Institute for Radiation Protection and Nuclear Safety (IRSN)
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Dose-volume predictors of cardiac adverse events after high-dose thoracic radiation therapy for lung cancer: a systematic review and meta-analysis
No full textInternational audienceBackground: Lung cancer is a leading cause of cancer mortality and may require high-dose thoracic radiation therapy (RT). However, RT significantly increases the risk of radiation-induced cardiac events, such as pericarditis, cardiomyopathy, and ischemic heart diseases. Despite evidence from clinical trials showing that higher RT doses are associated with poorer survival outcomes due to these cardiac effects, data on dose-volume predictors of such events in lung cancer remain sparse.Objective: To systematically synthesize the incidence of cardiac events following radiation therapy for lung cancer treatment and dose-volume metrics predictors of radiation therapy-induced cardiac events in lung cancer treatment. Methods:This systematic review, registered on PROSPERO (CRD42024565103), adhered to PRISMA guidelines to investigate cardiac events and its dose-volume predictors following high-dose radiation therapy in adults with lung cancer. Data were extracted from longitudinal observational studies and randomized controlled trials. A comprehensive literature search was conducted across MEDLINE, Cochrane CENTRAL, and Embase, with studies selected based on predefined criteria, focusing on clinical cardiac outcomes. Data extraction followed CHARMS guidelines, and study quality was reported using the PROBAST tool. Results were synthesized narratively, with meta-analyses performed where appropriate using R software to estimate pooled effect sizes, heterogeneity, and publication bias.ResultsThe systematic review included 21 studies and identified a significant association between high-dose thoracic radiation therapy (RT) and an increased incidence of cardiac adverse events in lung cancer patients. The review revealed that higher dose-volume parameters, notably higher mean heart doses (MHD), were predictive of major cardiac events such as pericardial effusion, arrhythmias, and acute coronary syndrome. The meta-analysis showed a significant 4% (95% confidence interval: 3%-6%) increased probability of the occurrence of cardiac events per additional Gray of MHD, with low heterogeneity among studies (I 2 = 23%). No publication bias was evidenced.Conclusion:This study underscores the importance of dose-volume parameters as predictors of cardiac adverse events following high-dose thoracic RT in lung cancer treatment. The findings highlight the need for careful consideration of heart dose constraints in RT planning to mitigate the risk of radiation-induced cardiotoxicity, thereb
Effets secondaires du traitement par iode radioactif dans le cadre d’un cancer de la thyroïde : Résultats du suivi a 6 mois de l’étude START
No full textInternational audienceContexteLes principaux effets secondaires connus de la thérapie à l'iode (I131) sont les dysfonctionnements salivaires et lacrymaux. Cependant, leur incidence reste imprécise, et il n'existe aucune étude évaluant la relation dose-réponse entre la dose absorbée par les glandes salivaires et ces dysfonctionnements potentiels. De plus, en tant qu’enjeu majeur de santé publique, la conservation d’une bonne qualité de vie après thérapie revêt un caractère important, notamment pour un cancer dont la survie est excellente. Cependant, les symptômes d’anxiété et de dépression, ainsi que la qualité de vie après traitement par l’I131 ont été peu étudiés. Les objectifs de notre étude sont d'estimer les incidences de ces événements de santé chez les patients atteints de cancer différencié de la thyroïde (DTC) six mois après une thérapie par I131, d'identifier leurs facteurs de risque, et d'évaluer les relations dose-effet.MéthodesCette étude porte sur 136 patients atteints de DTC traités par thérapie à l’I131 : 44 et 92 patients ont reçu respectivement 1,1 et 3,7 GBq. Les dysfonctionnements salivaires et lacrymaux ont été évalués à l’inclusion (T0), c'est-à-dire immédiatement avant la thérapie à l’I131, et 6 mois plus tard (T6) à l'aide de questionnaires validés et de prélèvements salivaires, avec et sans stimulation des glandes salivaires. Les symptômes d’anxiété et dépression, ainsi que la qualité de vie ont également été évalués par questionnaires validés à T0 et T6.La dose absorbée par les glandes salivaires a été estimée à l'aide de dosimètres thermoluminescents et d'une reconstruction dosimétrique. Les analyses statistiques comprenaient des analyses descriptives, ainsi que