Institute for Radiation Protection and Nuclear Safety (IRSN)
Not a member yet
7928 research outputs found
Sort by
Radiation protection in a cohort of healthcare workers: knowledge, attitude, practices, feelings and IR-exposure in French hospitals
No full textInternational audienceThe number of healthcare workers occupationally exposed to ionizing radiation (IR) is increasing every year. As health effects from exposure to low doses IR have been reported, radiation protection (RP) in the context of occupational activities is a major concern. This study aims to assess the compliance of healthcare workers with RP policies, according to their registered cumulative dose, profession, and perception of radiation self-exposure and associated risk. Every healthcare worker from one of the participating hospitals in France with at least one dosimetric record for each year 2009, 2014, and 2019 in the SISERI registry was included and invited to complete an online questionnaire including information on the worker’s occupational exposure, perception of IR-exposure risk and RP general knowledge. H p (10) doses were provided by the SISERI system. Multivariate logistic regressions were used. Dosimeter wearing and RP practices compliance were strongly associated with ‘feeling of being IR-exposed’ (OR = 3.69, CI95% 2.04–6.66; OR = 4.60, CI95% 2.28–9.30, respectively). However, none of these factors was associated with RP training courses attendance. The main reason given for non-compliance is unsuitability or insufficient numbers of RP devices. This study provided useful information for RP policies. Making exposed workers aware of their own IR-exposure seems to be a key element to address in RP training courses. This type of questionnaire should be introduced into larger epidemiological studies. Dosimeter wearing and RP practices compliance are associated to feeling being IR-exposed. RP training courses should reinforce workers’ awareness of their exposure to IR
Optimizing coupled fluid-structure simulations for nuclear relevant geometries
No full textInternational audienceThe numerical simulation of fluid-structure interactions (FSI) has gained interest to study flow-induced vibrations. Nevertheless, the high computational resources required by such simulations can represent a significant limitation for their application to industrial configurations. Therefore, simplified modeling approaches, when physically applicable, can represent an interesting compromise. This can be the case of slender structures (tubes, rods) often encountered in nuclear power plants. In this paper, an Euler–Bernoulli beam finite element model is implemented inside the computational fluid dynamics (CFD) code code_Saturne. With the goal of finding CFD methods less expensive than large eddy simulations (LES), unsteady Reynolds Navier–Stokes (URANS) and hybrid URANS/LES approaches are considered. The resulting fluid-structure model is able to calculate the vibration response of cantilever beams under a fluid flow, avoiding the necessity of CFD-finite element method (FEM) code coupling. The first part of the paper describes the model and its implementation: it allows to perform 2-way explicit fluid-structure coupling, using the Arbitrary Lagrangian-Eulerian approach to account for the structure deformations. Validation test cases are presented in the second part: first, the model is validated in terms of frequency, added mass, and damping for a cylinder vibrating in static air and water; then, the model is validated toward the vortex-induced resonance and lock-in mechanisms for a cylinder subjected to water cross-flow. The model is then applied to a real experimental configuration of two in-line cylinders in water cross-flow: the calculated vibrations are found to be in good agreement with the experimental measurements
Radiothérapie et femmes enceintes : enquête sur la fréquence de ces actes et les modalités de prises en charge
No full textsciencesconf.org:sfpm-js2024:546542International audienceIntroduction : La radioth´erapie externe de femmes enceintes est rare mais n´ecessite uneprise en charge particuli`ere afin de limiter l’exposition du fœtus. En 2023, l’IRSN a effectu´eune enquˆete afin d’´etablir un ´etat des lieux des pratiques fran¸caises.Mat´eriel et m´ethode :L’enquˆete a ´et´e diffus´ee par l’APMESSP, la SFPM, la SFRO et le SNRO, aupr`es des physiciens m´edicaux et des oncologue-radioth´erapeutes. Le questionnaire ´etait scind´e en cinq parties portant sur : la fr´equence des actes et les localisations tumorales trait´ees, les modalit´esde prise de d´ecision pour r´ealiser une radioth´erapie externe, les m´ethodes de r´eduction de ladose re¸cue par le fœtus, l’estimation de la dose fœtale et l’enregistrement des doses et enfinla communication aupr`es de la patiente.R´esultats : 26 r´eponses sont obtenues. Sept centres indiquent avoir d´ej`a r´ecus´e une radioth´erapie pour une femme enceinte. Ces dix derni`eres ann´ees, dix centres indiquentavoir trait´e des femmes enceintes (moins de cinq par centre) et un centre avoir demand´el’interruption de grossesse avant un traitement du sein. Les principales