Search results for " Medical Imaging"
showing 10 items of 1067 documents
Control flow strategy in a receiver coil for nuclear magnetic resonance for imaging
2020
A mathematical discussion is introduced to describe the receiver coil characterizing a nuclear magnetic resonance for imaging, starting from a general shape of the conductor. A set of different inductance calculations have been introduced, varying the shape of the conductor. The inductance calculation led to a general expression of the magnetic field of a single coil characterized by a rectangular shape. A dynamic model of the receiver coil has been developed to represent the natural frequencies that characterize the operational bandwidth. A nonstationary control strategy is implemented to make a real time changing of the operational bandwidth. The frequency response of the coil generates …
Sub-nanosecond excitonic luminescence in ZnO:In nanocrystals
2019
The financial support of research European Union ERA.NET RUS_ST20170-51 . This work was partly supported by Russian Foundation for Basic Research, Russia , project No. 18-52-76002 . The sample preparation was carried out as part of SFERA II project -Transnational Access activities ( European Union 7th Framework Programme Grant Agreement N3126430 ).
Digital and Handcrafting Processes Applied to Sound-Studies of Archaeological Bone Flutes
2016
Bone flutes make use of a naturally hollow raw-material. As nature does not produce duplicates, each bone has its own inner cavity, and thus its own sound-potential. This morphological variation implies acoustical specificities, thus making it impossible to handcraft a true and exact sound-replica in another bone. This phenomenon has been observed in a handcrafting context and has led us to conduct two series of experiments (the first-one using handcrafting process, the second-one using 3D process) in order to investigate its exact influence on acoustics as well as on sound-interpretation based on replicas. The comparison of the results has shed light upon epistemological and methodological…
Evaluation of the shielding in a treatment room with an electronic brachytherapy unit.
2017
Esteya® (Elekta Brachytherapy, Veenendaal, The Netherlands) is an electronic brachytherapy (eBT) system based on a 69.5 kVp x-ray source and a set of collimators of 1 to 3 cm in diameter, used for treating non-melanoma skin cancer lesions. This study aims to estimate room shielding requirements for this unit. The non-primary (scattered and leakage) ambient dose equivalent rates were measured with a Berthold LB-133 monitor (Berthold Technologies, Bad Wildbad, Germany). The latter ranges from 17 mSv h-1 at 0.25 m distance from the x-ray source to 0.1 mSv h-1 at 2.5 m. The necessary room shielding was then estimated following US and some European guidelines. The room shielding for all barriers…
Abnormal Textures Identification Based on Digital Hilbert Optics Methods: Fundamental Transforms and Models
2017
The article presents the abnormal textures identification technology based on structural and statistical models of amplitude-phase images (APIm) – multidimensional data arrays (semantic models) and statistical correlation analysis methods using the generalized discrete Hilbert transforms (DHT) – 2D Hilbert (Foucault) isotropic (HTI), anisotropic (HTA) and total transforms – AP-analysis (APA) to calculate the APIm. The identified fragments of textures are obtained as examples of experimental observation of real mammograms contains areas of pathological tissues. The DHT based information technology as conceptual chart description is discussed and illustrated with DHO domain images. As additio…
Ecografía intestinal y abdomen agudo: más allá de la apendicitis aguda
2021
Resumen El abdomen agudo es un motivo de consulta habitual en los servicios de urgencias. Sus causas son multiples, y entre ellas se encuentran diversas enfermedades del tracto gastrointestinal. Si bien la tomografia computarizada es la tecnica mas aceptada, con frecuencia se lleva a cabo una ecografia abdominal inicialmente, mediante la cual es posible establecer la sospecha de patologia intestinal. Este articulo describe las caracteristicas ecograficas de diversos trastornos intestinales que cursan con abdomen agudo, como la diverticulitis aguda, la obstruccion intestinal, la perforacion gastrointestinal, la isquemia intestinal, la necrosis aguda de la grasa intraabdominal y una miscelane…
Direct flow separation strategy, to isolate no-carrier-added 90Nb from irradiated Mo or Zr targets
2016
Abstract 90Nb has an intermediate half-life of 14.6 h, a high positron branching of 53% and optimal β + emission energy of only E mean 0.35 MeV per decay. These favorable characteristics suggest it may be a potential candidate for application in immuno-PET. Our recent aim was to conduct studies on distribution coefficients for ZrIV and NbV in mixtures of HCl/H2O2 and HCl/oxalic acid for anion exchange resin (AG 1 × 8) and UTEVA resin to develop a “direct flow” separation strategy for 90Nb. The direct flow concept refers to a separation accomplished using a single eluent on multiple columns, effectively streamlining the separation process and increasing the time efficiency. Finally, we also …
Complexation des acides aminés basiques arginine, histidine et lysine avec l’ADN plasmidique en solution aqueuse : participation à la capture de radi…
2016
L’environnement chimique de l’ADN en situation biologique est complexe notam-ment en raison de la presence d’histones, proteines nucleaires, associees en quantite approximativement egales a l’ADN pour former la chromatine. Les histones possedent de nombreux radicaux basiques arginine et lysine charges positivement et dont la majorite se trouve sur les chaines emergentes, l’ADN presente quant a lui des charges negatives sur ses groupements phosphates localises tout au long de la double helice. Dans cette etude, la complexite de la structure de la chromatine nucleaire est dans un premier temps mimee en solution aqueuse par la formation de complexes entre un ADN plasmidique sonde et les trois …
Morfofisiología del diafragma torácico en las medicinas china y occidental
2016
Resumen Las autoras creen que el analisis comparativo de diversos temas entre la medicina china y la occidental supone una aportacion al progresivo —y deseado— avance hacia la mutua comprension y sinergia entre ambas disciplinas. La descripcion occidental del diafragma toracico sugiere ciertas lineas de confluencia respecto al enfoque chino: anatomicamente aportan sugerentes paralelismos las referencias de insercion muscular e inervacion del diafragma, asi como su biodinamica respiratoria, elementos coincidentes con la posicion de diversos puntos de acupuntura toracicos que presentan, ademas, posibles semejanzas en sus funciones fisiologicas reguladoras a diversos niveles, con las que la me…
Development of a fast characterization setup for radionuclide generators demonstrated by a 227Ac-based generator
2021
Abstract The development of a setup for a fast online characterization of radionuclide generators is reported. A generator utilizing the mother nuclide 227Ac sorbed on a cation exchange resin is continuously eluted by using a peristaltic pump. To allow continuous and pulse-free elution of a large volume over extended time periods a 3D-printed interface designed to remove pressure-oscillations induced by the pump was placed between pump and generator column to ensure undisturbed generator elution. The eluate of the generator is passed through a 3D printed flow cell placed inside a borehole Na(Tl)-scintillation detector for high counting efficiency. Alternatively, a HPGe detector suitable for…