Characterization and real-time optical measurements of the ionizing radiation dose response for a new radiochromic medium
Characterization and real-time optical measurements of the ionizing radiation dose response for a new radiochromic medium
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DOI：
10.1118/1.1951447
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发表时间：
2005-08-01
期刊：
影响因子：
3.8
通讯作者：
Jaffray, DA
中科院分区：
文献类型：
--
作者：
Rink, A;Vitkin, IA;Jaffray, DA
研究了一种新型辐射变色薄膜GafChromic EBT，用于实时辐射剂量测定系统。它被发现对电离辐射剂量的敏感性约为8倍，表现出更少的暴露后发展，并比其前身GafChromic MD-55更快地实现稳定的读出。观察到暴露和暴露后的光密度变化有明显区别，但暴露期间获得的测量值与时间或剂量不呈线性关系。这不能用吸光度最大变化的波长偏移来解释，因为在整个暴露范围（高达9.52戈伊）内，吸光度在636 nm附近保持稳定。增加感兴趣的光谱窗口进行计算没有什么纠正的非线性。的辐射变色膜表现出小的剂量率依赖性，在实时测量中，在光密度测量的变化的标准偏差从0.9%增加到1.8%，超过六倍的剂量率变化。总的来说，GafChromic EBT提高了灵敏度，减少了照射后变暗，这预示着它作为辐射剂量计的潜在作用，包括实时应用。(c)2005年美国医学物理学家协会。
A new radiochromic film, GafChromic EBT, was investigated for use in a real-time radiation dosimetry system. It was found to be approximately eight times more sensitive to ionizing radiation dose, exhibited less postexposure development and achieved stable readout faster than one of its predecessors, GafChromic MD-55. A clear distinction in change in optical density between exposure and postexposure was observed, but the measurements obtained during exposure were not linear with time or dose. This could not be explained by a shift in wavelength of maximum change in absorbance, as it was stable at similar to 636 nm during the entire exposure range (up to 9.52 Gy). Increasing the spectral window of interest over which calculations were performed did little to correct the nonlinearity. The radiochromic film exhibited small dose rate dependence in real-time measurements, with an increase in standard deviation of change in optical density measurements from 0.9% to 1.8% over a sixfold variation in dose rate. Overall, GafChromic EBT has increased sensitivity and decreased postexposure darkening, and this bodes well for its potential role as a radiation dosimeter, including real-time applications. (c) 2005 American Association of Physicists in Medicine.