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Purpose Based on the experience of biodosimetry laboratories during the COVID-19 pandemic, the purpose of this paper is to describe the challenges of providing biodosimetry service in the event of a major radiation incident during a pandemic. This includes describing some of the preparations and planning made by biodosimetry laboratories and special challenges in maintaining a state of readiness while adhering to safety protocols and balancing the need to assist with the COVID-19 response where possible. Experiences of several biodosimetry laboratories will be described and lessons learned will be outlined that could be applied to any large population-scale emergencies. Conclusions There are many challenges that arise when maintaining capacity and capabilities for biodosimetry when faced with a global pandemic such as COVID-19. The key is to be prepared for anything within reason. This includes, but is not limited to, maintaining flexibility, shifting and reorganizing deployment of staff between pandemic response and biodosimetry needs, strengthening networks to be able to provide assistance to other laboratories, managing staff in the face of possible infections and preparing protocols for the handling of potentially infected biological samples according to regulatory requirements. By implementing these recommendations, international biodosimetry networks can be prepared to address large-scale radiological incidents within the context of a pandemic and ensure the safety of biodosimetry personnel as well as victims in such dual emergencies.

In the event of a criticality accident, not only the maximal doses received by the victims must be determined but it is also crucial to evaluate the doses to the different organs. With a neutron component, morphology is a key parameter in the organ dose calculation. As the simulation tools can be time consuming to proceed, especially if morphology is taken into account, for all the victims, it may be very useful to have a database of conversion coefficients that allow to obtain the organ doses from the dose measured in the dosemeter for different kinds of morphology. In this paper, we present a study performed to evaluate such conversion coefficients using voxelized anthropomorphic phantoms. These coefficients take into account two crucial parameters having an impact on the dose at the organs: the orientation of the victim in the radiation field and the morphology, that is to say the body mass index of the different victims.

After the Fukushima accident, initiatives emerged offering the public the possibility to realise measurements of the radioactivity in the environment with various devices and to share data and experiences through collaborative tools. The objective of the OpenRadiation project is to offer the public the opportunity to perform measurements of the radioactivity using connected dosimeters on smartphones. The challenge is to operate such a system on a sustainable basis in normal situations and in order to be useful in an emergency situation. In normal situations, this project is based on a collaborative approach including pedagogical activities. In case of emergency situation, data from the field will be available in “real time” providing an opportunity for the emergency management and the communication with the public. The practical objectives are to develop i) a website centralising measurements using various dosimeters, providing dose rate maps with raw and filtered data and offering dedicated areas for specific projects and exchanges about data and ii) a dosimetric app using a connected dosimeter. This project is conducted within a partnership between organisms’ representative of the scientific community and associations to create links with the public.

International audience; With a typical production altitude of ∼12 km, Terrestrial Gamma ray Flash (TGF) sources are close to commercial flight altitudes, and these events could potentially be an unforeseen exposure to ionizing radiation for aircraft passengers and crews. wyer et al. (2010) estimated the dose that a TGF could produce, andD showed that TGFs in principle could be an additional non‐negligible factor to the exposure for aircraft passengers. The regulations for aircrew protection against radiation, only consider the radiation of galactic and solar origin (ICRP, 2007; Bottollier‐Depois et al., 2012). Other possible sources of exposure, such as TGFs, are not yet considered, mainly because of the lack of reliable data on possible dose level and on the probability for an airplane to be in the vicinity of such an event. In order to improve the evaluation of the TGF exposure level and associated risks, and as there is still a divergence of opinion about the exact source mechanisms, we present calculations of doses produced by high‐energy electrons in TGF sources, within two different lightning leader‐based production models: (1) a pure lightning leader model and (2) considering further avalanches in a homogeneous electric field region. We find that although the doses from photon and secondary electron beams are weak, the dose potentially received by passengers inside the TGF electron source regions may be very high ( > 20 mSv). The results reported in the present paper call for a need to perform a thorough risk assessment including the probability for an aircraft to be in a TGF source region.

