Evaluación de la técnica de impresión 3D para su implementación en radioterapia

La impresión 3D es una tendencia para aplicaciones diversas. El presente trabajo evalúa la posibilidad de su uso en la modalidad de inyección de plástico dentro de la radioterapia. Examinamos las impresiones de dife-rentes tipos de impresoras, materiales y calidades de impresión, con la finalidad de determinar qué posibili-dad hay de usar esta técnica en la fabricación de ma-niquíes, accesorios para dosimetría, soportes para tra-tamientos específicos, entre otras aplicaciones que cu-bran las necesidades diarias en un centro de radiotera-pia

Mini Subcritical Nuclear Reactor

A mini subcritical nuclear reactor was designed using Monte Carlo methods. The reactor has light water as moderator, natural uranium as fuel, and a 239PuBe neutron source. In the design uranium fuel was modeled in an arrangement of concentric rings: 8.5, 14.5, 20.5 26.5, 32.5 cm-inner radius, 3 cm-thick, and 36 cm-high. Different models were made from a single ring of natural uranium to five rings. For each case, the neutron spectra, the neutron fluence distribution, the effective multiplication factor, the amplification factor, and the reactor power were estimated. The ambient dose equivalent rate outside the mini reactor was also estimated. The maximum value for the keff (0.78) was obtained when five rings of fuel were used; this value is close to 0.86 which belongs to a Nuclear Chicago subcritical reactor which requires almost twice the amount of uranium than the mini subcritical reactor

Response to Neutrons and γ-rays of Two Liquid Scintillators

UltimaGoldTM AB and OptiphaseTrisafe are two liquid scintillators made by Perkin Elmer and EG & G Company respectively. Both are commercially promoted as scintillation detectors for α and β particles. In this work, the responses to γ-rays and neutrons of UltimaGoldTM AB and OptiphaseTriSafe liquid scintillators, without and with reflector, have been measured aiming to use these scintillators as γ-rays and neutron detectors. Responses to γ-rays and neutrons were measured as pulse shape spectra in a multichannel analyzer. Scintillators were exposed to gamma rays produced by 137Cs, 54Mn, 22Na and 60Co sources. The response to neutrons was obtained with a 241AmBe neutron source that was measured to 25 and 50 cm from the scintillators. The pulse height spectra due to gamma rays are shifted to larger channels as the photon energy increases and these responses are different from the response due to neutrons. Thus, UltimaGoldTM AB and OptiphaseTrisafe can be used to detect γ-rays and neutrons

Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe

Synthesis and characterization of hafnium oxide films for thermo and photoluminescent applications

Hafnium oxide (HfO2) films were deposited by the ultrasonic spray pyrolysis process. The films were synthesized from hafnium chloride as raw material in deionized water as solvent and were deposited on corning glass substrates at temperatures from 300 to 600 1C. For substrate temperatures lower than 400 1C the deposited films were amorphous, while for substrate temperatures higher than 450 1C, the monoclinic phase of HfO2 appeared. Scanning electron microscopy showed that the film’s surface resulted rough with semi-spherical promontories. The films showed a chemical composition close to HfO2, with an Hf/O ratio of about 0.5. UV radiation was used in order to achieve the thermoluminescent characterization of the films; the 240nm wavelength induced the best response. In addition, preliminary photoluminescence spectra, as a function of the deposition temperatures, are shown

Preparation of CaSO4:Dy by precipitation method to gamma radiation dosimetry

This paper presents the results of the preparation and characterization of dysprosium-doped calcium sulfate (CaSO4:Dy) phosphor, which was obtained by homogeneous precipitation from calcium acetate Ca(CH3COO )2. Structural and morphological characteristics were studied using a scanning electronic microscope (SEM). The structure of all compounds was determined by X-ray diffraction method too. Thermoluminescence (TL) emission properties of CaSO4:Dy under gamma radiation effects were studied. This phosphor powder presented a TL glow curve with two peaks (Tmax) centered at around of 180 and 300 1C, respectively. The TL response of CaSO4:Dy as a function of gamma absorbed dose was linear in a wide range. Both emission and excitation spectrawere also obtained. Results showed that this new preparation method of CaSO4:Dy TL phosphor is less expensive, cleaner and safer than the conventional preparation method

LUMINISCENT CHARACTERISTICS OF CaSO4: Dy FILMS OBTAINED BY SPRAY PYROLYSIS METHOD

The present paper reports the experimental results of dysprosium doped calcium sulphate(CaSO4:Dy) films deposited by spray pyrolysis method. CaSO4:Dy films were deposited on three different surfaces: glass, aluminum and quartz substrates at temperatures in the range from 450 to 600 °C. Structural and morphological characteristics of CaSO4:Dy films were observed. Thermoluminescent characteristics of films were determined by irradiating ultraviolet energy region. Thermoluminescent glow curve of CaSO4:Dy films with glass and aluminum substrates showed a peak under environmental irradiation. Both TL response glow shape and intensity of CaSO4:Dy films UV irradiated as a function of substrates were studied

Efectos del espectro de rayos X sobre la dosis

Los equipos de rayos X para el diagnóstico se presentan en diferentes tamaños y formas que dependen del tipo de la exploración a realizar. El espectro de rayos X, es la distribución de energía de los fotones del haz y está formado por un espectro continuo de los fotones de frenado y un espectro discreto debido a los fotones característicos. El conocimiento del espectro de los rayos X es importante para comprender como afectan los cambios del voltaje (kVp), la corriente (mA), el tiempo (s), y el tipo de filtro en los mecanismos de interacción entre los rayos x y el cuerpo del paciente, el receptor de imagen u otro material que se interponga en el haz. A través del espectro se puede estimar la dosis absorbida en cualquier punto del paciente, la calidad de la imagen y la radiación dispersa (que se relaciona con la dosis que recibe el operador del equipo). En este trabajo se usó el método Monte Carlo, con el código MCNP5, para calcular el espectro de los rayos X que se produce cuando un haz monoenergético de electrones de 250 keV interactúa con blancos de Mo, Rh y W. Los espectros se calcularon, con y sin filtro, y se estimaron los valores de la dosis equivalente ambiental, así como el Kerma en aire