localisations tumorales trait´ees sont : le sein (5), la sph`ere ORL (3) et le cerveau (2). Sur les centres ayantd´elivr´e des traitements, six indiquent utiliser un crit`ere d’acceptabilit´e de r´ealisation parmi :seuil `a 100 mGy ou crit`ere sur la dose en fonction de l’ˆage du fœtus, ´evaluation du b´en´eficepour la patiente versus le risque pour le fœtus. Les raisons indiqu´ees pour une interruptionde grossesse sont : le risque vital pour la patiente, une radioth´erapie pelvienne, la dose fœtale. Pour le traitement du sein et des tumeurs c´er´ebrales, les techniques de radioth´erapieconformationnelle et par modulation d’intensit´e (IMRT) sont utilis´ees. Pour le traitement auniveau de la sph`ere ORL, l’IMRT est syst´ematiquement utilis´ee. Six centres sur dix utilisentdes strat´egies pour contrˆoler et r´eduire la dose fœtale : mesure sur fantˆome, contourage del’ut´erus et organes du fœtus (traitement du col ut´erin), protection abdominale avec tablierplomb´e, faible modulation, faible ´energie, pas de traitement en mode h´elico¨ıdal. Tous lescentres ont r´ealis´e une estimation de la dose re¸cue par le fœtus (sept indiquent l’avoir mesur´eavec une chambre `a ionisation sur fantˆome). Aucun centre ne r´ealise une mesure de dose invivo. Enfin, mˆeme si la patiente est syst´ematiquement inform´ee des risques pour le fœtus etla dose enregistr´ee dans son dossier, la signature d’un consentement ainsi que la transmissionde la dose re¸cue par le fœtus `a la m`ere ne semble pas syst´ematique.Conclusions : Les r´eponses obtenues, peu nombreuses, ne permettent pas d’´etablir un ´etatdes lieux repr´esentatif de la situation fran¸caise. N´eanmoins, cette enquˆete montre uneh´et´erog´en´eit´e dans la prise en charge des femmes enceintes par radioth´erapie et soulignele besoin de recommandations notamment sur les crit`eres d’acceptabilit´e des traitementsvis-`a-vis du fœtus ainsi que sur les moyens pour r´eduire la dose fœtale
A triple‐microstructure hydro‐mechanical constitutive damage model for compacted MX80 bentonite pellet/powder mixture
No full textInternational audienceA triple‐microstructure hydro‐mechanical constitutive damage model was proposed to describe the hydro‐mechanical behaviour of MX80 bentonite pellet/powder mixture, based on the results from a series of suction‐controlled oedometer tests and microstructure observations. Emphasis was put on the pellet damage behaviour. The model parameters were determined essentially based on these results. The model response was firstly verified with the obtained oedometer tests. Then, the results of Molinero‐Guerra et al. and Darde who carried out suction‐controlled oedometer tests and swelling pressure tests on similar bentonite pellet/powder mixture were employed to validate the proposed model. It appeared that the global volume behaviour and the development of swelling pressure with suction of the bentonite mixture could be well reproduced. The model allowed gaining insights into the microstructural evolutions under oedometer loading. The global compression behaviour was governed by the filling of inter‐grain pores at unsaturated state, but by the compression of grains themselves at saturated state. Conversely, when wetted under constant‐volume condition, inter‐grain pores and intra‐grain macro‐pores were closed, by the swelling of intra‐grain micro‐pores. Examination of the water‐retention property showed that water saturated the intra‐grain micro‐pores at suction 19 MPa, and then started filling intra‐grain macro‐pores. When inter‐grain pores and intra‐grain macro‐pores were all closed at suction 0.1 MPa, water finally came back to intra‐grain micro‐pores. On the whole, the hydro‐mechanical behaviour of the bentonite pellet/powder mixture can be well described by the proposed model
An isotope dilution mass spectrometry overview: tips and applications for the measurement of radionuclides
No full textInternational audienceThis article proposes a practical guide including good laboratory practices followed by a critical reviewabout the application of isotope dilution mass spectrometry (ID-MS) measurement to radionuclideanalyses. Several national and international scientific institutions (French Alternative Energies and AtomicEnergy Commission, French Radioprotection and Nuclear Safety Institute, European Commission,International Atomic Energy Agency, and Belgian Nuclear Research Centre) participated in this review bysharing their good laboratory practices. ID-MS is one of the primary ratio methods of measurement inthe International System of Units. It can produce highly accurate results, as potential sources of bias canbe controlled. Many hints are given to obtain the best performance. In addition, a script written with theopen source software Octave is provided to calculate the optimal parameters of the {sample–spike}mixture easily. Radionuclide analysis by ID-MS applies to many different fields (environmental, biological,reference materials, irradiated samples, process control, nuclear safeguards and nuclear forensics)
Same-day discharge strategy in a heart rhythm management clinic - what about patients' reported experience?
