Evaluation of a 2D diode array for IMRT quality assurance
Evaluation of a 2D diode array for IMRT quality assurance
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DOI：
10.1016/j.radonc.2003.10.014
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发表时间：
2004-02-01
影响因子：
5.7
通讯作者：
Wong, JW
中科院分区：
文献类型：
--
作者：
Létourneau, D;Gulam, M;Wong, JW
背景与目的：调强放射治疗（IMRT）剂量学的质量保证是一项艰巨的任务。这项工作的目标是评估一个新的二维二极管阵列（MapCheck太阳核公司，墨尔本，佛罗里达）的剂量学特性，并评估它可以在常规调强放射治疗QA的作用。材料和方法：MapCheck的基本属性，如再现性，线性度和温度依赖性研究高能光子束。文中还对二极管灵敏度差的校正精度进行了评估。二极管阵列的基准对传统和调强放射治疗的电影和离子室。MapCheck对多叶准直器位置误差的灵敏度determined.Results：二极管阵列响应与剂量呈线性关系，最高可达295 cGy。所有二极管都校准到彼此的+/-1%以内，大多数在+/-0.5%以内。MapCheck读数可重现，最大SD为+/-0.15%。注意到0.57%/℃的温度依赖性，绝对剂量测定应考虑到这一点。MapCheck的相对和绝对剂量测定的临床性能与七束（6 MV）头颈部调强放射治疗计划证明，并比较以及与电影和离子室测量。比较计算的剂量maps表明，规划系统模型低估了剂量梯度在半影regions.Conclusions：MapCheck提供了所需的相对和绝对剂量测量的剂量测定特性。它在临床中的使用可以简化和减少调强放射治疗QA的工作量。(C)2003爱思唯尔爱尔兰有限公司保留所有权利。
Background and purpose: The QA of intensity modulated radiotherapy (IMRT) dosimetry is a laborious task. The goal of this work is to evaluate the dosimetric characteristics of a new 2D diode array (MapCheck from Sun Nuclear Corporation, Melbourne, Florida) and assess the role it can play in routine IMRT QA.Material and methods: Fundamental properties of the MapCheck such as reproducibility, linearity and temperature dependence are studied for high-energy photon beams. The accuracy of the correction for difference of diode sensitivity is also assessed. The diode array is benchmarked against film and ion chambers for conventional and IMRT treatments. The MapCheck sensitivity to multileaf collimator position errors is determined.Results: The diode array response is linear with dose up to 295 cGy. All diodes are calibrated to within +/-1% of each other, and mostly within +/-0.5%. The MapCheck readings are reproducible to within a maximum SD of +/-0.15%. A temperature dependence of 0.57%/degreesC was noted and should be taken into account for absolute dosimetric measurement. Clinical performance of the MapCheck for relative and absolute dosimetry is demonstrated with seven beam (6 MV) head and neck IMRT plans, and compares well with film and ion chamber measurements. Comparison to calculated dose maps demonstrates that the planning system model underestimates the dose gradients in the penumbra region.Conclusions: The MapCheck offers the dosimetric characteristics required for performing both relative and absolute dose measurements. Its use in the clinic can simplify and reduce the IMRT QA workload. (C) 2003 Elsevier Ireland Ltd. All rights reserved.