Santos Alexandre M Caraça, Mohammadi Mohammad, Afshar V Shahraam
Department of Medical Physics, Royal Adelaide Hospital, Adelaide 5000, Australia and Institute for Photonics and Advanced Sensing, School of Physical Sciences, University of Adelaide, Adelaide 5005, Australia.
Department of Medical Physics, Royal Adelaide Hospital, Adelaide 5000, Australia and Department of Medical Physics, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan 65167-3-8736, Iran.
Med Phys. 2015 Nov;42(11):6349-56. doi: 10.1118/1.4931968.
The authors evaluate the capability of a beryllium oxide (BeO) ceramic fiber-coupled luminescence dosimeter, named radioluminescence/optically stimulated luminescence (RL/OSL) BeO FOD, for dosimetric verification of high dose rate (HDR) treatments. The RL/OSL BeO FOD is capable of RL and OSL measurements.
The RL/OSL BeO FOD is able to be inserted in 6F proguide needles, used in interstitial HDR treatments. Using a custom built Perspex phantom, 6F proguide needles could be submerged in a water tank at 1 cm separations from each other. A second background fiber was required to correct for the stem effect. The stem effect, dose linearity, reproducibility, depth-dose curves, and angular and temperature dependency of the RL/OSL BeO FOD were characterised using an Ir-192 source. The RL/OSL BeO FOD was also applied to the commissioning of a 10 mm horizontal Leipzig applicator.
Both the RL and OSL were found to be reproducible and their percentage depth-dose curves to be in good agreement with those predicted via TG-43. A combined uncertainty of 7.9% and 10.1% (k=1) was estimated for the RL and OSL, respectively. For the 10 mm horizontal Leipzig applicator, measured percentage depth doses were within 5% agreement of the published reference calculations. The output at the 3 mm prescription depth for a 1 Gy delivery was verified to be 0.99±0.08 Gy and 1.01±0.10 Gy by the RL and OSL, respectively.
The use of the second background fiber under the current setup means that the two fibers cannot fit into a single 6F needle. Hence, use of the RL is currently not adequate for the purpose of in vivo brachytherapy dosimetry. While not real-time, the OSL is shown to be adequate for in vivo brachytherapy dosimetry.
作者评估一种名为放射性发光/光激励发光（RL/OSL）氧化铍（BeO）光纤耦合发光剂量计用于高剂量率（HDR）治疗剂量验证的能力。RL/OSL BeO FOD能够进行RL和OSL测量。
RL/OSL BeO FOD能够插入用于组织间HDR治疗的6F前导针中。使用定制的有机玻璃体模，6F前导针可以彼此间隔1 cm浸没在水箱中。需要第二根本底光纤来校正茎效应。使用铱-192源对RL/OSL BeO FOD的茎效应、剂量线性、重复性、深度剂量曲线以及角度和温度依赖性进行了表征。RL/OSL BeO FOD还应用于10 mm水平莱比锡施源器的调试。
发现RL和OSL均可重复，其百分深度剂量曲线与通过TG-43预测的曲线吻合良好。RL和OSL的合成不确定度分别估计为7.9%和10.1%（k=1）。对于10 mm水平莱比锡施源器，测量的百分深度剂量与已发表的参考计算结果在5%的范围内一致。通过RL和OSL验证，在1 Gy剂量输送时，3 mm处方深度处的输出分别为0.99±0.08 Gy和1.01±0.10 Gy。
在当前设置下使用第二根本底光纤意味着两根光纤无法装入单个6F针中。因此，目前RL用于体内近距离治疗剂量测定的目的还不够充分。虽然不是实时的，但OSL被证明适用于体内近距离治疗剂量测定。