No full textInternational audienceBackground and aims Same-day discharge (SDD) has been adopted for many interventional cardiology procedures, however data on patients’ experience are scarce. The aim of this study was to investigate patient-reported experience of a SDD strategy following electrophysiology procedures (EP) in a Heart Rhythm Management Department. Methods Consecutive patients undergoing EP procedures in our centre, who fulfilled pre-defined eligibility criteria for SDD, were asked to complete the study questionnaire, right before hospital discharge. Procedures suitable for SDD ranged from non-invasive (electric cardioversion, tilt test) to invasive ones (EP studies, device replacement, rhythm recorders implantation, ablation of supraventricular tachycardias including atrial fibrillation). The questionnaire aimed to assess patients’ experience before and during the procedure, their satisfaction with the quality of the provided information and their comprehension of the given instructions regarding the post-discharge period and their medication. Results The study questionnaire was completed by 501 patients. The majority of participants described SDD as a good or a quite good experience (n=440, 87,8%), while 94,6% of them (n=474) would not hesitate to undergo a second SDD procedure, if necessary. A direct interview with a healthcare team member was viewed as the preferred method of obtaining information on the procedure. At discharge, 1 out of 10 patients were still unsure of the instructions given by the healthcare team, including their anticoagulation treatment. Patient reported satisfaction rates did not differ between invasive and non-invasive procedures. However, after an invasive procedure, patients seemed to significantly have a better understanding of post-discharge instructions. Conclusion Patients reported a high level of satisfaction with SDD EP procedures. However, significant efforts need to be made in order to ensure their understanding of post-discharge instructions.Figure : Patients' reported experienc
Early Development of Atherosclerotic Plaques in the Coronary Arteries after Radiotherapy for Breast Cancer (BACCARAT Study)
No full textInternational audienceIntroductionRadiotherapy (RT) for breast cancer (BC) can lead to an increased risk of coronary artery disease several years after RT. Long before the eventual occurrence of coronary radiation disease, a precise evaluation of calcified and non-calcified atheromatous plaques, quantifiable by coronary CT scan, could allow a better understanding of the early phases of radiation-induced atherosclerosis and the possible implementation of preventive measures.ObjectiveThe aim of this study was to evaluate the development of overall, non-calcified and calcified atherosclerotic plaques over 2 years after RT for BC and associations with cardiac exposure.MethodThis study included BC patients treated with 3D-CRT without chemotherapy or a history of cardiovascular disease. A contrast-enhanced coronary CT scan was performed before RT and then 2 years after RT. Plaque progression was defined at the individual level for patients with an increased number of plaques at 2-year follow-up. Dosimetric data were collected for the total heart, left ventricle, and each coronary artery (left main: LM, left anterior descending: LAD, circumflex: CX, right coronary: RC). Logistic regression models were used to assess the association between doses and risk of plaque progression with odds ratios (OR) and 95% confidence intervals (CI). This study included 101 patients (84 left and 17 right BC).ResultsThe mean age at inclusion was 58.4 years. The majority of patients were free of atherosclerotic plaque at baseline and at 2-year follow-up (63% and 58%, respectively). Two years after RT, 7 patients (100% left breast) showed plaque progression: for 6 patients this progression was observed in the LAD, the most highly exposed coronary artery (Dmean = 16.0 Gy), and for 1 patient in the RC. Progression of calcified and noncalcified plaques was observed in 5 and 4 patients, respectively. The analysis of associations between dose and risk of plaque progression showed statistically significant association only for doses to the LM and CX (OR = 2.32 IC95%: 1.08–4.97; P = 0.03) and (OR = 2.27 IC95%: 1.09–4.74; P = 0.03) and positive but not significant for the other structures.ConclusionOur study suggests an association between the exposure of certain coronary arteries and the risk of an increase in the number of atherosclerotic plaques 2 years after breast cancer RT, whether calcified or not. These results remain to be confirmed, however, given the very limited number of patients, further research is needed to improve the understanding of the early mechanisms of radiation-induced atherosclerosis
Cancer treatment including radiotherapy reduces residual inflammatory risk in women with breast cancer
