Application of radiochromic gel dosimetry to commissioning of a megavoltage research linear accelerator for small-field animal irradiation studies.
Application of radiochromic gel dosimetry to commissioning of a megavoltage research linear accelerator for small-field animal irradiation studies.
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辐射变色凝胶剂量测定法在兆伏研究用直线加速器小野动物辐照研究中的应用。
DOI：
10.1002/mp.14685
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发表时间：
2021-03
期刊：
影响因子：
3.8
通讯作者：
El Naqa I
中科院分区：
文献类型：
--
作者：
Ba Sunbul N;Oraiqat I;Rosen B;Miller C;Meert C;Matuszak MM;Clarke S;Pozzi S;Moran JM;El Naqa I
开发并实施一种高效、准确的调试程序，用于MV研究型直线加速器（Linatron-M9）的小野静态射束动物辐照研究（使用放射性铬凝胶剂量测定法）。研究用直线加速器（Linatron-M9）是一台9 MV直线加速器，其静态固定准直器开口直径为5.08 cm。手动放置电极导线准直器，以创建2x2 cm 2、1x 1 cm 2和0.5x0.5 cm 2的较小射野。使用各种剂量测定工具（包括小体积电离室（A14）、GAFCHROMIC™ EBT 3薄膜和Clearview凝胶剂量计）进行相对剂量测定测量，包括剖面、深度剂量百分比（PDD）曲线、射束发散度和相对输出因子。凝胶剂量计用于提供照射野的3D体积参考。在2 cm的参考深度处提取Linatron曲线和相对输出因子，其中输出因子相对于2x2 cm 2参考场进行测量。使用A-14电离室测量进行绝对剂量测定，并使用国家标准实验室远程剂量测定服务进行验证。确认绝对剂量测定测量值在1.4%范围内（k = 2，95%置信度= 5%）。使用薄膜和凝胶测量的小视野的相对输出因子与两种方法之间的最大相对误差百分比差异一致，对于1x 1 cm 2视野为1.1%，对于0.5x0.5 cm 2视野为4.3%。这些相对误差主要是由于准直器定位的可变性。测量的光束轮廓显示出与光束尺寸（测量为FWHM）的良好一致性，在约0.8 mm（或更小）内。薄膜测量更准确的半影区，由于薄膜的更精细的分辨率相比，凝胶剂量计。根据货车Dyk标准，薄膜和凝胶测量的PDD值在从0.5 cm深度开始的累积区域内一致性在11%以内，在超过最大剂量并进入深度达5 cm的下降区域内一致性在2.6%以内。对于0.5x0.5 cm 2和1x 1 cm 2射野，所有区域的2D射束轮廓等剂量线均在0.5 mm范围内，对于2x2 cm 2的较大射野，在1 mm范围内。对于1x 1 cm 2和2x2 cm 2射野，2D PDD曲线在典型治疗区域（1-4 cm）最大值的约2%内一致，对于0.5x0.5 cm 2射野，在5%内一致。这项工作提供了一个调试过程，以测量束流特性的固定束MV加速器与详细的剂量学评价其实施兆伏级小动物辐照研究。辐射变色凝胶剂量计是一种高效的小视场相对剂量测量工具，可提供3D剂量测量，允许全面代表剂量、剂量计未对准校正和高再现性以及低剂量计间变异性。总的来说，辐射变色凝胶是有价值的快速，完整的相对剂量学调试相比，在高能量小野动物辐照研究中的应用程序的电影。
To develop and implement an efficient and accurate commissioning procedure for small field static beam animal irradiation studies on an MV research linear accelerator (Linatron-M9) using radiochromic gel dosimetry. The research linear accelerator (Linatron-M9) is a 9 MV linac with a static fixed collimator opening of 5.08 cm diameter. Lead collimators were manually placed to create smaller fields of 2x2 cm2, 1x1 cm2 and 0.5x0.5 cm2. Relative dosimetry measurements were performed, including profiles, percent depth dose (PDD) curves, beam divergence, and relative output factors using various dosimetry tools, including a small volume ionization chamber (A14), GAFCHROMIC™ EBT3 film, and Clearview gel dosimeters. The gel dosimeter was used to provide a 3D volumetric reference of the irradiated fields. The Linatron profiles and relative output factors were extracted at a reference depth of 2 cm with the output factor measured relative to the 2x2 cm2 reference field. Absolute dosimetry was performed using A-14 ionization chamber measurements, which were verified using a national standards laboratory remote dosimetry service. Absolute dosimetry measurements were confirmed within 1.4% (k = 2, 95% confidence = 5%). The relative output factor of the small fields measured with films and gels agreed with a maximum relative percent error difference between the two methods of 1.1 % for the 1x1 cm2 field and 4.3 % for the 0.5x0.5 cm2 field. These relative errors were primarily due to the variability in the collimator positioning. The measured beam profiles demonstrated excellent agreement for beam size (measured as FWHM), within approximately 0.8 mm (or less). Film measurements were more accurate in the penumbra region due to the film’s finer resolution compared with the gel dosimeter. Following the van Dyk criteria, the PDD values of the film and gel measurements agree within 11% in the buildup region starting from 0.5 cm depth and within 2.6 % beyond maximum dose and into the fall-off region for depths up to 5 cm. The 2D beam profile isodose lines agree within 0.5 mm in all regions for the 0.5x0.5 cm2 and the 1x1 cm2 fields and within 1 mm for the larger field of 2x2 cm2. The 2D PDD curves agree within approximately 2% of the maximum in the typical therapy region (1–4 cm) for the 1x1 cm2 and 2x2 cm2 and within 5% for the 0.5x0.5 cm2 field. This work provides a commissioning process to measure the beam characteristics of a fixed beam MV accelerator with detailed dosimetric evaluation for its implementation in megavoltage small animal irradiation studies. Radiochromic gel dosimeters are efficient small field relative dosimetry tools providing 3D dose measurements allowing for full representation of dose, dosimeter misalignment corrections and high reproducibility with low inter-dosimeter variability. Overall, radiochromic gels are valuable for fast, full relative dosimetry commissioning in comparison to films for application in high energy small-field animal irradiation studies.
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影响因子：
3.5
作者：
Butson, MJ;Cheung, T;Yu, PKN
通讯作者：
Yu, PKN
影响因子：
3.8
作者：
Almond, PR;Biggs, PJ;Rogers, DWO
通讯作者：
Rogers, DWO
DOI：
10.1016/j.ejmp.2018.07.002
发表时间：
2018-08-01
影响因子：
3.4
作者：
Colnot, J.;Huet, C.;Clairand, I
通讯作者：
Clairand, I
影响因子：
3.8
作者：
Cho, Nathan;Tsiamas, Panagiotis;Wong, John
通讯作者：
Wong, John
聚合物凝胶剂量测定。
影响因子：
3.5
作者：
Baldock C;De Deene Y;Doran S;Ibbott G;Jirasek A;Lepage M;McAuley KB;Oldham M;Schreiner LJ
通讯作者：
Schreiner LJ