Purpose: Depending on the exposure scenario, different biological and/or physical assays will be required to recover the exposure situation and to obtain reliable dose estimates to aid medical decision making. Inter-laboratory comparisons (ILCs) are a central tool to validate and improve the performance of methods and laboratories. In most cases such ILCs are performed under laboratory conditions where the influence of parameters contributing to uncertainties can be minimized. In a reallife scenario, the situation is much more complicated, and it is therefore crucial to validate methods and laboratories’ abilities to carry out these methods under more realistic conditions. In 2019, EURADOS (The European Radiation Dosimetry Group) Working Group 10 (Retrospective Dosimetry) and RENEB (Running the European Network of Biological and retrospective Physical dosimetry) organized a field exercise in Lund, Sweden, to validate different methods for biological and physical retrospective dosimetry in parallel by simulating real- life exposure scenarios. Materials and methods: For the dicentric chromosome assay (DCA), 18 blood tubes were distributed across 8 thermos flasks filled with heated water and positioned at the hips and shoulders of anthropomorphic phantoms in different geometries. Two irradiations were performed with a 1.36 TBq 192Ir-source, each with two phantoms, to simulate close, distant, lateral or partially shielded exposures. For each of the blood tubes DCA dose estimates were provided by at least one laboratory and for tubes from four thermos flasks by 17 participating RENEB laboratories. In addition, blood from the different thermos flasks on each phantom was mixed to simulate heterogeneous exposures. Three radio-photoluminescence (RPL) glass dosimeters (GD) were placed at each tube to assess reference doses and the inter- and intra-tube variability. Results: The results from the DCA were homogeneous between participants and matched well with RPL GD reference doses (≥95% of estimates within ±0.5 Gy of the reference). For samples close to the source, exposed to doses >1 Gy, systematic underestimation could be corrected by accounting for exposure time. Heterogeneity within and between tubes was detected for RPL GD reference doses as well as for doses estimates from the DCA. The sample simulating a heterogeneous exposure with two different doses was detected by ~50% of the participants. Conclusions: The participants were able to successfully estimate the doses and to provide important information on the exposure scenarios under conditions closely resembling a real-life situation. The reliability of the results emphasizes the value of the DCA for retrospective dosimetry under field conditions.

The Orsay Proton therapy Center (ICPO) has a long history of intracranial radiotherapy using both double scattering (DS) and pencil beam scanning (PBS) techniques, and is actively investigating a promising modality of spatially fractionated radiotherapy using proton minibeams (pMBRT). This work provides a comprehensive comparison of the organ-specific secondary neutron dose due to each of these treatment modalities, assessed using Monte Carlo (MC) algorithms and measurements. A MC model of a universal nozzle was benchmarked by comparing the neutron ambient dose equivalent, H*(10), in the gantry room with measurements obtained using a WENDI-II counter. The secondary neutron dose was evaluated for clinically relevant intracranial treatments of patients of different ages, in which secondary neutron doses were scored in anthropomorphic phantoms merged with the patients’ images. The MC calculated H*(10) values showed a reasonable agreement with the measurements and followed the expected tendency, in which PBS yields the lowest dose, followed by pMBRT and DS. Our results for intracranial treatments show that pMBRT yielded a higher secondary neutron dose for organs closer to the target volume, while organs situated furthest from the target volume received a greater quantity of neutrons from the passive scattering beam line. To the best of our knowledge, this is the first study to compare MC secondary neutron dose estimates in clinical treatments between these various proton therapy modalities and to realistically quantify the secondary neutron dose contribution of clinical pMBRT treatments. The method established in this study will enable epidemiological studies of the long-term effects of intracranial treatments at ICPO, notably radiation-induced second malignancies.

International audience; Scintillators are used in various fields of Earth and atmospheric sciences in order to study high-energy phenomena occurring from ground to the Earth radiation belts. In this chapter, we explore the different scientific domains where high-energy detection is unavoidable, from the study of Earth radioactivity or human nuclear activities to the measure of the particle environment around our planet, including the recent topics on atmospheric gamma-ray processes during thunderstorms.

Large-scale radiation emergency scenarios involving protracted low dose rate radiation exposure (e.g. a hidden radioactive source in a train) necessitate the development of high throughput methods for providing rapid individual dose estimates. During the RENEB (Running the European Network of Biodosimetry) 2019 exercise, four EDTA-blood samples were exposed to an Iridium-192 source (1.36 TBq, Tech-Ops 880 Sentinal) at varying distances and geometries. This resulted in protracted doses ranging between 0.2 and 2.4 Gy using dose rates of 1.5–40 mGy/min and exposure times of 1 or 2.5 h. Blood samples were exposed in thermo bottles that maintained temperatures between 39 and 27.7 °C. After exposure, EDTA-blood samples were transferred into PAXGene tubes to preserve RNA. RNA was isolated in one laboratory and aliquots of four blinded RNA were sent to another five teams for dose estimation based on gene expression changes. Using an X-ray machine, samples for two calibration curves (first: constant dose rate of 8.3 mGy/min and 0.5–8 h varying exposure times; second: varying dose rates of 0.5–8.3 mGy/min and 4 h exposure time) were generated for distribution. Assays were run in each laboratory according to locally established protocols using either a microarray platform (one team) or quantitative real-time PCR (qRT-PCR, five teams). The qRT-PCR measurements were highly reproducible with coefficient of variation below 15% in ≥ 75% of measurements resulting in reported dose estimates ranging between 0 and 0.5 Gy in all samples and in all laboratories. Up to twofold reductions in RNA copy numbers per degree Celsius relative to 37 °C were observed. However, when irradiating independent samples equivalent to the blinded samples but increasing the combined exposure and incubation time to 4 h at 37 °C, expected gene expression changes corresponding to the absorbed doses were observed. Clearly, time and an optimal temperature of 37 °C must be allowed for the biological response to manifest as gene expression changes prior to running the gene expression assay. In conclusion, dose reconstructions based on gene expression measurements are highly reproducible across different techniques, protocols and laboratories. Even a radiation dose of 0.25 Gy protracted over 4 h (1 mGy/min) can be identified. These results demonstrate the importance of the incubation conditions and time span between radiation exposure and measurements of gene expression changes when using this method in a field exercise or real emergency situation.