des régressions logistiques et linéaires multivariées à effets aléatoires permettant d’obtenir des odds ratios (OR) et des betas (β) avec leur intervalle de confiance à 95% (IC 95%).RésultatsA T6, 22% et 18% des patients ont rapporté respectivement une sensation de sécheresse buccale récente, ou une sécheresse oculaire récente. L'âge, la ménopause, les symptômes de dépression et d'anxiété, les antécédents de maladie systémique et le fait de ne pas avoir pris d’antidouleurs au cours des 3 derniers mois se sont avérés être des facteurs de risque ou des variables significativement associés aux troubles salivaires ou lacrymaux. Des associations significatives ont été trouvées entre l'exposition à l’I131 et les dysfonctionnements salivaires ajustés sur les cofacteurs : par exemple, pour une augmentation de 1 Gy de la dose moyenne aux glandes salivaires, on observait un OR=1,43 (IC 95% : 1,01 ; 2,04) d’avoir une sensation de bouche sèche, une diminution moyenne de ß= -0,08 (IC 95% : -0,12 ; -0,02) mL/min du flux salivaire stimulé, et une augmentation moyenne de ß= 1,07 (IC 95% : 0,42 ; 1,71) mmol/L de la concentration de potassium salivaire. Le score global d'anxiété et de dépression (échelle HAD) a diminué de manière significative à T6 par rapport à T0 (p=0,04). De manière statistiquement non-significative, le nombre de patients souffrant d'anxiété a diminué entre T0 et T6, tandis que le nombre de patients présentant des symptômes de dépression a augmenté sur la même période. Aucune association significative n'ait été trouvée entre l'exposition à l’I131 et les symptômes d'anxiété ou de dépression ou l'état nutritionnel, mais une association dose-réponse négative significative a été trouvée entre la dose absorbée par les glandes salivaires et le score de la composante mentale de la qualité de vie (ß= -0,17, 95 % IC -0,33;-0,01 pour une augmentation de 1 Gy).Conclusions Cette étude apporte de nouvelles connaissances sur la relation dose-effet entre la thérapie à l’I131 et les dysfonctionnements salivaires/lacrymaux ou la qualité de vie chez les patients atteints de DTC : pour une dose absorbée par les glandes salivaires croissante, nous avons trouvé une augmentation de la sensation de bouche sèche, une diminution du flux salivaire stimulé, une augmentation de la concentration de potassium salivaire, et une diminution du score de la composante mentale de la qualité de vie. En identifiant les facteurs de risque, cette étude encourage les cliniciens à adapter la thérapie pour les patients à risque de ces troubles
Overview of TRIPOLI-5, a Monte Carlo code for HPC
No full textInternational audienceCEA, IRSN and EDF have joined forces and started the development of the TRIPOLI-5® Monte Carlo particle transport code in 2022, with the goal of performing massively parallel simulations on hybrid computing architectures. TRIPOLI-5 benefits from the experience gained from previous investigations conducted on the PATMOS mini-app, concerning the portability of particle-transport algorithms in High Performance Computing environments. Currently, the main focus of TRIPOLI-5 is on reactor physics applications, including multi-physics feedback for stationary and non-stationary configurations. In the long run, TRIPOLI-5 will eventually cover a broader range of applications (encompassing radiation shielding and nuclear instrumentation) and thus supersede the current-generation Monte Carlo codes TRIPOLI-4®, developed at CEA, and MORET6, developed at IRSN. In this paper, we provide an overview of the current status of TRIPOLI-5 and highlight the trends for future developments
In vessel melt retention 0d model for integral pressurized water reactors
No full textInternational audienceThe In Vessel Melt Retention (IVMR) strategy developed for Light Water Reactors (LWR) is an appealing solution for the mitigation of many Severe Accident (SA) scenarios. Allowing the corium to remain in the Reactor Pressure Vessel (RPV), significantly reduces the stresses on the containment. This approach is typical of innovative reactors like the AP1000 and the Hualong One, both GW-size Pressurized Water Reactors (PWR). In this paper, the IVMR application for integral PWR (iPWR) is investigated. These kinds of reactors are characterized by an electrical power output generally lower than 300 MWe, an integral layout and the use of passive safety systems. During a postulated accidental sequence that leads to fuel melting, the molten corium relocates down to the lower plenum of the RPV. By flooding the reactor cavity where the RPV is immersed, the external face of the vessel is cooled, and corium is maintained inside the lower head. The