Abstract

Purpose

In case of a mass-casualty radiological event, there would be a need for networking to overcome surge limitations and to quickly obtain homogeneous results (reported aberration frequencies or estimated doses) among biodosimetry laboratories. These results must be consistent within such network. Inter-laboratory comparisons (ILCs) are widely accepted to achieve this homogeneity. At the European level, a great effort has been made to harmonize biological dosimetry laboratories, notably during the MULTIBIODOSE and RENEB projects. In order to continue the harmonization efforts, the RENEB consortium launched this intercomparison which is larger than the RENEB network, as it involves 38 laboratories from 21 countries. In this ILC all steps of the process were monitored, from blood shipment to dose estimation. This exercise also aimed to evaluate the statistical tools used to compare laboratory performance.

Materials and methods

Blood samples were irradiated at three different doses, 1.8, 0.4 and 0 Gy (samples A, C and B) with 4-MV X-rays at 0.5 Gy min⁻¹, and sent to the participant laboratories. Each laboratory was requested to blindly analyze 500 cells per sample and to report the observed frequency of dicentric chromosomes per metaphase and the corresponding estimated dose.

Results

This ILC demonstrates that blood samples can be successfully distributed among laboratories worldwide to perform biological dosimetry in case of a mass casualty event. Having achieved a substantial harmonization in multiple areas among the RENEB laboratories issues were identified with the available statistical tools, which are not capable to advantageously exploit the richness of results of a large ILCs. Even though Z- and U-tests are accepted methods for biodosimetry ILCs, setting the number of analyzed metaphases to 500 and establishing a tests’ common threshold for all studied doses is inappropriate for evaluating laboratory performance. Another problem highlighted by this ILC is the issue of the dose-effect curve diversity. It clearly appears that, despite the initial advantage of including the scoring specificities of each laboratory, the lack of defined criteria for assessing the robustness of each laboratory’s curve is a disadvantage for the ‘one curve per laboratory’ model.

Conclusions

Based on our study, it seems relevant to develop tools better adapted to the collection and processing of results produced by the participant laboratories. We are confident that, after an initial harmonization phase reached by the RENEB laboratories, a new step toward a better optimization of the laboratory networks in biological dosimetry and associated ILC is on the way.

中文翻译：

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2017 年 RENEB 实验室间比较：ILC 的局限性和陷阱

 抽象的

 目的

如果发生大规模伤亡放射事件，则需要联网来克服激增限制并在生物剂量测定实验室之间快速获得均质结果（报告的畸变频率或估计剂量）。这些结果在此类网络内必须一致。实验室间比较（ILC）被广泛接受以实现这种同质性。在欧洲层面，人们为协调生物剂量测定实验室做出了巨大努力，特别是在 MULTIBIODOSE 和 RENEB 项目期间。为了继续协调工作，RENEB 联盟发起了比 RENEB 网络更大的比对，因为它涉及来自 21 个国家的 38 个实验室。在该 ILC 中，从血液运输到剂量估计，整个过程的所有步骤都受到监控。这项练习还旨在评估用于比较实验室性能的统计工具。

 材料和方法

用0.5 Gy min ^-1的4-MV X射线以三种不同剂量1.8、0.4和0 Gy（样品A、C和B）照射血样，并将其发送至参与实验室。每个实验室被要求对每个样本 500 个细胞进行盲法分析，并报告每个中期双着丝粒染色体的观察频率和相应的估计剂量。

 结果

该 ILC 证明，在发生大规模伤亡事件时，血液样本可以成功地在世界各地的实验室之间分配，以进行生物剂量测定。 RENEB 实验室在多个领域实现了实质性协调后，利用现有的统计工具发现了问题，这些工具无法有利地利用大型 ILC 的丰富结果。尽管Z和U测试是生物剂量测定 ILC 公认的方法，但将分析中期的数量设置为 500 并为所有研究剂量建立测试的通用阈值对于评估实验室性能是不合适的。该ILC强调的另一个问题是剂量效应曲线多样性问题。显然，尽管包含每个实验室的评分特异性具有最初的优势，但缺乏评估每个实验室曲线稳健性的明确标准是“每个实验室一条曲线”模型的缺点。

 结论

根据我们的研究，开发更好地适应参与实验室产生的结果的收集和处理的工具似乎是相关的。我们相信，在 RENEB 实验室达到初步协调阶段后，生物剂量测定和相关 ILC 实验室网络的更好优化即将迈出新的一步。