The use of a reflective scanner to study radiochromic film response
The use of a reflective scanner to study radiochromic film response
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DOI：
10.1088/0031-9155/47/16/308
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发表时间：
2002-08-21
影响因子：
3.5
通讯作者：
Brandan, ME
中科院分区：
文献类型：
--
作者：
Alva, H;Mercado-Uribe, H;Brandan, ME
使用平板反射式 Microtek ScanMaker E3 扫描仪在不同条件下研究了 GafChromic MD-55-2 胶片响应，以优化其使用。使用 Co-60 伽马射线以 0-300 Gy 的剂量间隔进行照射，以产生校准的阶梯楔形。建议采用 24 位色标模式以及将图像分割为红色、绿色和蓝色分量，作为 256 灰度级（8 位）模式的改进剂量测定方法，从而扩展了该胶片的动态范围。评估了不同的胶片方向和定位、黑色或白色背景以及单独步骤的胶片扫描。通过在放射变色胶片附近添加参考黑白步骤来克服不需要的归一化，从而确保再现性。发现使用红色滤镜相当于使用图像分色后图像的红色分量。如果使用红色以外的颜色成分来评估响应，则 MD-55-2 薄膜的有用范围可扩展至 300 Gy。与光密度测量的比较表明，廉价的商用扫描仪可能是密度计的良好替代品。
GafChromic MD-55-2 film response was studied using a flatbed, reflective Microtek ScanMaker E3 scanner, under different conditions to optimize its use. Irradiations were performed using Co-60 gamma rays in a 0-300 Gy dose interval to produce a calibrated step wedge. A 24-bit colour-scale mode along with image splitting into its red, green and blue components is suggested as an improved dosimetry method over a 256 grey level (8-bit) mode, extending the dynamic range for this film. Diverse film orientation and positioning, a black or a white background, and individual step film scanning were evaluated. Unwanted normalization is overcome by adding reference black and white steps adjacent to the radiochromic film, ensuring reproducibility. The use of a red filter was found to be equivalent to the use of the red component of the image after image colour splitting. The useful range for MD-55-2 film is extended up to 300 Gy if colour components, other than red, are used to evaluate the response. Comparisons with optical density measurements show that inexpensive commercial scanners might be a good alternative to densitometers.