International audience; La décision d’irradiation en cours de grossesse repose sur un compromis bénéfice risque de deux ordres :le risque maternel et le risque fœtal. L’objectif de ce travail concernait le risque fœtal et la procédure demesure de dose à l’utérus en protonthérapie par faisceau pulsé. L’exposition fœtale au cours du traite-ment est liée à deux sources : la phase de traitement, et la phase de repositionnement. Sur un fantômeanthropomorphe de type Alderson-Rando (170 cm, 74 kg) en position de traitement, un détecteur detype « Compteur Proportionnel Equivalent-Tissu » (CPET), adapté à l’analyse des champs de rayonne-ments complexes (neutroniques et photoniques) a été utilisé pour la phase de traitement. Un radiamètrede type AT1123 a été utilisé pour la mesure des photons engendrés par les rayonnements X. Une dosimé-trie in vivo a été proposée via des dosimètres radio-photo-luminescents placés à la thyroïde en utilisantun facteur de proportionnalité permettant une vérification de la dose fœtale de manière quotidienne. Laphase de traitement engendre des doses à l’utérus plus élevées que pour la phase de positionnement,néanmoins celles-ci restent très faibles. La dose équivalente au niveau de l’utérus pour l’ensemble dutraitement est de 840 Sv. Il a pu être mis au point une méthodologie de mesure de la dose hors champen faisceau pulsé de protonthérapie ORL. La dose fœtale au premier trimestre était bien inférieure aux100 mGy déterminés par la Commission Internationale de Protection Radiologique

Recent advances in laser driven accelerators boosted the development of high dose-rate fast pulsed systems all over the world. The stray radiation comprises primarily high-energy photons, resulting in extremely high dose rates within pico-/femto-second pulses. Dose measurements in such conditions have to be evaluated to validate methods. To tackle this challenge the EUropean RAdiation DOSimetry Group (EURADOS) started a program of dosimeters intercomparison, with a progressive approach, starting by a first evaluation in fields with μs pulse duration. The first comparison took place at the Lausanne University Hospital Center with an electron LINAC in Sept. 2017 involving 7 European institutes. Several passive and active dosimeters were tested with a tunable air kerma per pulse of the order of MGy/h. All instruments, except electrets, did not show any dose rate dependence, thus being selected as possible candidates for further studies.

International audience; EPR spectra of alanine dosimeters irradiated by gamma-rays and by alpha-particles were measured at different microwave power. The spectra were decomposed into three components corresponding to different stable radiation-induced radicals. Different ratio of the components was obtained for gamma- and alpha-irradiated alanine. The observed effect can be used for discrimination of the contribution of alpha- and gamma-radiationin mixed radiation field. That may be useful for control of dose at phantom experiments with neutron boron capture therapy, performed in mixed neutron-gamma field in which alpha-particles are emitted through neutrons capture reaction with boron.

International audience; Results of a comprehensive study of the TLD-700H/600H (Harshaw 8840/8841) dosimetry system performance for an extended issue period are presented and discussed. The results provide a technical justification to use the current dosimetry system issues periods up to almost 600 days, far beyond the current 95-day issue period used at the Naval Dosimetry Center (NDC). Extending (or reducing) the issue period has a statistically significant effect on the uncertainty of the dose equivalent values measured within the dosimetry system. In order to accommodate the use of various issue periods for the dosimetry system, the lower limit of detection (LLD) linear model is proposed. A possible limitation of this model (dose fading) is discussed. The factors responsible for both time independent and dependent LLD components are identified. The thermoluminescent residual signal and dosimetry system calibration are responsible for the time-independent LLD component; whereas the factors for time-dependent LLD component are dose fading, radiation background and its standard deviation. Simple formulae for photon and neutron LLDs at variable dosimeter issue periods are proposed. As a result of the experimental study conducted, multiple LLD components were numerically evaluated for the four-element TLD-700H/600H dosimetry system at different issue periods. Implementation of these formulae in the Dose Program may provide a more accurate LLD estimation for each reported dose equivalent at any technically justified dosimeter issue period. © 2017

Accidental exposures to ionising radiations are nowadays managed with assistance from biological and physical retrospective dosimetry which are able to provide individual estimates of dose absorbed by victims. The aim of this work is to describe the development of biodosimetry analysis software within the "EURADOS Working Group 10—Retrospective dosimetry" Task group 10.6. Methods The software has been developed in Python code language that is easy to learn, read, use and extensible (it is possible to add new modules). It can implement C/C++/Fortran, Java functions. It is embeddable in applications and is open source. It is extremely portable to Unix/Linux, Windows, Mac operating systems. The memory management is automatic. The software uses many free scientific python packages (such as numpy, scipy and sympy) and has a user-friendly graphical user interface. Results The software developed was named "Dose REconstruction by Analytical and Monte carlo methods" (D.RE.A.M.) and enables performance of uncertainties analyses though various mathematical methods. In particular, it facilitates: Analytical calculation of combined standard uncertainties Monte Carlo estimation of combined uncertainties Dose reconstruction from least square calibration curves by 1) analytical inversion of the calibration curve function 2) Monte Carlo calculation Dose reconstruction with using Bayesian Method (Markov Chain Monte Carlo Method). This last analysis is still under validation process. After complete validation process this software will be freely available for everybody and will guide the user to the requested results.

