromic dye and mapping the radiation-induced local change in the optical absorption coefficient. Ferrous-Benzoic-Xylenol (FBX) was the dye of choice for this investigation. The complex formed by Fe3+ and xylenol orange exhibits a linear change in optical attenuation (cm-1) with radiation dose in the range between 0 and 1000 cGy, and the local concentration of this complex can be probed using a green laser light (lambda = 543.5 nm). An optical computed tomography (CT) scanner was constructed analogous to a first-generation x-ray CT scanner, using a He-Ne laser, photodiodes, and rotation-translation stages controlled by a personal computer. The optical CT scanner itself can reconstruct attenuation coefficients to a baseline accuracy of < 2% while yielding dose images accurate to within 5% when other uncertainties are taken into account. Optical tomography is complicated by the reflection and refraction of light rays in the phantom materials, producing a blind spot in the transmission profiles which, results in a significant dose artifact in the reconstructed images. In this report we develop corrections used to reduce this artifact and yield accurate dosimetric maps. We also report the chemical reaction kinetics, the dose sensitivity and spatial resolution (< 1 mm3) obtained by optical absorption computed tomography. The article concludes with sample dose distributions produced by "cross-field" 6 MV x-ray beams, including a radiosurgery example.

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“…It is difficult to compare the G(Fe 3+ ) values as these authors have used sodium chloride and triply distilled water whilst xylenol orange and singly distilled water have been used in our work. However it has been shown that XO reduces the G value in FBX (ferrous-benzoic acid-xylenol orange) 18 . Healy et al 15 also reported a reduction in dose sensitivity which they suggested could be caused by a reduction in G value in the FAX gel compared to a ferrousagarose gel.…”

Section: Comparison Of G(fe 3+ ) For Different Gel Systemsmentioning

confidence: 99%

Characterisation of a Ferrous Agarose Xylenol ( FAX ) gel for radiotherapy dose measurement

Leong

Kandaiya

Seng³

2007

Australas. Phys. Eng. Sci. Med.

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The oxidation of ferrous to ferric ions due to ionizing radiation has been used for chemical dosimetry since 1927. The introduction of metal indicator dye xylenol orange (XO) sensitises the measurement of ferric ion yield. A ferrous sulphate- agarose- xylenol orange (FAX) gel was prepared and the gel then exposed to dose ranging from 0.2 to 10 Gy using various high energy photon and electron beams from a linear accelerator. Some general characteristics of FAX such as energy dependence, optical density (OD)-dose relationship, reproducibility and auto-oxidation of ferrous ions were analysed. The radiation yield G of the gel was calculated for gels prepared in oxygen and in air and the values were 46.3 +/- 2.1 and 40.9 +/- 1.4 Fe3+ per 100 eV for photons respectively. However for stock gel which was kept for 5 days pre-irradiation the G value decreased to 36.6 +/- 1.1. The gel shows linearity in OD-dose relationship, energy independence and reproducibility over the dose range investigated. Auto-oxidation of ferrous ions resulted in optical density changes of less than 1.5% per day.

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Radiation Chemistry of the Ferrous Sulfate-Benzoic Acid-Xylenol Orange System

Cited by 44 publications

References 15 publications

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

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

Optical CT reconstruction of 3D dose distributions using the ferrous–benzoic–xylenol (FBX) gel dosimeter

Characterisation of a Ferrous Agarose Xylenol ( FAX ) gel for radiotherapy dose measurement

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