Wu J M, Chen C S, Lan R H
Department of Radiation Oncology, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, R.O.C.
Changgeng Yi Xue Za Zhi. 1993 Jun;16(2):111-9.
Conventional use of Thermoluminescence (TL) in radiation dosimetry is very time-consuming. It requires repeating the procedures of preheating and annealing. In an attempt to simplify these procedures, we conducted an experiment of non-annealing TL dosimetry. This article reports the experiment's results. We adopted Lithium Fluoride (LiF) chip (TLD-100) in polystyrene under the exposure of Co-60, and the result was taken by HAR-SHAW-4000 TL reading system. The TL response was analyzed, including linearity, reproducibility and fading test. Because non-annealing TL response was greatly influenced by residual electron, TLD calibration curves were separated into two parts: (1) high dose region (HDR, 50-1500 cGy); (2) low dose region (LDR, 0-50 cGy). When TL dosimeters were exposed to a single high does (about 500 cGy), the HDR could be reproduced within 3% and fit a good linearity. For LDR, we had to give up the tail of glow curve in the high temperature region. We could then get good linearity and reproducibility. Furthermore, fading of non-annealing was apparently larger than annealing. We could control the fading of non-annealing was apparently larger than annealing. We could control the fading influence within 1% by taking the TL reading one hour after exposure. On the other hand, a combination of photon and electron exposure was also performed by non-annealing TL dosimetry. The results were compatible with Co-60 exposure in the same system.
热释光(TL)在辐射剂量测定中的传统应用非常耗时。它需要重复预热和退火的程序。为了简化这些程序,我们进行了非退火热释光剂量测定实验。本文报告了该实验的结果。我们采用了置于聚苯乙烯中的氟化锂(LiF)芯片(TLD - 100),在钴 - 60照射下,结果由HAR - SHAW - 4000热释光读数系统获取。对热释光响应进行了分析,包括线性、重复性和衰退测试。由于非退火热释光响应受残余电子的影响很大,热释光剂量计校准曲线被分为两部分:(1)高剂量区域(HDR,50 - 1500 cGy);(2)低剂量区域(LDR,0 - 50 cGy)。当热释光剂量计暴露于单次高剂量(约500 cGy)时,高剂量区域的结果可在3%以内重现,且具有良好的线性。对于低剂量区域,我们不得不舍弃高温区域的发光曲线尾部。然后我们可以得到良好的线性和重复性。此外,非退火的衰退明显大于退火的情况。我们可以通过在暴露后一小时读取热释光来将非退火的衰退影响控制在1%以内。另一方面,还通过非退火热释光剂量测定法进行了光子和电子照射的组合。结果与同一系统中钴 - 60照射的结果相符。