ntroduction L-a-alanine has aroused considerable interest for use in radiation ESR dosimetry. In this work, we examined the energy response of alanine ESR films in the low energy X-photon energy range between 1 keV and 40 keV. Dose measurements through a reference ionization chamber and a semiconductor detection system were also performed to complement ESR measurements. Methods Commercial alanine ESR films were used. All ESR signal measurements were also done using an XBand (9.7 GHz) Bruker spectrometer. The dosimeters were irradiated at the "Livio Scarsi" Laboratory (LAX) of the University of Palermo, where X-ray beams in the 1–40 keV energy range are produced using a Seifert SN60 tube. Reference dosimetry measurements were made using a plane parallel chamber with thin polyethylene membranes. X-ray fluxes and energy spectra were measured with an innovative system based on semiconductor detectors (CdTe, Si) and digital pulse processing (DPP) electronics. Results The response of alanine to low-energy X-rays was characterized experimentally. The response as function of dose, the dependence of the ESR signal on the photon energy as well as the stability of the signal with time were investigated. Comparison of the ESR response to high energy photons was also carried out. The relative effectiveness is lower if compared to high-energy photons. Conclusion Alanine dosimeters show very interesting dosimetric features also for these low-energy X-ray beams. To our knowledge, these data have not been previously reported and they may be extremely relevant, e.g., when mapping the high-gradient treatment fields used in microbeam radiation therapy (MRT) with synchrotron radiation.

Today the armed forces and law enforcement personnel wear body armor, helmets, and flak jackets composed substantially of Kevlar® fiber to prevent bodily injury or death resulting from physical, ballistic, stab, and slash attacks. Therefore, there is a high probability that during a radiation accident or its aftermath, the Kevlar®-composed body armor will be irradiated. Preliminary study with samples of Kevlar® foundation fabric obtained from body armor used by the U.S. Marine Corps has shown that all samples evaluated demonstrated an EPR signal, and this signal increased with radiation dose. Based on these results, the authors predict that, with individual calibration, exposure at dose above 1 Gy can be reliably detected in Kevlar® samples obtained from body armor. As a result of these measurements, a post-event reconstruction of exposure dose can be obtained by taking various samples throughout the armor body and helmet worn by the same irradiated individual. The doses can be used to create a whole-body dose map that would be of vital importance in a case of a partial body or heterogeneous exposure.

This article provides an overview of four radiological accidents in Latin America, and includes a history of the events, the clinical manifestations and health consequences for the exposed individuals, the medical response based on preclinical studies and the role of the International Atomic Energy Agency (IAEA) in coordinating medical response assistance.

Radiation measurements 137, 106433 (1-12) (2020). doi:10.1016/j.radmeas.2020.106433, Aircraft crew are one of the groups of radiation workers which receive the highest annual exposure to ionizing radiation. Validation of computer codes used routinely for calculation of the exposure due to cosmic radiation and the observation of nonpredictable changes in the level of the exposure due to solar energetic particles, requires continuous measurements onboard aircraft. Appropriate calibration of suitable instruments is crucial, however, for the very complex atmospheric radiation field there is no single reference field covering all particles and energies involved. Further intercomparisons of measurements of different instruments under real flight conditions are therefore indispensable.In November 2017, the REFLECT (REsearch FLight of EURADOS and CRREAT) was carried out. With a payload comprising more than 20 different instruments, REFLECT represents the largest campaign of this type ever performed. The instruments flown included those already proven for routine dosimetry onboard aircraft such as the Liulin Si-diode spectrometer and tissue equivalent proportional counters, as well as newly developed detectors and instruments with the potential to be used for onboard aircraft measurements in the future. This flight enabled acquisition of dosimetric data under well-defined conditions onboard aircraft and comparison of new instruments with those routinely used.As expected, dosimeters routinely used for onboard aircraft dosimetry and for verification of calculated doses such as a tissue equivalent proportional counter or a silicon detector device like Liulin agreed reasonable with each other as well as with model calculations. Conventional neutron rem counters underestimated neutron ambient dose equivalent, while extended-range neutron rem counters provided results comparable to routinely used instruments. Although the responses of some instruments, not primarily intended for the use in a very complex mixed radiation field such as onboard aircraft, were as somehow expected to be different, the verification of their suitability was one of the objectives of the REFLECT. This campaign comprised a single short flight. For further testing of instruments, additional flights as well as comparison at appropriate reference fields are envisaged. The REFLECT provided valuable experience and feedback for validation of calculated aviation doses., Published by Elsevier Science, Amsterdam [u.a.]