overall phenomenology occurring during the IVMR in an iPWR is similar to the phenomenology in a high-power LWR, but a few differences can be highlighted due to the different design features. Among the differences, it is interesting to notice that the molten pool is rather shallow and does not occupy a full hemisphere. This has an impact on the heat flux profile along the vessel wall. Another difference is the rather thick oxide crust, for which the modelling approach is adapted with respect to what is usually done for the analysis of high-power reactors. The purpose of this paper is to develop a 0D model for the steady-state analysis of idealized cases in an iPWR. It has been developed in the framework of the SASPAM-SA Horizon Euratom project. It is part of the preliminary activities of Work Package 4, which examines the evaluation of the safety margin for several existing iPWR designs, considering available data and plausible assumptions for the unknown parameters. The aim of this model is to include the specific features of iPWRs and provide first estimates of safety margins. Heat transfer correlations depending on the aspect ratio H/R are used to consider the shallow geometry of the pool. The absence of a designed channel or baffle around the vessel requires the use of pool boiling correlations for the external cooling. This work will also prepare the next steps of SASPAM-SA, which is the identification of models in SA codes needing some improvements. Integral reactor calculations focused on the IVMR are also planned: they will be compared to the results of the present 0D approach. Finally, we mention that the developed model is not design specific: it may be easily adapted to various designs by changing some geometrical or material parameters. The 0D model was implemented in Python. This tool will be made available for other partners for applications to other designs of interest
Analyse d’ouvrage par Alexandre Largier. Pouvoirs au travail, coordonné par Fabien Brugière, Dominique Glaymann et Guillaume Tiffon
No full textLe texte seul est utilisable sous licence CC BY-NC-ND 4.0. Les autres éléments (illustrations, fichiers annexes importés) sont « Tous droits réservés », sauf mention contraire.National audienc
Impact of experimental effects on a resolved resonance evaluation for practical applications
No full textInternational audienceNuclear data evaluations available in existing nuclear data libraries are derived based on differential measurements that includes experimental effects such as target temperature, time-of-flight resolution, data normalization, self-shielding, multiple scattering, etc. Measurements are often made at temperatures corresponding to room temperature, 293.6 K, to avoid complexity in the experimental setup and costs of carrying out measurements for temperatures other than room temperature. This paper investigates the impact of experimental effects on the evaluation of a set of resonance parameters that fit the experimental differential data and its use in integral benchmark calculations. Given the importance of the temperature in integral benchmark results, the impact of the Doppler effect will be examined. Very seldom are experimental differential data available for temperatures below or above room temperature. Nuclear data measurements and evaluation needs are driven by reactor applications; consequently, the majority of data evaluations in nuclear data libraries are for temperatures above room temperature. Recently there has been a demand for nuclear data for low temperatures, below room temperatures, for criticality safety applications. Currently, calculations in response to low-temperature needs are based on extrapolating the existing data from the nuclear data libraries to temperatures below 293.6 K. For temperatures above 293.6 K, common practice is to process the data library to temperatures different from the temperature it was evaluated and use them in practical applications. Although this is an acceptable practice, care should be taken to understand whether the validity of the nuclear data can be extended to low and high temperatures. Issues in connection with temperature effects for low and high temperature nuclear data and their impact on practical applications are addressed in the paper. Given that experimental data for low- and high-temperatures are scarce, the results of the presented approach are based on data simulations. Simulated data for 235U in the resonance region, in particular the resolved resonance region, were used as part of the studies and demonstration. Furthermore, temperature effects were also investigated for thermal neutron scattering data, for light water. However, the thermal scattering data are not based on simulation, but are the result of measurements carried out at the Spallation Neutron Source. A continuous-energy nuclear data library was used in Monte Carlo calculations to assess the impact in integral benchmark results
