Integration of new biological and physical retrospective dosimetry methods into EU emergency response plans - joint RENEB and EURADOS inter-laboratory comparisons

Purpose: RENEB, ‘Realising the European Network of Biodosimetry and Physical Retrospective Dosimetry,’ is a network for research and emergency response mutual assistance in biodosimetry within the EU. Within this extremely active network, a number of new dosimetry methods have recently been proposed or developed. There is a requirement to test and/or validate these candidate techniques and inter-comparison exercises are a well-established method for such validation. Materials and methods: The authors present details of inter-comparisons of four such new methods: dicentric chromosome analysis including telomere and centromere staining; the gene expression assay carried out in whole blood; Raman spectroscopy on blood lymphocytes, and detection of radiation-induced thermoluminescent signals in glass screens taken from mobile phones. Results: In general the results show good agreement between the laboratories and methods within the expected levels of uncertainty, and thus demonstrate that there is a lot of potential for each of the candidate techniques. Conclusions: Further work is required before the new methods can be included within the suite of reliable dosimetry methods for use by RENEB partners and others in routine and emergency response scenarios.VII Programa Marco de Investigación y Desarrollo (VIIPM) de la Unión Europea. nº 295513European Radiation Dosimetry Group (EURADOS) de la Unión Europea. EURADOS WG1

RENEB accident simulation exercise

Purpose: The RENEB accident exercise was carried out in order to train the RENEB participants in coordinating and managing potentially large data sets that would be generated in case of a major radiological event. Materials and methods: Each participant was offered the possibility to activate the network by sending an alerting email about a simulated radiation emergency. The same participant had to collect, compile and report capacity, triage categorization and exposure scenario results obtained from all other participants. The exercise was performed over 27 weeks and involved the network consisting of 28 institutes: 21 RENEB members, four candidates and three non-RENEB partners. Results: The duration of a single exercise never exceeded 10 days, while the response from the assisting laboratories never came later than within half a day. During each week of the exercise, around 4500 samples were reported by all service laboratories (SL) to be examined and 54 scenarios were coherently estimated by all laboratories (the standard deviation from the mean of all SL answers for a given scenario category and a set of data was not larger than 3 patient codes). Conclusions: Each participant received training in both the role of a reference laboratory (activating the network) and of a service laboratory (responding to an activation request). The procedures in the case of radiological event were successfully established and tested

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

Review of retrospective dosimetry techniques for external ionising radiation exposures

The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on 'Retrospective Dosimetry' has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure. Endpoints and assays include dicentrics, translocations, premature chromosome condensation, micronuclei, somatic mutations, gene expression, electron paramagnetic resonance, thermoluminescence, optically stimulated luminescence, neutron activation, haematology, protein biomarkers and analytical dose reconstruction. Individual characteristics of these techniques, their limitations and potential for further development are reviewed, and their usefulness in specific exposure scenarios is discussed. Whilst no single technique fulfils the criteria of an ideal dosemeter, an integrated approach using multiple techniques tailored to the exposure scenario can cover most requirements. © The Author 2010. Published by Oxford University Press. All rights reserved

Integration of new biological and physical retrospective dosimetry methods into EU emergency response plans : joint RENEB and EURADOS inter-laboratory comparisons

Purpose: RENEB, 'Realising the European Network of Biodosimetry and Physical Retrospective Dosimetry,' is a network for research and emergency response mutual assistance in biodosimetry within the EU. Within this extremely active network, a number of new dosimetry methods have recently been proposed or developed. There is a requirement to test and/or validate these candidate techniques and inter-comparison exercises are a well-established method for such validation. Materials and methods: The authors present details of inter-comparisons of four such new methods: dicentric chromosome analysis including telomere and centromere staining; the gene expression assay carried out in whole blood; Raman spectroscopy on blood lymphocytes, and detection of radiation induced thermoluminescent signals in glass screens taken from mobile phones. Results: In general the results show good agreement between the laboratories and methods within the expected levels of uncertainty, and thus demonstrate that there is a lot of potential for each of the candidate techniques. Conclusions: Further work is required before the new methods can be included within the suite of reliable dosimetry methods for use by RENEB partners and others in routine and emergency response scenarios

Elektronen-Spin-Resonanz-Datierung von Quarz : Grundlagen, Systematik und Anwendungen unter Einbeziehung der Thermolumineszenz

