Absorption spectra variations of EBT radiochromic film from radiation exposure
Absorption spectra variations of EBT radiochromic film from radiation exposure
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DOI：
10.1088/0031-9155/50/13/n02
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发表时间：
2005-07-07
影响因子：
3.5
通讯作者：
Yu, PKN
中科院分区：
文献类型：
--
作者：
Butson, MJ;Cheung, T;Yu, PKN
Gafchromic EBT放射致变色胶片是一种最新的辐射诱导自动显影x射线分析胶片，可用于放射治疗中的放射剂量测定。研究了其在可见光波段的吸收特性，结果表明在636 nm和585 nm处有两个主要的吸收峰。这些吸收峰不同于许多其他放射变色薄膜产品，如Gafchromic MD-55和HS薄膜，其中两个峰分别位于676 nm和617 nm。吸收光谱的一般形状与旧的设计相似。在高能x射线中发现了更高的灵敏度，在636 nm使用6 MV x射线测量的第一个Gy内，OD的平均每Gy变化为0.6 OD。在6mv x射线能量下，HS薄膜在676 nm吸收峰处的第一Gy约为0.09 OD单位。这种胶片的蓝色在视觉上不同于老式的彩色胶片，胶片内的中档蓝色强度更高。该胶片为临床放疗x线评估提供了1 ~ 2 Gy剂量范围内的充分的相对吸收剂量测量，经进一步研究可用于分级放疗剂量评估。
Gafchromic EBT radiochromic film is one of the newest radiation-induced auto-developing x-ray analysis films available for therapeutic radiation dosimetry in radiotherapy applications. The spectral absorption properties in the visible wavelengths have been investigated and results show two main peaks in absorption located at 636 nm and 585 nm. These absorption peaks are different to many other radiochromic film products such as Gafchromic MD-55 and HS film where two peaks were located at 676 nm and 617 nm respectively. The general shape of the absorption spectra is similar to older designs. A much higher sensitivity is found at high-energy x-rays with an average 0.6 OD per Gy variation in OD seen within the first Gy measured at 636 nm using 6 MV x-rays. This is compared to approximately 0.09 OD units for the first Gy at the 676 nm absorption peak for HS film at 6 MV x-ray energy. The film's blue colour is visually different from older varieties of Gafchromic film with a higher intensity of mid-range blue within the film. The film provides adequate relative absorbed dose measurement for clinical radiotherapy x-ray assessment in the 1-2 Gy dose range which with further investigation may be useful for fractionated radiotherapy dose assessment.