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Title
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A study of four radiochromic films currently used for (2D) radiation dosimetry
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Author
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Abstract
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| We have measured the dose, D, and dose rate, D', dependences of the radiation-induced change in optical absorption of four radiochromic films currently used for (2D) dosimetry: GafChromic (R) types EBT3, MD-V3, HD-V2 and HD-810. We have irradiated the films using two Co-60 gamma-ray sources with dose rates of similar to 2 and similar to 30 Gy/min and a 200 kVp X-ray source with dose rates from similar to 0.2 to similar to 1.0 Gy/min. The 48-bit RGB image files of the films, obtained using an Epson V700 flatbed scanner, were color-channel separated and the red, green and blue"pixel levels, P(D), were determined using ImageJ software. The relationship P(D)/P(0)=[1+hD/m]/ [1+D/m] is found to provide a good description of the dose dependence for all four films at all dose rates. The parameter his the "plateau level" of P(D)/P(0) approached at high doses, i.e. P(infinity)/P(0). The parameter m is the "median-dose" for which P(D)/P(0)(1+h)/2 which is the half point in the dynamic range of the particular film. The best-fit values of m over the dose rate range from similar to 0.2 to similar to 25 Gy/min using the red pixels were 1.42 +/- 0.03, 11.1 +/- 0.4, 63.6 +/- 0.9 and 60.6 +/- 1.6 Gy for EBT3, MD-V3, HD-V2 and HD-810 respectively. Using the green pixels the median dose is 1.8 times larger for the first 3 films and 2.5 times larger for HD-810. The blue pixels are considered unsuitable for dosimetry because of the large value of h (>0.4) and the resulting small dynamic range. |
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Language
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English
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Source (journal)
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Radiation physics and chemistry. - Oxford
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Publication
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Oxford
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2017
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ISSN
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0969-806X
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DOI
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10.1016/J.RADPHYSCHEM.2016.12.006
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Volume/pages
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133
(2017)
, p. 37-44
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ISI
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000393259000006
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Full text (Publisher's DOI)
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