Lessons from past radiation accidents: Critical review of methods addressed to individual dose assessment of potentially exposed people and integration with medical assessment.

The experiences of the Chernobyl and Fukushima nuclear accidents showed that dosimetry was the essential tool in the emergency situation for decision making processes, such as evacuation and application of protective measures. However, at the consequent post-accidental phases, it was crucial also for medical health surveillance and in further adaptation to changed conditions with regards to radiation protection of the affected populations. This review provides an analysis of the experiences related to the role of dosimetry (dose measurements, assessment and reconstruction) regarding health preventive measures in the post-accidental periods on the examples of the major past nuclear accidents such as Chernobyl and Fukushima. Recommendations derived from the review are called to improve individual dose assessment in case of a radiological accident/incident and should be considered in advance as guidelines to follow for having better information. They are given as conclusions.

Uncertainty of fast biological radiation dose assessment for emergency response scenarios.

PURPOSE: Reliable dose estimation is an important factor in appropriate dosimetric triage categorization of exposed individuals to support radiation emergency response. MATERIALS AND METHODS: Following work done under the EU FP7 MULTIBIODOSE and RENEB projects, formal methods for defining uncertainties on biological dose estimates are compared using simulated and real data from recent exercises. RESULTS: The results demonstrate that a Bayesian method of uncertainty assessment is the most appropriate, even in the absence of detailed prior information. The relative accuracy and relevance of techniques for calculating uncertainty and combining assay results to produce single dose and uncertainty estimates is further discussed. CONCLUSIONS: Finally, it is demonstrated that whatever uncertainty estimation method is employed, ignoring the uncertainty on fast dose assessments can have an important impact on rapid biodosimetric categorization.

RENEB - Running the European Network of biological dosimetry and physical retrospective dosimetry.

PURPOSE: A European network was initiated in 2012 by 23 partners from 16 European countries with the aim to significantly increase individualized dose reconstruction in case of large-scale radiological emergency scenarios. RESULTS: The network was built on three complementary pillars: (1) an operational basis with seven biological and physical dosimetric assays in ready-to-use mode, (2) a basis for education, training and quality assurance, and (3) a basis for further network development regarding new techniques and members. Techniques for individual dose estimation based on biological samples and/or inert personalized devices as mobile phones or smart phones were optimized to support rapid categorization of many potential victims according to the received dose to the blood or personal devices. Communication and cross-border collaboration were also standardized. To assure long-term sustainability of the network, cooperation with national and international emergency preparedness organizations was initiated and links to radiation protection and research platforms have been developed. A legal framework, based on a Memorandum of Understanding, was established and signed by 27 organizations by the end of 2015. CONCLUSIONS: RENEB is a European Network of biological and physical-retrospective dosimetry, with the capacity and capability to perform large-scale rapid individualized dose estimation. Specialized to handle large numbers of samples, RENEB is able to contribute to radiological emergency preparedness and wider large-scale research projects.

Operational guidance for radiation emergency response organisations in Europe for using biodosimetric tools developed in EU MULTIBIODOSE project.

In the event of a large-scale radiological emergency, the triage of individuals according to their degree of exposure forms an important initial step of the accident management. Although clinical signs and symptoms of a serious exposure may be used for radiological triage, they are not necessarily radiation specific and can lead to a false diagnosis. Biodosimetry is a method based on the analysis of radiation-induced changes in cells of the human body or in portable electronic devices and enables the unequivocal identification of exposed people who should receive medical treatment. The MULTIBIODOSE (MBD) consortium developed and validated several biodosimetric assays and adapted and tested them as tools for biological dose assessment in a mass-casualty event. Different biodosimetric assays were validated against the 'gold standard' of biological dosimetry-the dicentric assay. The assays were harmonised in such a way that, in an emergency situation, they can be run in parallel in a network of European laboratories. The aim of this guidance is to give a concise overview of the developed biodosimetric tools as well as how and when they can be used in an emergency situation.

Inter- and intra-laboratory comparison of a multibiodosimetric approach to triage in a simulated, large scale radiation emergency.

PURPOSE: The European Union's Seventh Framework Programme-funded project 'Multi-disciplinary biodosimetric tools to manage high scale radiological casualties' (MULTIBIODOSE) has developed a multiparametric approach to radiation biodosimetry, with a particular emphasis on triage of large numbers of potentially exposed individuals following accidental exposures. In November 2012, an emergency exercise took place which tested the capabilities of the MULTIBIODOSE project partners. The exercise described here had a dual purpose: Intercomparison of (i) three biodosimetric assays, and (ii) the capabilities of the seven laboratories, with regards to provision of triage status for suspected radiation exposed individuals. MATERIALS AND METHODS: Three biological dosimetry tools - the dicentric, micronucleus and gamma-H2AX (the phosphorylated form of member X of histone H2A, in response to DNA double-strand breaks) foci assays - were tested, in addition to provision of the triage status results (low exposure: < 1 Gy; medium exposure: 1-2 Gy; high exposure: > 2 Gy) by the MULTIBIODOSE software. The exercise was run in two modes: An initial triage categorisation of samples (based on the first dose estimates for each assay received from each laboratory) followed by collation of the full set of estimated doses (all the results from all modes of each assay carried out by the participating laboratories) calculated using as many modes of operation as possible of the different assays developed during the project. Simulated acute whole body and partial body exposures were included. RESULTS: The results of the initial triage categorisation and the full comparison of assays and methods within and between laboratories are presented here. CONCLUSIONS: The data demonstrate that the MULTIBIODOSE approach of applying multiparametric tools to radiation emergencies is valid and effective.

Induction and repair of DNA strand breaks and oxidised bases in somatic and spermatogenic cells from the earthworm Eisenia fetida after exposure to ionising radiation.

