Technical Note: Homogeneity of Gafchromic® EBT2 film
Technical Note: Homogeneity of Gafchromic® EBT2 film
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DOI：
10.1118/1.3368601
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发表时间：
2010-04-01
期刊：
影响因子：
3.8
通讯作者：
Jaekel, Oliver
中科院分区：
文献类型：
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作者：
Hartmann, Bernadette;Martisikova, Maria;Jaekel, Oliver
方法：采用已发表的EBT膜扫描方案。研究了未辐照和辐照EBT2薄膜的显色均匀性。测定了EBT2膜的剂量响应，并评价了膜的不均匀性对剂量测定的影响。结果：单片内像素值的不均匀性高达+/- 3.7%。发现相对不均匀性与剂量近似无关。薄膜响应的不均匀性导致了1 Gy +/- 8.7%剂量测定的不确定性。当使用净光密度进行剂量校准时，剂量测定的不确定度大于+/- 6%。结论：本研究中调查的批次EBT2薄膜显示出反应不均匀性，这导致剂量测定的不确定性超过了普遍接受的耐受水平。在临床常规使用该膜之前，进一步测试EBT2批次的均匀性是很重要的。
Methods: A scan protocol established for EBT film and published previously was used. The uniformity of the film coloration was investigated for unirradiated and irradiated EBT2 film sheets. The dose response of EBT2 film was measured and the influence of film inhomogeneities on dose determination was evaluated.Results: Inhomogeneities in pixel values of up to +/- 3.7% within one film were detected. The relative inhomogeneities were found to be approximately independent of the dose. Nonuniformities of the film response lead to uncertainties in dose determination of +/- 8.7% at 1 Gy. When using net optical densities for dose calibration, uncertainties in dose determination amount to more than +/- 6%.Conclusions: EBT2 films from the lot investigated in this study show response inhomogeneities, which lead to uncertainties in dose determination exceeding the commonly accepted tolerance levels. It is important to test further EBT2 lots regarding homogeneity before using the film in clinical routine.