Institute for Radiation Protection and Nuclear Safety (IRSN)
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Traçage de l’origine des Matières En Suspension (MES): OSR6 | Axe B - Action B.1.1 | Rapport scientifique final
No full textL’objectif de cette action était d’exploiter les nombreux contaminants disponibles sur la base de données OSR BDOH pour déterminer l’origine des particules en appliquant un modèle de traçage sédimentaire. Malheureusement la répartition des contaminants entre les stations et les méthodes de prélèvement sont trop hétérogènes et ne permettent d’exploiter que les éléments trace métalliques et le mercure. Avec ces éléments, les résultats obtenus sont similaires à ceux obtenus par les méthodes utilisées dans l’OSR5 avec :- A Arles, une prédominance de la Durance et de l’Isère, avec une moindre contribution de l’Ardèche, de la Saône et du Rhône amont.- A Jons, une prédominance de l’Arve, de la Bourbre et du Fier, avec une moindre contribution de l’Ain et du Guiers
Thermal scattering law for ice based on neutron time-of-flight experiments carried out at the SEQUOIA spectrometer at the Oak Ridge National Laboratory
No full textInternational audiencePrecise estimation of neutron thermalization in moderators relies on high-fidelity thermal scattering cross-section data governed by the thermal scattering law (TSL). The Institut de Radioprotection et de Sûreté Nucléaire (IRSN) has been working on the development of improved TSL for light water ice. Many polymorphic phases of light water ice exist depending on the thermodynamic conditions. The most common type of ice at standard pressure and temperature below water freezing point (273.15 K) is ice- Ih . It is essential to have high-resolution experimental double differential data for developing and/or validating TSL for moderator materials.Existing experimental double-differential scattering data for ice- Ih are extremely sparse and of limited quality. New high-quality double-differential measurements for ice- Ih over multiple temperatures and incident neutron energies would directly support the validation and improvement of ice- Ih TSL models for criticality safety applications. Series of time-of-flight (TOF) inelastic neutron scattering experiments on ice- Ih at temperatures starting at 271 K and down to 6 K, have been carried out at the SEQUOIA spectrometer at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL), United States. The experiments have been performed for incident neutron energies, E i = 11, 55, 160, 250, and 600 meV, to explore different excitation energies in the vibrational phonon spectrum. This paper presents the thermodynamic conditions and the details of the TOF measurements on ice- Ih and the derived phonon spectrum from the experimentally measured double differential data. A study of the variation of the phonon spectrum of ice- Ih as a function of temperature is highlighted, and a preliminary TSL evaluation is developed based on the experimental phonon spectrum
Accélérateurs de radiothérapie autoblindés ZAP-X® pour les traitements stéréotaxiques intracrâniens: Aménagement des locaux et radioprotection des travailleurs
No full textCe document est la propriété de l'IRSN et ne peut être communiqué, reproduit ou utilisé sans son autorisation écrite préalable. - This document is the property of IRSN and shall not be disseminated, copied or used without its prior formal approval.International audienceEn radiothérapie externe et radiochirurgie, les accélérateurs de particules sont habituellement placés dans un bunker pour des raisons de radioprotection des travailleurs et du public, du fait des rayonnements ionisants de haute énergie émis dans la salle de traitement. Depuis quelques années, la société américaine ZAP Surgical Systems, Inc. a mis au point un nouvel accélérateur, le ZAP-X®, comportant un blindage interne (accélérateur dit « autoblindé ») innovant permettant, selon le constructeur, de s’affranchir de la présence d’un bunker de radiothérapie. Aussi, l’aménagement des locaux et la radioprotection des travailleurs intervenant autour d’un ZAP-X® nécessitent d’être évalués.Ce rapport présente les recommandations et points de vigilance de l'étude de l’aménagement des locaux et de la radioprotection des travailleurs pour l’installation de plateformes ZAP-X® en France
Interactions endothélium vasculaire – cellules immunitaires : un point de contrôle clef des lésions digestives radio-induites
