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[en] The aim of this work was to study photon and electron dose distributions in a phantom filled with water using the Monte Carlo Geant4 tool for electron energies ranging from 1 to 21 MeV and for photon energies ranging from 1.25 MeV to 25 MeV, corresponding to conventional radiotherapy Linac energies. The results of the Geant4 calculations were validated based on the relevant experimental data previously published. The results obtained were fitted and analytical models of dose distributions were developed for gamma radiation and electrons. For each of these models, one-dimensional (including dose depth profiles as a function of the depth inside the phantom) and two-dimensional (including the dose distribution as a function of depth and lateral position inside the phantom) dose distributions have been considered. Results are presented for photons and electrons of various energies. The coefficient of determination R illustrates an excellent match between the developed analytical model and the Geant4 results. It is demonstrated that the analytical models developed in the present study can be applied in various fields such as those used for calibration applications and radiation therapy. It is concluded that the analytical models developed allow for quick, easy and reliable clinical dose estimates and offer promising alternatives to the standard tools and methods used in radiotherapy for treatment planning.
[en] To compare the coronary vasodilation effects of spray with those induced by tablet administration in coronary CT angiography (CCTA). A total of 2024 patients who underwent CCTA were identified for this retrospective study, including 828 patients with spray (spray group) and 1169 with tablets (tablet group). Of these, 93 patients underwent CCTA at least twice using both spray and tablets. The number of measurable segments and diameters of all 18 segments was measured. The number of measurable segments was compared between groups. No statistically significant differences were evident between these two groups in terms of clinical characteristics. All coronary segments except the ramus intermedius (RI) and left posterior descending artery (L-PDA) were significantly larger in the spray group than in the tablet group (all p < 0.001). In peripheral and branch vessels, as well as in central and main coronary arteries, the diameters were significantly larger in the spray group than in the tablet group (all p < 0.001). Although not always statistically significant, all coronary segments tended to be more measurable on CCTA with spray than with tablet. In the subgroup that underwent CCTA twice using both spray and tablets, all coronary segments except the RI, obtuse marginal artery 2 (OM2), and L-PDA were significantly larger in the spray group than in the tablet group (all p < 0.05). Lingual isosorbide dinitrate (ISDN) spray was more efficacious than sublingual nitroglycerin (NTG) tablets in coronary vasodilation for CCTA. Therefore, lingual ISDN spray should be preferred over sublingual NTG tablets for CCTA.
[en] Image-guided sternal biopsy may be technically daunting given the immediately subjacent critical structures. There is a paucity of literature describing technique, safety, and efficacy. This study aims to quantify the diagnostic yield and safety of image-guided sternal biopsies. Secondary aims include (1) describing the preferred approach/technique and (2) identifying imaging features and disease entities associated with higher and lower diagnostic yields. A retrospective review of 50 image-guided sternal biopsies performed at two quaternary care centers from 2000 to 2019 was performed. Recorded lesion-related variables included as follows: location, density, extraosseous extension, and size. Recorded variables from electronic medical records included as follows: patient demographics, histologic or microbiological diagnosis, and complications. Recorded technique-related variables included as follows: needle obliquity, type, and gauge; biopsy core number and length; and modality. Of the 50 biopsies, 88.0% resulted in a definitive histologic diagnosis. Six biopsies were non-diagnostic. The majority of biopsies were performed under computed tomography (88.0%), followed by ultrasound (12.0%). Tumor was the most common biopsy indication (90.0%), followed by infection (10.0%). Of the diagnostic biopsies indicated for tumor, 88.9% were malignant. Seventy-four percent of the lesions were predominantly lytic. Fifty percent of lesions had extraosseous extension. Lesion locations were as follows: manubrium (48.0%), sternal body (48.0%), and sternomanubrial joint (4.0%). No minor or major, acute, or delayed procedure-related complications were encountered. Image-guided sternal biopsy is an efficacious and safe method of obtaining a definitive histologic diagnosis regardless of lesion-specific features or location.
[en] RTE is the mainspring in enhancing energy transition and developing renewable energy in France. To further knowledge on the subject, RTE publishes a detailed inventory of existing and projected wind and photovoltaic installations. This vast overview was achieved with the help of ENEDIS (ERDF), SER (Association of renewable energy industrialists), and ORE Agency (Power network operators). The outstanding facts of this 24. edition of the renewable electricity synthesis are: 50% of renewable energy production capacity are from solar or wind origin. Solar and wind parks power reached almost 28 GW by December 31, 2020. With more than 25.7 GW of installed power, hydroelectricity remains the first renewable energy source in France. The bio-energy power generation park exceeds now 2.1 GW. All sources included, the renewable energy sources have grown by 637 MW during the last quarter 2020, reaching 55.9 GW at December 31, 2020. Power distribution systems are continuously evolving in order to meet the 40% renewable electricity production goal by 2030.