Purpose: The main objective of radiobiology is to establish links between doses and radiation-induced biological effects. In this context, well-defined dosimetry protocols are crucial to the determination of experimental protocols. This work proposes a new dosimetry protocol for cell irradiation in a SARRP and shows the importance of the modification of some parameters defined in dosimetry protocol for physical dose and biological outcomes. Materials and methods: Once all parameters of the configuration were defined, dosimetry measurements with ionization chambers and EBT3 films were performed to evaluate the dose rate and the attenuation due to the cell culture medium. To evaluate the influence of changes in cell culture volume and/or additional filtration, 6-well plates containing EBT3 films with water were used to determine the impact on the physical dose at 80 kV. Then, experiments with the same irradiation conditions were performed by replacing EBT3 films by HUVECs. The biological response was assessed using clonogenic assay. Results: Using a 0.15 mm copper filter lead to a variation of +1% using medium thickness of 0.104 cm to −8% using a medium thickness of 0.936 cm on the physical dose compare to the reference condition (0.313 cm). For the 1 mm aluminum filter, a variation of +8 to −40% for the same medium thickness conditions has been observed. Cells irradiated in the same conditions showed significant differences in survival fraction, corroborating the effects of dosimetric changes on physical dose. Conclusions: This work shows the importance of dosimetry in radiobiology studies and the need of an accurate description of the dosimetry protocol used for irradiation.

Treatment of accidental radiation-induced myelosuppression is primarily based on supportive care and requires specific treatment based on hematopoietic growth factors injection or hematopoietic cell transplantation for the most severe cases. The cytokines used consisted of pegylated erythropoietin (darbepoetin alfa) 500 IU once per week, pegylated G-CSF (pegfilgrastim) 6 mg × 2 once, stem cell factor 20 µg.kg–1 for five days, and romiplostim (TPO analog) 10 µg.kg –1 once per week, with different combinations depending on the accidents. As the stem cell factor did not have regulatory approval for clinical use in France, the French regulatory authorities (ANSM, formerly, AFSSAPS) approved their compassionate use as an investigational drug “on a case-by-case basis”. According to the evolution and clinical characteristics, each patient's treatment was adopted on an individual basis. Daily blood count allows initiating G-CSF and SCF delivery when granulocyte

International audience; This paper compares the performance of four different Tissue-Equivalent proportional counters (TEPC) first in standard radiation fields, with gamma and neutron sources, then in the mixed and complex/intense neutron and photon stray radiation field of a scanning proton therapy facility. The paper focuses on the dead time correction and introduces a new spectra processing methodology to enable the comparison of the four TEPCs while accounting for their different gas filling and gain, lineal energy range of the spectrum and the analysis methodology. Measurements with 137Cs and/or 60Co gamma sources demonstrate variable low-LET threshold for each TEPC while data acquired with a 252Cf neutron source show comparable response of the four TEPCs for high-LET particles. Meanwhile, in the scattered field of proton therapy, microdosimetric spectra measured at different positions and orientations around the patient show a majority of high-LET events at the smallest angle with respect to the beam axis while low-LET particles were mainly dominant at 90° from the beam axis. The introduced processing methodology led to good overlapping of microdosimetric spectra for the four systems. © 2016 Elsevier Ltd

International audience; Biological and physical retrospective dosimetry are recognised as key techniques to provide individual estimates of dose following unplanned exposures to ionising radiation. Whilst there has been a relatively large amount of recent development in the biological and physical procedures, development of statistical analysis techniques has failed to keep pace. The aim of this paper is to review the current state of the art in uncertainty analysis techniques across the 'EURADOS Working Group 10- Retrospective dosimetry' members, to give concrete examples of implementation of the techniques recommended in the international standards, and to further promote the use of Monte Carlo techniques to support characterisation of uncertainties. It is concluded that sufficient techniques are available and in use by most laboratories for acute, whole body exposures to highly penetrating radiation, but further work will be required to ensure that statistical analysis is always wholly sufficient for the more complex exposure scenarios. © Crown copyright 2017.

International audience; 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. © The Author 2014.

In this paper, we report results of radiation dose measurements in fingernails of a worker who sustained a radiation injury to his right thumb while using 130 kVp X-ray for nondestructive testing. Clinically estimated absorbed dose was about 20–25 Gy. Electron paramagnetic resonance (EPR) dose assessment was independently carried out by two laboratories, the Naval Dosimetry Center (NDC) and French Institut de Radioprotection et de Sûreté Nucléaire (IRSN). The laboratories used different equipments and protocols to estimate doses in the same fingernail samples. NDC used an X-band transportable EPR spectrometer, e-scan produced by Bruker BioSpin, and a universal dose calibration curve. In contrast, IRSN used a more sensitive Q-band stationary spectrometer (EMXplus) with a new approach for the dose assessment (dose saturation method), derived by additional dose irradiation to known doses. The protocol used by NDC is significantly faster than that used by IRSN, nondestructive, and could be done in field conditions, but it is probably less accurate and requires more sample for the measurements. The IRSN protocol, on the other hand, potentially is more accurate and requires very small amount of sample but requires more time and labor. In both EPR laboratories, the intense radiation-induced signal was measured in the accidentally irradiated fingernails and the resulting dose assessments were different. The dose on the fingernails from the right thumb was estimated as 14 ± 3 Gy at NDC and as 19 ± 6 Gy at IRSN. Both EPR dose assessments are given in terms of tissue kerma. This paper discusses the experience gained by using EPR for dose assessment in fingernails with a stationary spectrometer versus a portable one, the reasons for the observed discrepancies in dose, and potential advantages and disadvantages of each approach for EPR measurements in fingernails. © 2014, Springer-Verlag Berlin Heidelberg (outside the USA).