Mise à jour des données relatives aux expositions à la silice cristalline dans l’air extérieur chez les riverains de sites d’activités émettrices de silice cristalline
No full textCitation suggérée : Anses. (2024). Mise à jour des données relatives aux expositions à la silice cristalline dans l’air extérieur chez les riverains de sites d’activités émettrices de silice cristalline (saisine 2023-SA-0052). Maisons-Alfort : Anses, 78 p.L’Anses a publié en 2019 un rapport d’expertise sur les « dangers, les expositions et les risques sanitaires relatifs à la silice cristalline ». Concernant les risques pour la population générale, l’expertise conclut que les données recueillies sur les niveaux d’exposition à la silice cristalline de la population générale ne permettaient pas de réaliser une évaluation des risques sanitaires. De plus, l’expertise souligne qu’il n’existe pas de réglementation environnementale spécifique pour la silice cristalline en France. Dans le cadre de la réglementation relative aux Installations Classées pour la Protection de l’Environnement (ICPE), les installations d’extraction et de premier traitement de minéraux naturels, dans le cadre du régime d’autorisation, sont soumises à des dispositions particulières visant à contrôler l’émission de poussières susceptibles d'incommoder le voisinage et de nuire à la santé et à la sécurité publiques, mais il n’est pas fait mention de silice cristalline. Des mesures de concentrations en silice cristalline dans l’air ambiant peuvent être réalisées lors d’études d’impact, mais les données ne sont pas centralisées.Ainsi, dans son avis, l’Anses a recommandé pour la prévention des risques, y compris pour la population générale, de documenter les concentrations environnementales en silice cristalline dans l’air extérieur, au travers d’études réalisées aussi bien en station de fond qu’à proximité de sites susceptibles de générer des aérosols contenant de la silice cristalline, tels que les axes routiers et chantiers BTP. Puis, selon les résultats, d’évaluer l’intérêt d’inclure la silice cristalline dans le cadre de la surveillance de la qualité de l’air extérieur.Plus spécifiquement sur les carrières, l’Anses a recommandé, pour la protection de la population générale, de surveiller dans le cadre de la réglementation relative aux ICPE les émissions de silice cristalline, notamment à l’attention des riverains de ce type d’installation.L’Agence a également recommandé que les données issues de cette surveillance soient centralisées et accessibles.Suite à cette recommandation, la Direction générale de la prévention des risques (DGPR) a sollicité les fédérations professionnelles des industries de carrières (Union nationale des industries de carrières et des matériaux de construction (UNICEM) et fédération Minéraux Industriels-France (MIF)) afin d’évaluer les suites possibles à donner aux recommandations de l’Agence. Ces dernières ont conduit une étude visant à mesurer l’exposition à la silicecristalline autour d’une sélection de carrières réalisée par un bureau d’expertise. Cette étude fait l’objet d’un rapport en trois parties qui a été transmis à l’Anses (EVADIES, MIF et UNPG 2022a, 2022b, 2022c). [Saisine liée 2015-SA-0236
A comprehensive characterization of the neutron fields produced by the Apollon petawatt laser
No full textInternational audienceSince two decades, laser-driven neutron emissions are studied as they represent a complementary source to conventional neutron sources, with further more different characteristics (i.e. shorter bunch duration and higher number of neutrons per bunch). We report here a global, thorough characterization of the neutron fields produced at the Apollon laser facility using the secondary laser beam (F2). A Double Plasma Mirror (DPM) was used to improve the temporal contrast of the laser which delivers pulses of 24 fs duration, a mean on-target energy of ~10 J and up to 1 shot/min. The interaction of the laser with thin targets (few tens or hundreds of nm) in ultra-high conditions produced enhanced proton beams (up to 35 MeV), which were then used to generate neutrons via the pitcher-catcher technique. The characterization of these neutron emissions is presented, with results obtained from both simulations and measurements using several diagnostics (activation samples, bubble detectors and Time-of-Flight detectors), leading to a neutron yield of ~4.10 neutrons/shot. Similar neutron emissions were observed during shots with and without DPM, while fewer X-rays are produced when the DPM is used, making this tool interesting to adjust the neutrons/X-rays ratio for some applications like combined neutron/X-ray radiography