[en] To develop and test computer software to detect, quantify, and monitor progression of pneumonia associated with COVID-19 using chest CT scans. One hundred twenty chest CT scans from subjects with lung infiltrates were used for training deep learning algorithms to segment lung regions and vessels. Seventy-two serial scans from 24 COVID-19 subjects were used to develop and test algorithms to detect and quantify the presence and progression of infiltrates associated with COVID-19. The algorithm included (1) automated lung boundary and vessel segmentation, (2) registration of the lung boundary between serial scans, (3) computerized identification of the pneumonitis regions, and (4) assessment of disease progression. Agreement between radiologist manually delineated regions and computer-detected regions was assessed using the Dice coefficient. Serial scans were registered and used to generate a heatmap visualizing the change between scans. Two radiologists, using a five-point Likert scale, subjectively rated heatmap accuracy in representing progression. There was strong agreement between computer detection and the manual delineation of pneumonic regions with a Dice coefficient of 81% (CI 76–86%). In detecting large pneumonia regions (> 200 mm), the algorithm had a sensitivity of 95% (CI 94–97%) and specificity of 84% (CI 81–86%). Radiologists rated 95% (CI 72 to 99) of heatmaps at least "acceptable" for representing disease progression. The preliminary results suggested the feasibility of using computer software to detect and quantify pneumonic regions associated with COVID-19 and to generate heatmaps that can be used to visualize and assess progression.
[en] This publication presents the wind energy situation of continental France and overseas territories during the Fourth quarter 2020: number of newly connected wind farms and their production capacities (annual and quarterly evolution), distribution of wind farms per power range, wind farm park evolution trend, onshore and offshore pending projects (number and power), detailed regional results (number of farms, power, newly connected loads), annual and quarterly evolution of power generation and connected loads.
[en] Illustrated by many maps, graphs and tables, this publication proposes a rather detailed overview of the status and development (production and location, employment, sector turnover, market and tariffs) of the different electricity-producing renewable energies: wind energy, photovoltaic energy, hydraulic energy, solid biomass, biogas, renewable urban wastes, geothermal energy, marine energies). This issue includes a chapter on the Regional plan for land use and sustainable development (sraddet), and a regional overview of the different electricity-producing renewable sectors. A focus is proposed for each French region.
[en] Nuclear Energy Data is the Nuclear Energy Agency's annual compilation of statistics and country reports documenting nuclear power status in NEA member countries and in the OECD area. Information provided by governments includes statistics on total electricity produced by all sources and by nuclear power, fuel cycle capacities and requirements, and projections to 2040, where available. Country reports summarise energy policies, updates of the status in nuclear energy programs and fuel cycle developments. In 2020, the Covid-19 pandemic has highlighted the importance of electricity security in modern societies. Although the long-term implications for electricity generation are difficult to assess, during the crisis nuclear power continued to support the security of supply and has been, together with renewables, one of the most resilient electricity sources. In 2019, nuclear power continued to supply significant amounts of low carbon baseload electricity, despite strong competition from low-cost fossil fuels and renewable energy sources. Governments committed to having nuclear power in the energy mix advanced plans for developing or increasing nuclear generating capacity, with the preparation of new build projects making progress in countries such as Finland, Hungary, Turkey, the United Kingdom and Russia. Further details on these and other developments are provided in the publication's numerous tables, graphs and country reports. This publication contains 'StatLinks'. For each StatLink, the reader will find a URL which leads to the corresponding spreadsheet. These links work in the same way as an Internet link
[fr]Les Donnees sur l'energie nucleaire, compilation annuelle de statistiques et de rapports nationaux preparee par l'Agence de l'OCDE pour l'energie nucleaire, presentent la situation de l'energie nucleaire dans les pays membres de l'AEN et dans la zone de l'OCDE. Les informations communiquees par les gouvernements comprennent des statistiques sur la production d'electricite totale et nucleaire, les capacites et les besoins du cycle du combustible et, lorsqu'elles sont disponibles, des projections jusqu'en 2040. Les rapports nationaux proposent une synthese des politiques energetiques, de la situation des programmes electronucleaires et des evolutions du cycle du combustible. En 2020, la pandemie de COVID-19 a mis en avant l'importance de la securite de l'approvisionnement en electricite dans nos societes modernes. S'il est difficile d'evaluer les consequences a long terme sur la production d'electricite, on observe que, pendant la crise, l'energie nucleaire a continue de soutenir la securite d'approvisionnement et demeure, avec les renouvelables, l'une des sources d'electricite les plus resilientes. En 2019, les centrales nucleaires ont continue de fournir de grandes quantites d'electricite en base faiblement carbonee, et ce dans un contexte de forte concurrence avec les combustibles fossiles bon marche et les energies renouvelables. Les pays decides a inclure ou conserver le nucleaire dans leur bouquet energetique ont poursuivi leurs projets de deploiement ou d'augmentation de leur puissance nucleaire installee. Ainsi, des projets de construction progressent en Finlande, en Hongrie, au Royaume- Uni, en Russie et en Turquie. De plus amples informations sur ces evolutions et d'autres developpements sont fournies dans les nombreux tableaux, graphiques et rapports nationaux que contient cet ouvrage. Cette publication contient des 'StatLinks'. Fonctionnant comme un lien internet, un StatLink fournit l'acces a la feuille de calcul correspondante
[en] This publication presents a quarterly review of power generation from photovoltaic power plants connected to the French grid (continental France, Corsica and overseas territories): number of facilities and total connected load, quarterly and annual distribution of new connections, distribution of existing and new photovoltaic power plants per power range, trend of the photovoltaic solar power growth, pending projects (number and power), detailed regional results (number of facilities, power, newly connected loads), annual and quarterly evolution of power generation and connected loads, results revision.