In the case of a radiological or nuclear event, biological dosimetry can be an important tool to support clinical decision-making. During a nuclear event, individuals might be exposed to a mixed field of neutrons and photons. The composition of the field and the neutron energy spectrum influence the degree of damage to the chromosomes. During the transatlantic BALANCE project, an exposure similar to a Hiroshima-like device at a distance of 1.5 km from the epicenter was simulated and biological dosimetry based on dicentric chromosomes was performed to evaluate the participants ability to discover unknown doses and to test the influence of differences in neutron spectra. In a first step, calibration curves were established by irradiating blood samples with 5 doses in the range of 0 Gy to 4 Gy at two different facilities in Germany (PTB) and USA (CINF). The samples were sent to eight participating laboratories from the RENEB network and dicentric chromosomes were scored by each participant. Next, blood samples were irradiated with 4 blind doses in each of the two facilities and sent to the participants to provide dose estimates based on the established calibration curves. Manual and semi-automatic scoring of dicentric chromosomes were evaluated for their applicability to neutron exposures. Moreover, the biological effectiveness of the neutrons from the two irradiation facilities was compared. The calibration curves from samples irradiated at CINF showed a 1.4 times higher biological effectiveness compared to samples irradiated at PTB. For manual scoring of dicentric chromosomes, the doses of the test samples were mostly successfully resolved based on the calibration curves established during the project. For semi-automatic scoring, the dose estimation for the test samples was less successful. Doses >2 Gy in the calibration curves revealed non-linear associations between dose and dispersion index of the dicentric counts, especially for manual scoring. The differences in the biological effectiveness between the irradiation facilities suggested that the neutron energy spectrum can have a strong impact on the dicentric counts.


中文翻译：

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作为 BALANCE 项目的一部分，在两个辐照设施中进行中子照射后生物剂量测定的国际比较练习

在发生放射或核事件的情况下，生物剂量测定可以成为支持临床决策的重要工具。在核事件期间，个人可能会暴露在中子和光子的混合场中。场的组成和中子能谱影响染色体的损伤程度。在跨大西洋BALANCE项目中，在距震中1.5公里处模拟类似广岛装置的暴露，并进行基于双着丝粒染色体的生物剂量测定，以评估参与者发现未知剂量的能力并测试未知剂量的影响中子谱的差异。第一步，通过在德国 (PTB) 和美国 (CINF) 的两个不同设施用 0 Gy 至 4 Gy 范围内的 5 个剂量照射血液样本来建立校准曲线。这些样本被送到 RENEB 网络的八个参与实验室，每个参与者对双着丝粒染色体进行评分。接下来，在两个设施中分别对血液样本进行 4 次盲剂量照射，并将其发送给参与者，以根据建立的校准曲线提供剂量估计。评估双着丝粒染色体的手动和半自动评分对中子暴露的适用性。此外，还比较了两个辐照设施中子的生物有效性。CINF 辐照样品的校准曲线显示，与 PTB 辐照样品相比，生物有效性高 1.4 倍。对于双着丝粒染色体的手动评分，测试样品的剂量大多根据项目期间建立的校准曲线成功解决。对于半自动评分，测试样本的剂量估计不太成功。校准曲线中 >2 Gy 的剂量揭示了双着丝粒计数的剂量和分散指数之间的非线性关联，特别是对于手动评分。辐照设施之间生物有效性的差异表明中子能谱对双着丝粒计数有很大影响。