No full textInternational audienceBackground Radiotherapy is believed to induce vascular injury in patients with cancer. However, the link between radiation therapy and cardiovascular risk remains unclear, particularly in women with breast cancer where the coronary arteries are directly radiated. Purpose To explore the direct impact of cancer treatment including radiotherapy (RT) on coronary inflammation and the residual inflammatory risk in women with breast cancer. Methods This prospective study included 101 breast cancer patients from the BACCARAT study treated with RT without chemotherapy. CCTA images were taken at baseline (before RT) and two years following RT. Coronary inflammation was measured in each coronary artery using the perivascular Fat Attenuation Index (FAI) Score, an established quantitative metric of coronary inflammation, corrected for age and gender. The residual inflammatory risk was quantified using the CaRi-Heart prognostic model that integrates FAI Score with clinical risk factors (diabetes, smoking, hyperlipidaemia, and hypertension) and coronary plaque burden, as previously described. Results Two years after RT, 83 patients had a complete set of paired analysable CCTAs. There was a marked parallel reduction of vascular inflammation at follow-up, as captured by the significant reduction in FAI score percentiles across all epicardial coronaries (p<0.0001 for RCA, p=0.031 for LAD, p=0.009 for LCX, a-c). Despite the increase in coronary calcification (p<0.001, d), the predicted 8-year risk for fatal cardiac events (CaRi-Heart Risk) was reduced by 14% in this population two years after radiotherapy (p=0.014, e). No change was observed in total epicardial adipose tissue (EpAT) volume (p=0.17), while there was no significant association between coronary inflammation and the amount of radiation exposure of the heart (f). Importantly, there was a meaningful risk reclassification 2 years after radiotherapy, with 45.9% of the high-risk patients reclassified to lower risk categories, and a parallel expansion of the "low" risk population from 8.5% to 24.4% (g). Conclusion This study demonstrates that cancer treatment including radiotherapy decreases baseline coronary inflammation and leads to significant reduction of the residual inflammatory risk in women with breast cancer, two years after treatment (h). The parallel increase of coronary calcification suggests plaque stabilization as coronary inflammation is reduced, and supports that vascular inflammation triggered by the tumour itself, rather than the radiotherapy, may partly explain increased cardiovascular risk in these women
Evaluation préliminaire de l'impact du changement climatique sur le fractionnement solide/liquide des radionucléides dans le fleuve Rhône (France)
No full textInternational audienceThis presentation presents a first assessment of the evolution of the solid/liquid fractionation of pollutants in the Rhône with regard to the projected flows between today and 2100 from the Explore 2 project. The presentation provides the climate scenarios selected for this assessment and a first projection of their impact on the properties of suspended sediments and, consequently, on the solid/liquid fractionation of pollutants transferred to the river according to a direct discharge scenario and a watershed erosion scenario.Cette présentation présente une première évaluation de l'évolution du fractionnement solide/liquide des polluants dans le Rhône au regard des débits projetés entre aujourd'hui et 2100 issues du projet Explore 2. La présentation fournit les scénarios climatiques retenus pour cette évaluation et une première projection de leur impact sur les propriétés des sédiments en suspension et, par conséquent, sur le fractionnement solide/liquide des polluants transférés au fleuve selon un scénario de rejet direct et un scénario d'érosion du bassin versant
A typical postwar workshop: Insights into Simon Hantaï’s oil paint palette
No full textInternational audienceSimon Hantaï (1922–2008) was a highly influential postwar painter in Paris whose innovative serial practice, creative curiosity and theoretical convictions inspired a number of his contemporaries. His art media are typical of the period, consisting of commercial artists’ products, sold in tubes and cans, which were available to artists in Europe and beyond. We have studied a series of samples from the brands Lefebvre-Foinet, Lefranc & Bourgeois and Valor using a combination of optical and electron microscopy, accelerator-mass spectrometry carbon-14 dating, infrared spectroscopy, structural analysis, chromatographic and mass spectrometry techniques. Of particular interest is the rare access to a coherent artist’s studio collection and its dating in relation to the painter’s works. We gained precise information on paint formulations, including main binders and pigments, as well as additives, such as free metal soaps, beeswax and pine resin. This suggests the value of further research into paint formulations and their identification in paintings from the second half of the 20th century. These materials were studied for their capacity as possible references for future analysis of the painter’s artworks. The high degree of hydrolysis of the oil binder and alteration, notably by saponification, leads us to question the significance of these materials and the handling of the data generated towards comparative studies. These samples have a history; considering them as pristine references for comparative studies with the works of artists of the period cannot be done at the expense of their own materiality — and in particular their physico-chemical evolution over time in their specific environmen