Kaunas University of Technology, Kaunas, Lithuania.
Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania; Department of Radiology, Nuclear Medicine and Medical Physics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
Environ Res. 2020 Apr;183:109144. doi: 10.1016/j.envres.2020.109144. Epub 2020 Jan 18.
Reconstruction and analysis of low doses received by the occupationally exposed medical radiation workers, especially nuclear medicine staff dealing with radioisotopes may significantly contribute to the understanding of radiation impact on individuals, assess and predict radiation related risks for the development of cancer or other specific diseases.
A pool of 2059 annual effective doses corresponding to 272 job's positions occupied by nuclear medicine and radiology workers for a certain time period over 26 years in five Lithuanian hospitals was investigated in order to analyze the occupational exposure tendencies to medical staff. Requested data, measured in terms of whole body dose, personal dose equivalent Hp(10), was obtained from the National Register of Sources of Ionizing Radiation and Occupational Exposure. Considering that nuclear medicine staff is dealing with open sources/radioisotopes, doses to extremities, Hp(0.07), were measured using thermoluminescent dosimeters (TLD) of LiF:Mg, Ti type. Lifetime risk estimations for the development of specific cancer (thyroid cancer and leukemia) for exposed radiation workers were performed using risk models included in BEIR VII report (BEIR VII, 2006). The conservative assessment of the thyroid exposure was performed using RadRAT 4.1.1 tool.
Doses to radiology technologists and radiology nurses were found to be highest over the years. However, their annual doses never exceeded dose limit of 20 mSv and were following the same decreasing tendency as the doses of other personnel. There was no increase of doses to nuclear medicine staff observed after installation of two new PET/CT machines, indicating increased radiation protection culture and application of relevant technical and protective measures by the staff. Measured fingertip doses were 2-3 times higher than the hand doses measured with TLD ring and were dependent on the type and frequency of the nuclear medicine examination procedure and on the type and activity of isotopes used for examination.
For the first time, retrospective dose evaluation for the cohort of medical radiation workers was performed in the country. It enabled estimation of lifetime attributable risk for the development of two cancer types: thyroid and leukemia cancer among occupationally exposed medical radiation staff. Projected risk was low, ~10, however it was found that the risk of thyroid cancer for female staff was 5.7 times higher than for the males. Obtained results will be used for the predictive assessment of possible radiation induced health effects to occupationally exposed medical radiation workers.
重建和分析职业暴露于医疗辐射的医学放射工作人员，特别是处理放射性同位素的核医学工作人员所接受的低剂量，可能对理解辐射对个体的影响、评估和预测辐射相关风险以发展癌症或其他特定疾病有重要贡献。
对 5 家立陶宛医院 26 年期间 272 个核医学和放射科工作人员职位的 2059 名年度有效剂量进行了调查，以分析医疗工作人员的职业暴露趋势。全身剂量、个人剂量当量 Hp(10)等方面的数据是从国家电离源登记册和职业暴露登记册中获取的。由于核医学工作人员处理开放源/放射性同位素，因此使用 LiF:Mg、Ti 型热释光剂量计（TLD）测量四肢剂量 Hp(0.07)。使用 BEIR VII 报告（BEIR VII，2006 年）中包含的风险模型对暴露于辐射的工作人员发生特定癌症（甲状腺癌和白血病）的终生风险进行了估计。使用 RadRAT 4.1.1 工具对甲状腺暴露进行保守评估。
多年来，放射科技术员和放射科护士的剂量最高。然而，他们的年剂量从未超过 20 mSv 的剂量限值，且呈与其他人员相同的下降趋势。在安装两台新的 PET/CT 机器后，并未观察到核医学工作人员的剂量增加，这表明辐射防护文化有所提高，工作人员应用了相关技术和防护措施。指尖剂量比 TLD 环测量的手部剂量高 2-3 倍，且取决于核医学检查程序的类型和频率，以及用于检查的同位素的类型和活度。
首次在该国对医疗放射工作人员的队列进行了回顾性剂量评估。它能够估计两种癌症类型（甲状腺癌和白血病）在职业暴露于医疗辐射的工作人员中的终生归因风险。预计风险较低，约为 10，但发现女性工作人员的甲状腺癌风险比男性高 5.7 倍。获得的结果将用于预测职业暴露于医疗辐射的工作人员可能受到的辐射诱发健康影响。