High-frequency Q-band (37 GHz) electron paramagnetic resonance (EPR) dosimetry allows to perform fast (i.e., measurement time

Exposure of finger- and toe-nails to ionizing radiation generates an Electron Paramagnetic Resonance (EPR) signal whose intensity is dose dependent and stable at room temperature for several days. The dependency of the radiation-induced signal (RIS) on the received dose may be used as the basis for retrospective dosimetry of an individual's fortuitous exposure to ionizing radiation. Two radiation-induced signals, a quasi-stable (RIS2) and stable signal (RIS5), have been identified in nails irradiated up to a dose of 50 Gy. Using X-band EPR, both RIS signals exhibit a singlet line shape with a line width around 1.0 mT and an apparent g-value of 2.0044. In this work, we seek information on the exact chemical nature of the radiation-induced free radicals underlying the signal. This knowledge may provide insights into the reason for the discrepancy in the stabilities of the two RIS signals and help develop strategies for stabilizing the radicals in nails or devising methods for restoring the radicals after decay. In this work an analysis of high field (94GHz and 240 GHz) EPR spectra of the RIS using quantum chemical calculations, the oxidation-reduction properties and the pH dependence of the signal intensities are used to show that spectroscopic and chemical properties of the RIS are consistent with a semiquinone-type radical underlying the RIS. It has been suggested that semiquinone radicals formed on trace amounts of melanin in nails are the basis for the RIS signals. However, based on the quantum chemical calculations and chemical properties of the RIS, it is likely that the radicals underlying this signal are generated from the radiolysis of L-3,4-dihydroxyphenylalanine (DOPA) amino acids in the keratin proteins. These DOPA amino acids are likely formed from the exogenous oxidation of tyrosine in keratin by the oxygen from the air prior to irradiation. We show that these DOPA amino acids can work as radical traps, capturing the highly reactive and unstable sulfur-based radicals and/or alkyl radicals generated during the radiation event and are converted to the more stable o-semiquinone anion-radicals. From this understanding of the oxidation- reduction properties of the RIS, it may be possible to regenerate the unstable RIS2 following its decay through treatment of nail clippings. However, the treatment used to recover the RIS2 also has the ability to recover an interfering, mechanically-induced signal (MIS) formed when the nail is clipped. Therefore, to use the recovered (regenerated) RIS2 to increase the detection limits and precision of the RIS measurements and, therefore, the dose estimates calculated from the RIS signal amplitudes, will require the application of methods to differentiate the RIS2 from the recovered MIS signal. © The Author 2016.

International audience; After the Fukushima accident, initiatives emerged from the public to carry out themselves measurements of the radioactivity in the environment with various devices, among which smartphones, and to share data and experiences through collaborative tools and social networks. Such measurements have two major interests, on the one hand, to enable each individual of the public to assess his own risk regarding the radioactivity and, on the other hand, to provide “real time” data from the field at various locations, especially in the early phase of an emergency situation, which could be very useful for the emergency management.The objective of the OPENRADIATION project is to offer to the public the opportunity to be an actor for measurements of the radioactivity in the environment using connected dosimetric applications on smartphones. The challenge is to operate such a system on a sustainable basis in peaceful time and be useful in case of emergency. In “peaceful situation”, this project is based on a collaborative approach with the aim to get complementary data to the existing ones, to consolidate the radiation background, to generate alerts in case of problem and to provide education & training and enhanced pedagogical approaches for a clear understanding of measures for the public. In case of emergency situation, data will be available “spontaneously” from the field in “real time” providing an opportunity for the emergency management and the communication with the public. …The practical objective is i) to develop a website centralising data from various systems/dosimeters, providing dose maps with raw and filtered data and creating dedicated areas for specific initiatives and exchanges of data and ii) to develop a data acquisition protocol and a dosimetric application using a connected dosimeter with a bluetooth connection.This project is conducted within a partnership between organisms’ representative of the scientific community and associations to create links with the public.