No full textInternational audienceRadiation-induced toxicity of the digestive tract is a major clinical concern as many cancer survivors have received radiotherapy for tumours of the abdominopelvic area. The coordination and orchestration of a tissue's response to stress depend not only on the phenotype of the cells that make up the tissue but also on cell-cell interactions. The digestive system, i.e., the intestine/colon/rectum, is made up of a range of different cell populations: epithelial cells, stromal cells, i.e. endothelial cells and mesenchymal lineages, immune cells and nerve cells. Moreover, each of these populations is heterogeneous and presents very significant plasticity and differentiation states. The pathogenesis of radiation-induced digestive lesions is an integrated process that involves multiple cellular compartments interacting in a complex sequence of events. Understanding all the cellular events and communication networks that contribute to the tissue's response to stress is therefore a major conceptual and methodological scientific challenge. The study of heterogeneous populations of cells in a tissue is now possible thanks to "single cell' RNA sequencing and spatial transcriptomics techniques, which enable a comprehensive study of the transcriptomic profiles of individual cells in an integrated system. In addition, the mathematical and bioinformatics tools that are now available for the large-scale analysis of data allow the inference of cell-cell communication networks. Such approaches have become possible through advances in bioinformatics algorithms for the analysis and deciphering of interaction networks. Interactions influence the tissue regeneration process through expression of various molecules, including metabolites, integrins, junction proteins, ligands, receptors and proteins secreted into the extracellular space. The vascular network is viewed as a key player in the progression of digestive lesions, which are characterised by infiltration of a range of immune cells. A better characterisation of endothelium/immune cell interactions in suitable preclinical models, as well as in humans, may help to identify some promising therapeutic targets for the prediction, prevention or treatment of digestive toxicity after radiotherapy.La toxicité digestive radio-induite est une préoccupation clinique majeure car de nombreux patients survivants du cancer ont bénéficié d’une radiothérapie pour des tumeurs de la zone abdominopelvienne.La coordination et l’orchestration de la réponse d’un tissu à un stress dépendent du phénotype des cellules qui composent ce tissu mais aussi des interactions cellule-cellule. Le système digestif, c’est-à-direl’intestin, le côlon etle rectum, est composé d’un ensemble de populations cellulaires différentes : cellulesépithéliales, cellules stromales, c’est-à-dire cellules endothéliales et lignées mésenchymateuses, cellulesimmunitaires et cellules nerveuses. En outre, chacune de ces populations est hétérogène et présente desdegrés de plasticité et des états de différenciation très variables. La pathogenèse des lésions digestivesradio-induites est un processus intégré impliquant de multiples compartiments cellulaires qui interagissent dans une séquence complexe d’événements. La compréhension de l’ensemble des événementscellulaires et des réseaux de communication qui contribuent à la réponse au stress du tissu constitue ainsiun défi scientifique conceptuel et méthodologique important. L’étude de populations hétérogènes de cellules dans un tissu est possible grâce aux techniques de séquenc¸ age de l’ARN de “cellules uniques” et detranscriptomique spatiale qui permettent une étude complète des profils transcriptomiques de chaquecellule individuelle dans un système intégré. En outre, les outils mathématiques et bio-informatiquesaujourd’hui disponibles pour analyser les données à grande échelle permettent d’inférer les réseauxde communication de cellule à cellule. Ces approches sont devenues possibles grâce aux progrès desalgorithmes de bio-informatique permettantl’analyse etle décodage des réseaux d’interaction. Ces interactions déterminent le processus de régénération tissulaire par l’expression de diverses molécules dontdes métabolites, des intégrines, des protéines de jonction, des ligands, des récepteurs et des protéinessécrétées dans l’espace extracellulaire. Le réseau vasculaire est considéré comme un acteur clef de laprogression des lésions digestives qui se caractérisent par l’infiltration de diverses cellules immunitaires.Mieux caractériser dans des modèles précliniques adaptés mais aussi chez l’homme les interactionsendothélium–cellules immunitaires permettra d’identifier des cibles thérapeutiques prometteuses afinde prédire, prévenir ou traiter la toxicité digestive après une radiothérapie
RENEB Inter-Laboratory Comparison 2021: Inter-Assay Comparison of Eight Dosimetry Assays
