Radiological Sciences Department, Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil.
Radiological Sciences Department, Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil; Physics Department, Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil.
Phys Med. 2021 Apr;84:214-219. doi: 10.1016/j.ejmp.2021.02.027. Epub 2021 Mar 19.
Cobalt-60 irradiators and soft X-ray machines are frequently used for research purposes, but the dosimetry is not always performed using the recommended protocols. This may lead to confusing and untrustworthy results within the conducted research. Postal dosimetry systems have already been approved by the IAEA, with thermoluminescence dosimeters (TLD) and optically stimulated luminescence (OSL) as the most commonly used dosimeter systems in these cases. The present study tests the Fricke dosimeter properties as a potential system to be used in postal dosimetry for a project using research irradiators. The Fricke solution was prepared according to the literature, and the linearity and fading tests were performed accordingly. All calculated doses were measured using a NE2571 Farmer ionization chamber as a reference. Doses ranging from 25 to 300 Gy were delivered by a research irradiator, with 150 kV and 22 mA to the Fricke solutions inside polyethylene (PE) bags (4 × 4 × 0.2 cm). The results compared with the ionization chamber showed a linear response to the range of doses used. Fading tests showed no significant difference for the absorbed doses over 9 days, with a maximum difference of 1.5% found between days 0 and 3. The Fricke dosimeter presented good linearity, for low and high doses, and low uncertainties for the fading even for 9 days after irradiation. These preliminary results are motivating, and as the next step, we intend to design a postal dosimetry system using the PE bags of Fricke solution.
钴-60 辐照器和软 X 射线机常用于研究目的，但剂量测定并不总是按照推荐的方案进行。这可能会导致研究结果混乱和不可信。邮政剂量计系统已经得到国际原子能机构的批准，在这些情况下，热释光剂量计 (TLD) 和光激励发光 (OSL) 是最常用的剂量计系统。本研究测试了 Fricke 剂量计作为一种潜在的邮政剂量计系统的特性，用于一个使用研究辐照器的项目。Fricke 溶液是根据文献制备的，并进行了相应的线性和褪色测试。所有计算出的剂量都使用 NE2571 Farmer 电离室作为参考进行测量。研究辐照器以 150 kV 和 22 mA 的剂量对聚乙烯 (PE) 袋内的 Fricke 溶液（4×4×0.2 cm）进行了 25 至 300 Gy 的剂量照射。与电离室相比，结果显示出对所使用剂量范围的线性响应。褪色测试表明，在 9 天内，吸收剂量没有显著差异，在第 0 天和第 3 天之间发现最大差异为 1.5%。Fricke 剂量计在低剂量和高剂量下表现出良好的线性，即使在辐照后 9 天，褪色的不确定度也很低。这些初步结果令人鼓舞，下一步我们打算使用 Fricke 溶液的 PE 袋设计一个邮政剂量计系统。