Methods for analysing oxidised DNA lesions [formamidopyrimidine glycosylase (Fpg)-sensitive sites] in coelomocytes and spermatogenic cells from the earthworm Eisenia fetida using the Fpg-modified comet assay were established. The DNA integrity (SSBs = strand breaks plus alkali labile sites and Fpg-sensitive sites) in cells from E. fetida continuously exposed to (60)Co gamma-radiation (dose rates 0.18-43 mGy/h) during two subsequent generations (F0 and F1) were measured and related to effects on reproduction end points which have already been reported. The data suggest a slight increase of Fpg-sensitive sites in spermatogenic cells from worms exposed at 11 mGy/h in the F0 generation but not in F1, whereas reduced reproduction had been observed at dose rates at or >4 mGy/h in F0 and at 11 mGy/h in F1. Using acute X-rays (41.9 Gy/h), dose-response relationships were established for SSBs in coelomocytes and spermatogenic cells exposed in vitro. In vivo DNA repair was studied by measuring the decrease in damage (SSBs and Fpg-sensitive sites) in coelomocytes and spermatogenic cells isolated from worms at different times (0-6 h) after acute X-ray exposure (4 Gy). SSBs were repaired in coelomocytes following biphasic kinetics, i.e. with a fast and a slow half-life (t(1/2)) of 36 min (95%) and 6.7 h (5%), respectively. Fpg-sensitive sites were repaired at considerably lower rates (t(1/2) = 4-5 h). In spermatogenic cells, SSB repair during the first hour was observed but a half-life could not be estimated. Repair of Fpg-sensitive sites could not be determined. In general, a reduced repair of Fpg-sensitive sites suggests a higher potential for accumulation of oxidised lesions, compared to SSBs, in earthworms exposed to radiation and other environmental contaminants. This is the first study comparing DNA damage with reproduction in earthworms exposed to ionising radiation.

Recommendations from the International Union of Radioecology to improve guidance on radiation protection.

This brief commentary summarizes the views of a working group assembled by the International Union of Radioecology to advance the approaches used to evaluate effects of radioactive materials in the environment. The key message in both the research needs and the recommendations for management of radioactive materials centers around the need to adopt an ecocentric approach that recognizes the interconnectedness of biota, including humans, and ecological processes.

A new handbook on triage, monitoring and treatment of people following malevolent use of radiation.

Through the Euratom 6 Framework Programme, the European Commission is co-sponsoring the specific targeted research project "Triage, Monitoring and Treatment-Handbook for management of the public in the event of malevolent use of radiation" (TMT Handbook). The main aim of the project is to produce a handbook for the effective and timely triage, monitoring, and treatment of people exposed to radiation following a malevolent act. The World Health Organization contributed to this project with development of guidelines on medical and public health response. A training course based on the TMT Handbook was developed. It will help to enhance national capacity for planning and response to acts involving the malevolent use of radiation. The course will also provide a platform to identify common challenges and discuss opportunities for harmonizing response strategies throughout the European Union. Focusing on its medical and public health response aspects, this paper introduces the TMT Handbook and its potential applicability not only as practical guidance for end-users but also as a useful tool for education and training.

Types of radiation mass casualties and their management.

Management of radiation mass casualty exposure that may occur as a result of nuclear or radiation accident will depend on the type of accident, and of the knowledge about the actual radiation exposure situation for those who might be involved. Management of the public after an accident in a nuclear or radiation installation will follow existing specific emergency plans, and will take advantage of existing radiation monitoring systems. In other radiation mass casualty exposures, whenever accidental or malevolent use of radiation, there will be a requirement to employ screening programs for indentifying and sorting out exposed people (radiological triage), who will need medical treatment and/or other assistance like decontamination and individual dose assessment. In the later stage after the accident the monitoring for dose assessment purposes for those who will need medical or public health assistance will be required. Demand for dose assessment for large groups of individuals may create the need for international assistance. Prompt and credible public information is vital in all radiation emergencies, and it would be even more important in situations when radiation mass casualties result from exposures to nuclear or radiological material out of regulatory control. In such situations unpredictability of the event creates increase in the risk perception and public communication activities of the authorities will be the key element to prevent unnecessary fear and panic, and the measure to reassure the populace.

[Iodine prophylaxis following nuclear accidents]. / Jodprofylakse ved strålingsulykker.

Radioactive iodine isotopes may be released to air to a varying degree during accidents with nuclear reactors. Iodine tablets, taken before or shortly after such release, protect against intake of radioactive iodine isotopes, but not against other radionuclides. Iodine prophylaxis can be a relevant countermeasure in Norway and will be implemented according to recommendations from the Crisis Committee for Nuclear and Radiological Emergencies. The Chernobyl accident confirmed that the risk for radiogenic thyroid cancer is much higher for foetuses and children and adolescents under 18 years. An epidemiological study showed that intake of iodine tablets could reduce the risk for thyroid cancer by a factor of three. For children, the WHO has therefore recommended a 10 mGy avertable dose to the thyroid. The Norwegian Radiation Protection Authority acknowledge the WHO guidelines and advise that the first priority of all emergency preparedness planning for potential releases that can cause dispersion of radioactive iodine, should be given to the protection of pregnant and breast-feeding women, newborns and children under 18 years. Iodine tablets should be taken immediately (preferably not later than a few hours) in situations where inhalation of radioactive iodine may occur. It should be underlined that iodine prophylaxis is one of several emergency countermeasures; other measures are sheltering and evacuation. The latter two countermeasures will protect not only from intake of radioactive iodine, but also against other radionuclides that may be released. Based on the present risk assessment in Norway, iodine tablets have been distributed to the counties north of Salten. In addition, there is an emergency stockpile of iodine tablets in Oslo.