Institute for Health Care Development, Sunway University, PJ, Malaysia.
Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
PLoS One. 2020 Jul 16;15(7):e0235053. doi: 10.1371/journal.pone.0235053. eCollection 2020.
Study has been made of the thermoluminescence yield of various novel tailor-made silica fibres, 6 and 8 mol % Ge-doped, with four differing outer dimensions, comprised of flat and cylindrical shapes, subjected to electron irradiation. Main thermoluminescence dosimetric characteristics have been investigated, including the glow curve, dose response, energy dependence, minimum detectable dose, effective atomic number, linearity of index and sensitivity of the fibres. The studies have also established the uncertainties involved as well as the stability of response in terms of fading effect, reproducibility and annealing. In addition, dose-rate dependence was accounted for as this has the potential to be a significant factor in radiotherapy applications. The 6 and 8 mol % fibres have been found to provide highly linear dose response within the range 1 to 4 Gy, the smallest size flat fibre, 6 mol% Ge-doped, showing the greatest response by a factor of 1.1 with respect to the highly popular LiF phosphor-based medium TLD100. All of the fibres also showed excellent reproducibility with a standard deviation of < 2% and < 4% for 6 and 8 mol % Ge-doped fibres respectively. For fading evaluation, the smallest 6 mol% Ge-doped dimension flat fibre, i.e., 85 × 270 μm displayed the lowest signal loss within 120 days post-irradiation, at around 26.9% also showing a response superior to that of all of the other fibres. Moreover, all the fibres and TLD-100 chips showed independence with respect to electron irradiation energy and dose-rate. Compared with the 8 mol% Ge-doped optical fibres, the 6 mol% Ge-doped flat optical fibres have been demonstrated to possess more desirable performance features for passive dosimetry, serving as a suitable alternative to TLD-100 for medical irradiation treatment applications.
研究了四种不同外尺寸的新型定制二氧化硅纤维的热释光产额，分别为 6 mol% 和 8 mol% 的掺锗，包括平面和圆柱形，它们都受到了电子辐照。主要的热释光剂量学特性已被研究，包括发光曲线、剂量响应、能量依赖性、最小可探测剂量、有效原子序数、指数线性度和纤维的灵敏度。研究还确定了所涉及的不确定度以及在褪色效应、重复性和退火方面的响应稳定性。此外，还考虑了剂量率依赖性，因为它有可能成为放射治疗应用中的一个重要因素。研究发现，6 mol% 和 8 mol% 的纤维在 1 到 4 Gy 的范围内提供了高度线性的剂量响应，最小尺寸的平面纤维，6 mol% 掺锗，相对于非常流行的基于 LiF 荧光粉的中 TLD100，其响应最大，增加了 1.1 倍。所有纤维的重复性也非常好，标准偏差分别小于 2%和 4%，对于 6 mol% 和 8 mol% 掺锗纤维。对于褪色评估，最小尺寸的 6 mol% 掺锗平面纤维，即 85×270 μm，在辐照后 120 天内显示出最低的信号损失，约为 26.9%，其响应也优于所有其他纤维。此外，所有纤维和 TLD-100 芯片都表现出对电子辐照能量和剂量率的独立性。与 8 mol% 掺锗光纤相比，6 mol% 掺锗平面光纤在被动剂量测量方面表现出更理想的性能特征，可作为 TLD-100 的替代物，用于医疗辐照治疗应用。
