Radiation hardness of the storage phosphor europium doped potassium chloride for radiation therapy dosimetry.
Radiation hardness of the storage phosphor europium doped potassium chloride for radiation therapy dosimetry.
复制标题
用于放射治疗剂量测定的存储磷铕掺杂氯化钾的辐射硬度。
DOI：
10.1118/1.3611043
复制
发表时间：
2011
期刊：
影响因子：
3.8
通讯作者：
Li,HHarold
中科院分区：
文献类型：
--
作者：
Driewer,JosephP;Chen,Haijian;Osvet,Andres;Low,DanielA;Li,HHarold
目的：可重复使用剂量计的一个重要特性是它的辐射硬度，即它在辐照后保持其剂量学优点的能力。本文研究了近年来提出的一种用于放射治疗剂量学的存储荧光粉材料——掺铕氯化钾（KCl:Eu2+）的辐射硬度。方法：本研究自制了直径6 mm、厚度1 mm的颗粒式KCl:Eu2+剂量计。用6 MV光子束或高剂量率137cs辐照器照射微球。利用实验室光致发光（PSL）读出系统研究了该材料的辐射灵敏度、剂量响应线性度和信号稳定性等宏观特性。由于荧光粉的性能与宿主晶格中的存储中心和活化剂Eu2+的状态有关，因此进行了光谱和时间测量，以便在微观水平上探索辐射引起的变化。结果：KCl:Eu2+剂量计在5000 Gy剂量史后保留了约90%的初始信号强度。剂量效应在100-700 Gy剂量范围内呈超线性，60 Gy后呈线性。在本研究跨越的0-5000 Gy剂量史中，线性关系没有显著变化。退火高剂量历史芯片导致超线性的回归和灵敏度的恢复。PSL的激发光谱、发射光谱、光致发光光谱和发光寿命均无显著变化，表明辐照后PSL信号过程保持完整，但由于可修复的辐射引起的晶格扰动而降低了效率。结论：对KCl:Eu2+材料的系统研究对于了解如何优化该材料用于放射治疗剂量学目的非常重要。本文的数据表明，KCl:Eu2+具有很强的辐射硬度，为进一步研究这种新材料提供了支持。
Purpose: An important property of a reusable dosimeter is its radiation hardness, that is, its ability to retain its dosimetric merits after irradiation. The radiation hardness of europium doped potassium chloride (KCl:Eu2+), a storage phosphor material recently proposed for radiation therapy dosimetry, is examined in this study.Methods: Pellet‐style KCl:Eu2+dosimeters, 6 mm in diameter, and 1 mm thick, were fabricated in‐house for this study. The pellets were exposed by a 6 MV photon beam or in a high dose rate137Cs irradiator. Macroscopic properties, such as radiation sensitivity, dose response linearity, and signal stability, were studied with a laboratory photostimulated luminescence (PSL) readout system. Since phosphor performance is related to the state of the storage centers and the activator, Eu2+, in the host lattice, spectroscopic and temporal measurements were carried out in order to explore radiation‐induced changes at the microscopic level.Results: KCl:Eu2+dosimeters retained approximately 90% of their initial signal strength after a 5000 Gy dose history. Dose response was initially supralinear over the dose range of 100–700 cGy but became linear after 60 Gy. Linearity did not change significantly in the 0–5000 Gy dose history spanned in this study. Annealing high dose history chips resulted in a return of supralinearity and a recovery of sensitivity. There were no significant changes in the PSL stimulation spectra, PSL emission spectra, photoluminescence spectra, or luminescence lifetime, indicating that the PSL signal process remains intact after irradiation but at a reduced efficiency due to reparable radiation‐induced perturbations in the crystal lattice.Conclusions: Systematic studies of KCl:Eu2+material are important for understanding how the material can be optimized for radiation therapy dosimetry purposes. The data presented here indicate that KCl:Eu2+exhibits strong radiation hardness and lends support for further investigations of this novel material.