International audience; Electron paramagnetic resonance (EPR) dosimetry of tooth enamel in X-band has been established as a suitable method for individual reconstruction of doses 0. 1 Gy and higher. The objective was to demonstrate the feasibility of using Q-band EPR in small biopsy tooth enamel samples to provide accurate measurements of radiation doses. Q-band spectra of small (

Ideally, dosimeters should measure the dose without their dosimetric properties being affected by the radiation type being measured. Industry-wide occupational radiation workers that can be potentially exposed to neutron radiation fields are routinely monitored by thermoluminescent (TLD) dosimeters. The neutron dose measured by these devices is obtained from the interaction products of thermal (slow) neutrons and 6 Li. The number of alpha particle and 3 H − ions (tritium) released in the ( n , 6 Li) reaction is proportional to the dose received by the dosimeter. It is a common practice to evaluate the neutron dose indirectly from these products. In this work we present for the first time direct evidence that the neutron exposure to LiF:Mg,Cu,P (TLD-600H) can have deleterious effects on the dosimetric properties of one of the most commonly utilized dosimeters in the world. The interstitial non-negligible tritium dose contribution to the dosimeter is a result of the beta decay of the tritium nuclei interstitially present in the material. If not accounted for the effect of this self irradiation can directly affect the measured occupational dose to workers. In order to estimate the significance of these effects, tritium dose buildup was measured in the TLD-600H irradiated to different neutron doses from a reactor and a 252 Cf source and then calculated in terms of a daily dose buildup rate. The effect of the self irradiation on these dosimeters resulting from tritium decay was extensively studied. The TLD dosimeters that were exposed to neutron doses show a significant dose buildup even after they have been annealed, i.e. even after the signal produced by the incident neutron dose is completely erased from the lower energy trap states of the dosimeter. The other discovered effect of neutron irradiation on TLD-600H is a significant loss in the detection sensitivity (up to 15%).

Results of a feasibility study for the use of the Q-band EPR measurements of fingernails are presented. Details of the first protocol developed for Q-band (34 GHz) EPR dose measurements in fingernails and preliminary results of a dosimetry study in comparison with the commonly-used X-band (9 GHz) are reported. It was found that 1e5 mg sample mass was sufficient for EPR measurements in fingernails in the Q-band, which is significantly less than the 15e30 mg needed for the X-band. This finding makes it possible to obtain sufficient fingernail sample for dose measurements, practically from every finger of any person. Another finding was that the spectral resolution of the mechanically-induced signal (MIS) and radiation-induced signal (RIS) in the Q-band was significantly better than in the X-band. The RIS and MIS in the Q-band spectrum have a more complex structure than in the X-band, which potentially offers the possibility to do dose measurements in fingernails without treatment and immediately after clipping. These findings and recent results related to fingernail dosimetry in the Q-band and its perspectives are discussed here. Published by Elsevier Ltd.

This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Munchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit of which were also calculated by the organizers.

In the event of large-scale radiation accidents and considering a growing terrorism concern, non-invasive and sufficiently accurate retrospective dosimetry methods are necessary to carry out a fast population triage in order to determine which radiation-exposed individuals need medical treatment. Retrospective dosimetry using different electronic components such as resistors, capacitors, and integrated circuits present on mobile phone circuit boards have been considered. Their response has been investigated with luminescence techniques (OSL, IRSL, and TL). The majority of these electronic components exhibit radiation-induced luminescence signals, and the OSL technique seems the most promising for these materials. Results concerning three types of components that present the most interesting OSL characteristics (in terms of signal annealing and sensitivity) and that are the most often present on mobile phone circuit boards are presented. Preheating effects on OSL signal, sensitization, and dose-response curves from 0.7 to 27 Gy for resistors and from 0.7 to 160 Gy for capacitors and integrated circuits, dose recovery tests, and signal stability 10 h after irradiation have been studied and interests and limits of their use evaluated.

A summary of recent developments in fingernail EPR dosimetry is presented in this paper. Until 2007, there had been a very limited number of studies of radiation-induced signals in fingernails. Although these studies showed some promising results, they were not complete with regard to the nature of non-radiation signals and the variability of dose dependence in fingernails. Recent study has shown that the two non-radiation components of the EPR spectrum of fingernails are originated from mechanical stress induced in the samples at their cut. The mechanical properties of fingernails were found to be very similar to those of a sponge; therefore, an effective way to eliminate their mechanical deformation is by soaking them in water. Stress caused by deformation can also significantly modify the dose response and radiation sensitivity. Consequently, it is critically important to take into account the mechanical stress in fingernail samples under EPR dose measurements. Obtained results have allowed formulating a prototype of a protocol for dose measurements in human fingernails.

In the present study, MCNP4B simulation code is used to simulate neutron and photon transport. It gives the conversion coefficients that relate neutron fluence to the dose in tooth enamel (molars and pre-molars only) for 20 energy groups of monoenergetic neutrons with energies from 10-9. to 20 MeV for five different irradiation geometries. The data presented are intended to provide the basis for connection between EPR dose values and standard protection quantities defined in ICRP Publication 74. The results of the calculations for critical organs were found to be consistent with ICRP data, with discrepancies generally less than 10% for the fast neutrons. The absorbed dose in enamel was found to depend strongly on the incident neutron energy for neutrons over 10 keV. The dependence of the data on the irradiation geometry is also shown. Lower bound estimates of enamel radiation sensitivity to neutrons were made using obtained coefficients for the secondary photons. Depending on neutron energy, tooth enamel was shown to register 10-120% of the total neutron dose in the human body in the case of pure neutron exposure and AP irradiation geometry. © 2010 Health Physics Society.

