LiF:Mg,Ti TLD response as a function of photon energy for moderately filtered x-ray spectra in the range of 20-250 kVp relative to 60Co
LiF:Mg,Ti TLD response as a function of photon energy for moderately filtered x-ray spectra in the range of 20-250 kVp relative to 60Co
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DOI：
10.1118/1.2898137
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发表时间：
2008-05-01
期刊：
影响因子：
3.8
通讯作者：
DeWerd, L. A.
中科院分区：
文献类型：
--
作者：
Nunn, A. A.;Davis, S. D.;DeWerd, L. A.
LiF:Mg,Ti 热释光剂量计 (TLD) 的响应作为光子能量的函数，通过使用能量范围为 20-250 kVp 的适度过滤的 X 射线束照射来确定，相对于 Co-60 光子照射的响应。为了确定是否可以使用蒙特卡罗 (MC) 模拟等计算来预测每单位空气比释动能的 LiF:Mg,Ti TLD 的相对光输出作为光子能量的函数，将 X 射线束照射的测量结果与 MC 计算结果进行比较，类似于 Davis [Radiat.普罗特。多西姆。 106, 33-43 (2003)]。 TLD 使用美国国家标准与技术研究所可追踪的 M 系列 X 射线束（20-250 kVp 范围内）以众所周知的空气比释动速率进行光子束照射。对于每个 X 射线束，几组 TLD 被照射了对应于不同空气比释动能水平的时间，以考虑任何剂量非线性。然后将 TLD 光输出与使用 Co-60 辐照器在类似的相应空气比释动能水平下辐照的几组 TLD 的光输出进行比较。 MC 代码 MCNP5 用于考虑支架和 TLD 中的光子散射和衰减，并用于计算每个实验使用的光子束照射的每单位空气比释动能的预测相对 TLD 光输出。测得的相对 TLD 响应作为光子能量的函数，与 MC 计算结果相差高达 13%。我们得出的结论是，MC 计算不能准确预测 TLD 作为光子能量函数的相对响应，这与 Davis [Radiat.普罗特。多西姆。 106, 33-43 (2003)]。这可能是由于热释光过程的固态物理学的复杂性未纳入模拟中。 (C) 2008 年美国医学物理学家协会。
The response of LiF:Mg,Ti thermoluminescent dosimeters (TLDs) as a function of photon energy was determined using irradiations with moderately filtered x-ray beams in the energy range of 20-250 kVp relative to the response to irradiations with Co-60 photons. To determine if the relative light output from LiF:Mg,Ti TLDs per unit air kerma as a function of photon energy can be predicted using calculations such as Monte Carlo (MC) simulations, measurements from the x-ray beam irradiations were compared with MC calculated results, similar to the methodology used by Davis [Radiat. Prot. Dosim. 106, 33-43 (2003)]. TLDs were irradiated in photon beams with well-known air kerma rates using the National Institute of Standards and Technology traceable M-series x-ray beams in the range of 20-250 kVp. For each x-ray beam, several sets of TLDs were irradiated for times corresponding to different air kerma levels to take into account any dose nonlinearity. TLD light output was then compared to that from several sets of TLDs irradiated at similar corresponding air kerma levels using a Co-60 irradiator. The MC code MCNP5 was used to account for photon scatter and attenuation in the holder and TLDs and was used to calculate the predicted relative TLD light output per unit air kerma for irradiations with each of the experimentally used photon beams. The measured relative TLD response as a function of photon energy differed by up to 13% from the MC calculations. We conclude that MC calculations do not accurately predict the relative response of TLDs as a function of photon energy, consistent with the conclusions of Davis [Radiat. Prot. Dosim. 106, 33-43 (2003)]. This is likely due to complications in the solid state physics of the thermoluminescence process that are not incorporated into the simulation. (C) 2008 American Association of Physicists in Medicine.