Capabilities and improvement ability of classical many-body potentials: application to hcp-Zr
No full textInternational audienceClassical interatomic potentials (CIPs) have a low-to-intermediate number of parameters and fixedfunctional forms that are based on the physical understanding of the chemical bonding [1].Numerically lighter than machine learning potentials, they enable studies not otherwise accessibleat the atomic scale, such as uncovering plasticity mechanisms, or validating mesoscale models ofalloy mechanical properties [2]. Identifying the CIP parameters for a specific materialsystem/physical problem remains a challenging step, knowing that the flexibility of CIPs is limited.A better understanding of the actual capabilities of a given potential type to reproduce some targetcombination of properties would thus be relevant when selecting, using and/or fitting such apotential. Relatedly, ways to improve CIPs when their transferability is unsatisfactory are notclearly established. In this work, we select the case of a many-body central force potential and investigate its ability toreproduce bulk and defect properties in hcp zirconium: hcp is a crystallographic structure for whichangular dependence matters, whilst simple central force potentials (EAM, FS, etc.) are still widelyused in the scientific community for non-fcc metals. We first combine efficient model screeningtools to a variance-based sensitivity analysis to firmly establish some of the intrinsic limits of thisclass of CIPs. We recover the known effect of the potential cutoff on the accessible range of c/aratios and various stacking fault energies (important for both plasticity and irradiation).Interestingly, the influence of CIP parameters is different from one property to another; inparticular, vacancy and self-interstitial energetics are mostly affected by two distinct parameters. Wetherefore propose to use the results of sensitivity analysis to re-optimize existing CIPs and improvetheir transferability; this process is illustrated by refitting a CIP for the study of small irradiationdefects in hcp-Zr. Finally, we discuss the applicability of our approach to (i) more complexinteraction models with up to tenth of parameters (MEAM, BOPs, etc.) and (ii) the development ofentirely new potentials
EURAD state-of-the-art report: development and improvement of numerical methods and tools for modeling coupled processes in the field of nuclear waste disposal
No full textInternational audienceThe Strategic Research Agenda (SRA; https://www.ejp-eurad.eu/publications/eurad-sra) of the European Joint Programme on Radioactive Waste Management (EURAD; https://www.ejp-eurad.eu/) describes the scientific and technical domains and sub-domains and knowledge management needs of common interest between EURAD participant organizations.Theme number 7 is entitled "Performance assessment, safety case development and safety analyses". A list of research and development priorities and activities of common interest to be addressed within EURAD for theme 7 have been established. Amongst others, the Understanding and modelling of multi-physical Thermo-Hydro-Mechanical-Chemical coupled processes (THMC) occurring in radioactive waste disposal is a major and permanent issue to support optimization of design and safety case abstraction. To tackle this challenge a research work package entitled "DONUT : Development and improvement of numerical methods and tools for modelling coupled processes" has been conducted within the EURAD join programming initiative. The purpose of this work package is to improve/develop methods or numerical tools in order to go a step further in development of (i) relevant, performant and cutting-edge numerical methods that can easily be implemented in existing or new tools, in order to carry out high-performance computing to facilitate the study of highly coupled processes in large systems, (ii) numerical scale transition schemes for coupled processes, (iii) innovative numerical methods to carry out uncertainty and sensitivity analyses. In this paper the work carried out within the DONUT work package is put in perspective regarding the existing concept and literature on the field. It does not pretend to be exhaustive but rather to put emphasis on particular issues tackled during the project