The European Commission has funded within its 6th Framework Programme a three-year project (2005–2007) called CONRAD, COordinated Network for RAdiation Dosimetry. The organizational framework for this project was provided by the European radiation Dosimetry Group EURADOS. Work Package 6 of CONRAD dealt with “complex mixed radiation fields at workplaces” and in this context it organised a benchmark exercise, which included both measurements and calculations, in a stray radiation field at a high-energy particle accelerator at GSI, Germany. The aim was to intercompare the response of several types of active detectors and passive dosemeters in a well-characterised workplace field. The Monte Carlo simulations of the radiation field and the experimental determination of the neutron spectra with various Bonner Sphere Spectrometers are discussed in Rollet et al. (2008) and in Wiegel et al. (2008). This paper focuses on the intercomparison of the response of the dosemeters in terms of ambient dose equivalent. The paper describes in detail the detectors employed in the experiment, followed by a discussion of the results. A comparison is also made with the H*(10) values predicted by the Monte Carlo simulations and those measured by the BSS systems.

The results of electron paramagnetic resonance (EPR) measurements in irradiated fingernails are presented. In total, 83 samples of different fingernails were studied. Five different groups of samples were selected based on the collection time of fingernail samples, their level of mechanical stress, and the number and size of clippings: (1) recently (24 h) cut, stored at room temperature, additionally cut into small pieces immediately prior to study, irradiated and measured with EPR without any treatment of samples, and with rigorous control of size and number of clippings (stressed-old, controlled); (4) previously (>24 h) cut, stored at room temperature, additionally cut into small pieces immediately prior to the study, irradiated and measured with EPR after application of a special treatment to reduce mechanical stress caused by cut, and with rigorous control of size and number of clippings (unstressed-old, controlled); and (5) recently (

The most significant problem of electron paramagnetic resonance (EPR) fingernail dosimetry is the presence of two signals of non-radiation origin that overlap the radiation-induced signal (RIS), making it almost impossible to perform dose measurements below 5 Gy. Historically, these two non-radiation components were named mechanically induced signal (MIS) and background signal (BKS). In order to investigate them in detail, three different methods of MIS and BKS mutual isolation have been developed and implemented. After applying these methods, it is shown here that fingernail tissue, after cut, can be modeled as a deformed sponge, where the MIS and BKS are associated with the stress from elastic and plastic deformations, respectively. A sponge has a unique mechanism of mechanical stress absorption, which is necessary for fingernails in order to perform its everyday function of protecting the fingertips from hits and trauma. Like a sponge, fingernails are also known to be an effective water absorber. When a sponge is saturated with water, it tends to restore to its original shape, and when it loses water, it becomes deformed again. The same happens to fingernail tissue. It is proposed that the MIS and BKS signals of mechanical origin be named MIS1 and MIS2 for MISs 1 and 2, respectively. Our suggested interpretation of the mechanical deformation in fingernails gives also a way to distinguish between the MIS and RIS. The results obtained show that the MIS in irradiated fingernails can be almost completely eliminated without a significant change to the RIS by soaking the sample for 10 min in water. The proposed method to measure porosity (the fraction of void space in spongy material) of the fingernails gave values of 0.46-0.48 for three of the studied samples. Existing results of fingernail dosimetry have been obtained on mechanically stressed samples and are not related to the "real" in vivo dosimetric properties of fingernails. A preliminary study of these properties of pre-soaked (unstressed) fingernails has demonstrated their significant difference from fingernails stressed by cut. They show a higher stability signal, a less intensive non-radiation component, and a nonlinear dose dependence. The findings in this study set the stage for understanding fingernail EPR dosimetry and doing in vivo measurements in the future. © 2008 Springer-Verlag.

This paper presents a measurement campaign carried out in six medical electron linear accelerator facilities to evaluate occupational exposure associated with photons and secondary neutrons for several encountered configurations. No strong correlation between dose and configuration has been observed. Assuming realistic hypotheses, the annual effective dose to staff due to external exposure has been estimated to 0.9 mSv, 54% associated with the decay of activation products and 7% due to exposure to leakage neutrons. © 2008 Elsevier Ltd. All rights reserved.

Some radiation accidents can be accompanied by high local clinically important absorbed doses. In such cases, local doses can be estimated by measuring by electron paramagnetic resonance (EPR) spectrometry radio-induced radicals in bone tissues of radiation victims. To get a precise and a reliable assessment of absorbed dose by EPR on human bone tissue, a lot of additional information must be obtained: energy response to different types of irradiation, radiation sensitivity, impact of such physiological factors as necrotic and metabolic processes, etc. In order to fill some of these existing gaps, this work is dedicated to the study of the energy dependence of EPR radio-induced signals of human bone tissue to photons and the determination of their relative sensitivity to fission neutrons. © 2007 Elsevier Ltd. All rights reserved.