Characterization of three solid state dosimetry systems for use in high energy photon dosimetry audits in radiotherapy
Characterization of three solid state dosimetry systems for use in high energy photon dosimetry audits in radiotherapy
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DOI：
10.1016/j.radmeas.2017.04.017
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发表时间：
2017-11-01
影响因子：
2
通讯作者：
Izewska, Joanna
中科院分区：
文献类型：
--
作者：
Wesolowska, Paulina Elzbieta;Cole, Andrew;Izewska, Joanna
国际原子能机构剂量测定实验室（DOL）的目标是通过提供高能光子束的独立远程审计来提高世界各地医院临床剂量测定的准确性。DOL使用热释光剂量测定系统提供审计服务已超过47年。两个附加系统：光学受激发光剂量测定（OSLD）系统和无线电光致发光剂量测定（RPLD）系统经历调试过程。对系统的参数、阅读方法和剂量学特性进行了研究和比较，建立并优化了各系统的读出程序。研究了剂量学特性，如重复性、照射后信号随时间的衰减、信号/剂量依赖性和能量响应。对RPLD和OSLD进行了额外的测试，以检查每个读数的信号损耗和剂量计的个体灵敏度，并检查了RPLD系统的阅读位置依赖性。一个剂量计的4个读数的再现性对于TLD为0.48%，对于OSLD为0.16%，对于RPLD为0.15%。100天后的褪色效果为4%，OSLD为2%，RPLD为0.4%。TLD和RPLD的能量响应是相当的，发现OSLD的校正更高。在研究的剂量范围（1-4戈伊）内，RPLD剂量-反应为亚线性，而RPLD和OSLD反应为超线性。重复阅读过程是破坏性的，但是OSLD和RPLD可以重复读取，并且每次阅读的信号损耗对于OSLD为0.036%，对于RPLD为0.017%。RPLD和OSLD的灵敏度校正因子的确定与响应的标准偏差为2.2%的OSLD和0.9%的RPLD的1000剂量计。合并的标准不确定度（k=1）为TLD的1.60%，OSLD的1.46%和RPLD的1.51%。如果对所有描述的影响进行校正，则所有三个系统都可以成功地用于审计目的。(C)2017作者爱思唯尔有限公司出版
The IAEA Dosimetry Laboratory (DOL) aims to improve the accuracy of clinical dosimetry in hospitals world-wide by providing independent remote audits for high energy photon beams. A thermoluminescent dosimetry (TLD) system has been used by the DOL to provide audit services for over 47 years. Two additional systems: an optically stimulated luminescent dosimetry (OSLD) system and a radiophoto luminescent dosimetry (RPLD) system underwent a commissioning process. The systems' parameters, reading methodology and the dosimetric characteristics were investigated and compared.The read-out procedure for each system was established and optimized. Dosimetric characteristics such as reproducibility, signal fading with time after irradiation, signal per dose dependence and energy response were investigated. Additional tests to check signal depletion per readout and individual sensitivities of dosimeters were performed for RPLDs and OSLDs and also reading position dependence for the RPLD system was checked.The reproducibility of 4 readings of one dosimeter is 0.48% for TLDs, 0.16% for OSLDs and 0.15% for RPLDs. The fading effect after 100 days was 4% for TLD, 2% for OSLD and 0.4% for RPLD. Energy response of TLDs and RPLDs is comparable, higher corrections were found for OSLDs. The RPLD dose-response is sub linear whereas TLD and OSLD response is supra-linear at the dose range under study (1-4 Gy). The TLD reading procedure is destructive but OSLDs and RPLDs can be read repeatedly and the signal depletion per reading is 0.036% for OSLDs and 0.017% for RPLDs. The sensitivity correction factors for RPLDs and OSLDs were determined with the standard deviation in response of 1000 dosimeters of 2.2% for OSLD and 0.9% for RPLD. The combined standard uncertainties (k=1) are 1.60% for TLDs, 1.46% for OSLDs and 1.51% for RPLDs.All three systems can be successfully used for auditing purposes if corrections for all described effects are applied. (C) 2017 The Authors. Published by Elsevier Ltd.