Die Arbeit beschäftigt sich mit der Methodik und Anwendung der Elektronen-Spin-Resonanz-Datierung an Quarzen. Zu den ESR-Pulverspektren wurden Simulationen durchgeführt, die eine weitestgehende Zuordnung der einzelnen Komponenten eines Pulverspektrums zu bestimmten Gitterdefekten ermöglichen. Die Fremdatomzentren Germanium und Titan weisen bei Bestrahlung eine überlagerung von Produktion und Reduktion auf, welche näherungsweise quantitativ beschrieben werden konnte. Die Dosisaufbaukurve des Fremdatomzentrums Aluminium weicht bei hohen Dosen vom Modell eines einfach exponentiell sättigenden Wachstums ab und lässt sich über den untersuchten Dosisbereich durch die Summe von zwei exponentiellen Sättigungsfunktionen beschreiben. Vergleichende ESR- und Thermolumineszenz (TL)-Untersuchungen an Quarzen geben Hinweise darauf, dass das Al-Zentrum das Rekombinationszentrum für die blaue (470-500 nm) Emission in der Lumineszenz sein kann, während die Elektronenfalle kein bekanntes ESR-Zentrum darstellt. Angewandt wurde die ESR-Methode zur Datierung junger Vulkanite aus dem Vulkanfeld der Eifel und des Egergrabens, Tschechei. ESR-Alter an Quarz-Xenolithen der Eifel zeigen eine gute übereinstimmung mit unabhängigen Altern bis 500 ka. Bei einer Lokation des Egergrabens zeigt sich aber, dass die thermische Stabilität des Al-Zentrums signifikant von Probe zu Probe variieren kann. Für zwei Proben wurde eine Altersüberschätzung aufgrund unvollständiger Nullstellung festgestellt, und schwache oder nicht-existente E1'- und OHC-Signale werden als möglicher Nachweis einer vollständigen Nullstellung diskutiert

Quartz thermoluminescence spectra in the high-dose range

The red thermoluminescence (RTL) emission of quartz is associated with advantageous features such as high saturation dose and good reproducibility. Previous studies, however, noted inexplicable RTL glow curve shapes with new peaks at large doses (kGy range). Here we present TL spectra of two granitic quartz samples over the additive gamma-dose range 0.1-47.9 kGy. While for doses between 0.4 and 1 kGy the TL spectra are dominated by the red emission at 1.95 eV (630 nm), a blue emission at 2.67 eV (465 nm) becomes prominent for higher doses. For one sample, this blue component completely dominates the spectrum for doses > 12.2 kGy with intensity maxima around 200 degrees C and > 350 degrees C (heating rate 2 K s(-1)). The other sample still contains well resolvable red and blue emissions at the largest dose with similar TL peak positions. Signal saturation for the blue emission in the glow curve range 260-300 degrees C is not yet reached following an additive gamma-dose of 47.9 kGy, whereas the red emission generally shows a more subdued signal response for doses > 5-12 kGy. These findings agree qualitatively with additional monochromatic blue and red TL measurements on the same samples. The evolution of supplementary radiofluorescence spectra over the entire gamma-dose range is more complex, but suggests that the sensitisation of the blue wavelength region occurs during heating and not during irradiation and through creation of electron traps rather than recombination centres (most likely [AlO4](0) sites). The sharp sensitivity increase at 1 kGy might likewise be related to alkali ion redistribution and/or the removal of non-radiative competitive recombination pathways. While the blue emission still requires thorough investigation, care should be taken when recording RTL using optical filters since significant portions of the registered TL could originate from the blue component entering the RTL transmission window. In practical terms, the dose-dependent change in relative intensities of blue and red TL emissions might help in detecting exposure to high doses

A TL study of protective glasses of mobile phones for retrospective dosimetry

Several studies have shown that certain components of mobile phones, such as electronic components, display or touch screen glass, are suitable as emergency dosimeters in case of radiological incidents. However, so far the methods are frequently destructive and in case of a dose assessment the mobile phone will be destroyed. In order to overcome this problem, alternative materials need to be sought and further research is necessary. Building on results of a previous study, we further investigated protective glasses in this work, which have become an alternative material for dose reconstruction. Protective glasses are easy to sample and cheap, have become very popular to protect the surface of phones, can be easily replaced without complete destruction of an expensive smartphone, thus a dose assessment method based on this material will potentially find much greater public acceptance. The aim of this study was to optimize the detection window by systematically investigating the radiation-induced TL signals and intrinsic zero dose signals. Using two selected detection windows, the long-term and optical stability of the TL signals were investigated. The set of nine different protective glass samples studied fell into two groups with different fading and optical bleaching characteristics. Further research is necessary in order to reduce the zero dose signal, to reinvestigate the dosimetric properties and to verify the final protocol using a realistic irradiation test

Mobile phone screen protector glass: A TL investigation of the intrinsic background signal

International audienceScreen protector glasses are often used to protect the display screen surfaceof mobile phones against physical damage. Their dosimetric properties wererecently studied by thermoluminescence with the aim of using these itemsas potential emergency dosimeters in the event of a radiological accident.They are sensitive to ionizing radiation and they could be easily removed andreplaced without destroying the phone in case of a dose assessment. However,an intrinsic background signal that partially overlaps with the radiation-inducedTL signal is observed. The reconstructed dose could be overestimated ifnot properly taken into account. The homogeneity of this confoundingsignal on the surface of several screen protectors was estimated and achemical treatment with hydrofluoric acid (HF 40%) was tested to minimizeits contribution. For most of the samples studied, the intrinsic backgroundsignal remained a serious issue for dose reconstruction. Additionally, the TLsignals were measured in the red detector range using two different modelsof red-sensitive photomultiplier tubes. The homogeneity of the intrinsicbackground signal on the surface of screen protectors was examined andthe results of the reduction of this signal by the chemical HF treatmentwere discussed