No full textInternational audienceTools for radiation exposure reconstruction are required to support the medical management of radiation victims in radiological or nuclear incidents. Different biological and physical dosimetry assays can be used for various exposure scenarios to estimate the dose of ionizing radiation a person has absorbed. Regular validation of the techniques through inter-laboratory comparisons (ILC) is essential to guarantee high quality results. In the current RENEB inter-laboratory comparison, the performance quality of established cytogenetic assays [dicentric chromosome assay (DCA), cytokinesis-block micronucleus assay (CBMN), stable chromosomal translocation assay (FISH) and premature chromosome condensation assay (PCC)] was tested in comparison to molecular biological assays [gamma-H2AX foci (gH2AX), gene expression (GE)] and physical dosimetry-based assays [electron paramagnetic resonance (EPR), optically or thermally stimulated luminescence (LUM)]. Three blinded coded samples (e.g., blood, enamel or mobiles) were exposed to 0, 1.2 or 3.5 Gy X-ray reference doses (240 kVp, 1 Gy/min). These doses roughly correspond to clinically relevant groups of unexposed to low exposed (0-1 Gy), moderately exposed (1-2 Gy, no severe acute health effects expected) and highly exposed individuals (>2 Gy, requiring early intensive medical care). In the frame of the current RENEB inter-laboratory comparison, samples were sent to 86 specialized teams in 46 organizations from 27 nations for dose estimation and identification of three clinically relevant groups. The time for sending early crude reports and more precise reports was documented for each laboratory and assay where possible. The quality of dose estimates was analyzed with three different levels of granularity, 1. by calculating the frequency of correctly reported clinically relevant dose categories, 2. by determining the number of dose estimates within the uncertainty intervals recommended for triage dosimetry (±0.5 Gy or ±1.0 Gy for doses <2.5 Gy or >2.5 Gy), and 3. by calculating the absolute difference (AD) of estimated doses relative to the reference doses. In total, 554 dose estimates were submitted within the 6-week period given before the exercise was closed. For samples processed with the highest priority, earliest dose estimates/categories were reported within 5-10 h of receipt for GE, gH2AX, LUM, EPR, 2-3 days for DCA, CBMN and within 6-7 days for the FISH assay. For the unirradiated control sample, the categorization in the correct clinically relevant group (0-1 Gy) as well as the allocation to the triage uncertainty interval was, with the exception of a few outliers, successfully performed for all assays. For the 3.5 Gy sample the percentage of correct classifications to the clinically relevant group (≥2 Gy) was between 89-100% for all assays, with the exception of gH2AX. For the 1.2 Gy sample, an exact allocation to the clinically relevant group was more difficult and 0-50% or 0-48% of the estimates were wrongly classified into the lowest or highest dose categories, respectively. For the irradiated samples, the correct allocation to the triage uncertainty intervals varied considerably between assays for the 1.2 Gy (29-76%) and 3.5 Gy (17-100%) samples. While a systematic shift towards higher doses was observed for the cytogenetic-based assays, extreme outliers exceeding the reference doses 2-6 fold were observed for EPR, FISH and GE assays. These outliers were related to a particular material examined (tooth enamel for EPR assay, reported as kerma in enamel, but when converted into the proper quantity, i.e. to kerma in air, expected dose estimates could be recalculated in most cases), the level of experience of the teams (FISH) and methodological uncertainties (GE). This was the first RENEB ILC where everything, from blood sampling to irradiation and shipment of the samples, was organized and realized at the same institution, for several biological and physical retrospective dosimetry assays. Almost all assays appeared comparably applicable for the identification of unexposed and highly exposed individuals and the allocation of medical relevant groups, with the latter requiring medical support for the acute radiation scenario simulated in this exercise. However, extreme outliers or a systematic shift of dose estimates have been observed for some assays. Possible reasons will be discussed in the assay specific papers of this special issue. In summary, this ILC clearly demonstrates the need to conduct regular exercises to identify research needs, but also to identify technical problems and to optimize the design of future ILCs
Strengths of ecosystem services concept for radiation protection
No full textInternational audienceThe successful ecosystem services concept, defined as the benefits people obtain from ecosystems is still not really reflected in the current approaches for protecting public and environment against radiation promoted by the International Commission on Radiological Protection or other similar approaches. Yet some recent thoughts from international organizations lead us to believe that an eco-based approach could be more promoted in the coming years in environmental radiation protection field. The French Institute for Radiation Protection and Nuclear Safety has identified different fields of application of this concept into radiation protection, in line with its integrated approach of radiological risks management. As the ecosystem services approach makes it possible to highlight biophysical and socio-economic approaches of the impacts of ionizing radiation on ecosystems, it represents a subject of primary importance for future works conducted by IRSN. However, the operationality of the ecosystem services concept is the subject of many debates. In many situations, scientists have not yet fully understood how radioactive contamination could affect ecosystem services, and how to articulate with certainty cause and effect relationships between state of an ecosystem and provision of services. In addition, the concept is also accompanied by contradictory perceptions of the status of humans in ecosystems. To solve these knowledge gaps and uncertainties, it is necessary to acquire robust data on the impacts of radiation on ecosystems both under experimental and realistic conditions, and to integrate all potential consequences (direct and indirect, ecotoxicological but also economic and cultural)
Minimum Reporting Standards Should be Expected for Preclinical Radiobiology Irradiators and Dosimetry in the Published Literature
No full textInternational audiencePreclinical researchers have long acknowledged the critical need for accurate dosimetry in the conduct of radiation-exposure studies involving living systems. Although radiation dosimetry is required to be National Institute for Standards and Technology (NIST)-traceable for human irradiation protocols, there were previously only limited requirements stipulating accurate radiation exposures for preclinical radiation studies funded by the National Institutes of Health (NIH). In one of the earliest identified publications (1956) that addressed radiation dosimetry in murine studies, Hurst et al. (1) discussed their calculations surrounding estimating neutron responses, and “distribution of of absorbed energy versus LET”. In 2009, Zoetelief et al. (2) outlined European efforts to harmonize X-ray dosimetry studies in radiation biology, which resulted in the establishment of a protocol to improve dosimetry oversight and allow for better comparison of results across different institutions. It is, however, unclear if these early efforts substantially changed the approach of biologists to ensuring accurate and reproducible dosimetry in their radiation research.The lack of consideration of dosimetry in in vitro and in vivo work was further explored in 2011 during the “Radiation Dose is More than a Number” workshop convened by NIST, and co-sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), and the National Cancer Institute (NCI). The report that followed (3) made nine recommendations that ranged from coordinating with radiation physicists during the experimental design phase and including more setup and dosimetry details in publications, to establishing working groups to develop protocols, and implementing formal dosimetry intercomparison programs. In an attempt to address the latter suggestion, and ensure rigor and reproducibility in their funded research portfolio consistent with NIH grants policy , the NIAID Radiation and Nuclear Countermeasures Program (RNCP) released a request for proposals (NIAID-NIH-RFP-NIHAI201800020 ) in 2019, seeking to make a single contract award for “RNCP-Wide Dosimetry Guidance & Monitoring of Sources and Irradiation Protocols”. This funding opportunity requested that offerors develop a consistent means of dosimetry comparison and reproducibility, as well as provide the administrative foundation necessary to facilitate and coordinate dosimetry activities in partnership with the NIAID. Respondents were asked to provide services, facilities, expertise, and capabilities to develop a centralized dosimetry harmonization effort that fits the resources and circumstances of projects across the funded RNCP portfolio. The contract award was made in 2020 to the University of Wisconsin (Principal Investigator Larry DeWerd), who established a harmonization protocol to encompass all the irradiators in use across the RNCP-funded portfolio of grants, contracts, and inter-agency agreements.In 2019, the RNCP also became concerned with the specifics of establishing and reporting neutron dosimetry and convened a “Neutron Radiobiology and Dosimetry Workshop” with presentations from 17 subject matter experts, planned in collaboration with the Department of Defense (DoD), Defense Threat Reduction Agency (DTRA), and the National Aeronautics and Space Administration (NASA). The meeting report that was published in 2021 (4) explored historical neutron exposure research and highlighted the need for harmonized reporting of exposure and experimental parameters. The authors concluded that efforts should be made to update computer coding for neutron dosimetry estimates, government policies needed to be re-visited in terms of expected radiation energy spectrums, and funding agencies must make key investments in consideration of neutron dosimetry, to improve science and ensure radiation emergency preparedness.All of these early attempts to ensure the use of accurate dosimetry in research laboratories culminated in the current effort to take the next step and make strong recommendations that sufficient information be included in manuscripts or supplemental data files, such that reviewers and editors can be assured that the irradiations were carried out correctly, and so readers of the published work have the necessary information to replicate published experiments
A simplified mechanical system to determine the delayed impact of the content on the LID
No full textInternational audienceFor approved packages, the IAEA regulations require tests to simulate accident conditions to ensure that the consequences of such events are limited. In particular a 9-meter drop test must be performed. In case there is a significant gap between the contents and the lid, the kinematics of the impact could lead to a delayed impact of the content on the lid. So, the kinematic energy transmitted to the lid could be non-negligible due to the stiffness of the impact, thus leading to a strain of the screws which could no longer guarantee the safety performance of the package compared to a configuration with no gap. As the technical support organization of the French Nuclear Authority (ASN), IRSN is developing a tool to quickly evaluate whether complex, time-consuming and costly experimental tests or numerical analyses are required to evaluate the consequences of the delayed impact phenomenon on the safety level of the package design. This tool uses a simplified model based on Signorini's conditions. The content is modelled as beams discretized by finite elements and the contact is managed by a Lagrange multiplier to better represent the physical phenomena, at least compared to a simple mass/spring model, notably the contact time and the deceleration shape/amplitude. After demonstrating the validity of the model parameters, they will be adjusted through comparisons with actual drop tests that simulate the delayed impact. Then sensitivity analyses will be carried out to apprehend the influence of the damping, the incompressibility of the content, the non-linearity of the behaviour, etc
Radiation-induced neurotoxicity assessed by spatio-temporal modelling combined with artificial Intelligence after brain radiotherapy: the RADIO-AIDE project
No full textInternational audienceContext: Radiotherapy (RT) is one of the most important treatments of brain tumors. However, its potential toxicity on the central nervous system is a highly relevant clinical issue as cognitive dysfunction, mainly related to radiation-induced leukoencephalopathy (RIL), may alter the quality of life of patients. However, the physiopathology of post-RT brain injuries in normal tissues and organs is complex, multifactorial and partly understood as well as its potential links with the initiation and temporal progression of cognitive dysfunctions. Moreover, the knowledge about the radiosensitivity of the brain structures implied in cognitive processes must be improved.Objectives: The RADIO-AIDE project is a multidisciplinary project of 4 years, that started in April 2022. It aims to develop spatio-temporal (ST) models and artificial intelligence (AI) tools to : a) generate new knowledge about the underlying neurotoxic mechanisms implied in the initiation and temporal progression of cognitive dysfunctions following brain RT and the radioresistance of targeted brain structures, while accounting for the tumor-response status; b) predict individual cognitive impairment at early stage after brain RT to set up mitigation measures and preserve the patients’ quality of life; c) provide to clinicians a usable academic tool to perform an automated longitudinal extraction of clinically relevant image-based biomarkers - like white matter hyperintensities (WMH), vascular lesions, brain tissues volume quantification, tumoral lesions - from Magnetic Reasonance (MR) brain images acquired in clinical routine. Methods: The project will be guided by the rich and multimodal data from the prospective EpiBrainRad cohort including patients treated by RT for a high-grade glioma. Fully automated segmentation algorithms based on deep learning architecture will be developed. ST models and AI tools will be proposed to extract, if it exists, a set of ST features which characterize WMH of different nature that may be associated either to post-RT side-effects (RIL, radio-necrosis, post-RT oedema) or to treatment responses (brain tumor progression, peritumoral oedema). Finally, dose-response analyses and individualized predictions of cognitive dysfunctions following brain RT will be performed. Results and perspectives: An update of the EpiBrainRad cohort is in progress. New patients will be included from 2023. An annotated dataset including ground truth labels for post-RT WMH, vascular lesions and tumoral lesions as well as many brain regions of interest implied in cognitive functions is being produced from the MR brain images of the EpiBrainRad cohort. This large and well curated data set will feed the ST models and AI tools subsequently developed