463 research outputs found
Factores predictores de conductas promotoras de salud en docentes de enfermerÃa de tres universidades de Cali, Colombia
Introduction: Health promotion has been a constant concern in the human being. It allows to understand behaviors related to it and orientates towards the generation of health promoting behaviors (HPB) that promote personal well-being. Objective: To determine the predictor factors influencing the HPB of the teachers according to Pender’s health promotion model. Materials and methods: A correlational descriptive design was made with a representative sample of the teachers with current contract during the study. Instruments such as the EVPS II scale of Pender were applied to measure the dependent variable CPS, as well as for the independent ones such as sociodemographic, knowledge on health promotion, perception of health status and perception of self-efficacy. Results: They are descriptive, according to the coefficient of variation in each of the subdimensions of the behaviors: spiritual growth, interpersonal relations, responsibility in health, nutrition, management of stress and physical activity. The predictor factors were based on the multiple regression model. Conclusions: Favorable HPB were spiritual growth, interpersonal relationships and nutrition. Predictors that have effect on HPB were presented on the basis of teacher rankings, age, senior adult performance area, stratum, income and area of performance, mental health and psychiatry
Radially restricted linear energy transfer for high-energy protons: A new analytical approach
Radially restricted linear energy transfer (LET) is a basic physical parameter relevant to radiation biology and radiation protection. In this report a convenient method is presented for the analytical computation of this quantity without the need for complicated simulation. The method uses the energy-re-stricted LETL, as recently redefined in a 1993 ICRU draft document and supplements it by a relatively simple term that represents the energy of fast rays lost within distancer from the track core. The method provides a better fit than other models and is valid over the entire range of radial distance from track center to the maximum radial distance traveled by the most energetic secondary electrons.L r computed by this approach differs only a few percent from the values
Contribution to the international symposium on heavy ions research: space, radiation protection and therapy, 21–24 March 1994, Sophia-Antipolis, Franc
Solid State Microdosimetry With Heavy Ions for Space Applications
This work provides information pertaining to the performance of Silicon-On-Insulator (SOI) microdosimeters in heavy ion radiation fields. SOI microdosimeters have been previously tested in light ion radiation fields for both space and therapeutic applications, however their response has not been established in high energy, heavy ion radiation fields which are experienced in space. Irradiations were completed at the NASA Space Radiation Laboratory at BNL using 0.6 GeV/u Fe and 1.0 GeV/u Ti ions. Energy deposition and lineal energy spectra were obtained with this device at various depths within a Lucite phantom along the central axis of the beam. The response of which was compared with existing proportional counter data to assess the applicability of SOI microdosimeters to future deployments in space missions
BrachyView, a novel in-body imaging system for HDR prostate brachytherapy: Experimental evaluation
© 2015 American Association of Physicists in Medicine. Purpose: This paper presents initial experimental results from a prototype of high dose rate (HDR) BrachyView, a novel in-body source tracking system for HDR brachytherapy based on a multipinhole tungsten collimator and a high resolution pixellated silicon detector array. The probe and its associated position estimation algorithms are validated and a comprehensive evaluation of the accuracy of its position estimation capabilities is presented. Methods: The HDR brachytherapy source is moved through a sequence of positions in a prostate phantom, for various displacements in x, y, and z. For each position, multiple image acquisitions are performed, and source positions are reconstructed. Error estimates in each dimension are calculated at each source position and combined to calculate overall positioning errors. Gafchromic film is used to validate the accuracy of source placement within the phantom. Results: More than 90% of evaluated source positions were estimated with an error of less than one millimeter, with the worst-case error being 1.3 mm. Experimental results were in close agreement with previously published Monte Carlo simulation results. Conclusions: The prototype of HDR BrachyView demonstrates a satisfactory level of accuracy in its source position estimation, and additional improvements are achievable with further refinement of HDR BrachyView's image processing algorithms
Microdosimetry simulations of solar protons within a spacecraft
The microdosimetric spectra derived by silicon microdosimeter in a proton radiation field traversing heterogeneous structures were simulated using the GEANT4 toolkit
Efficacy of a Manualized and Workbook-Driven Individual Treatment for Social Anxiety Disorder
Social anxiety disorder is a prevalent and impairing disorder for which viable cognitive-behavioral therapies exist. However, these treatments have not been easily packaged for dissemination and may be underutilized as a result. The current study reports on the findings of a randomized controlled trial of a manualized and workbook-driven individual cognitive-behavioral treatment for social anxiety disorder (Hope, Heimberg, Juster, & Turk, 2000; Hope, Heimberg, & Turk, 2006). This treatment package was derived from an empirically supported group treatment for social anxiety disorder and intended for broad dissemination, but it has not previously been subjected to empirical examination on its own. As a first step in that examination, 38 clients seeking treatment for social anxiety disorder at either the Adult Anxiety Clinic of Temple University or the Anxiety Disorders Clinic of the University of Nebraska–Lincoln were randomly assigned to receive either immediate treatment with this cognitive-behavioral treatment package or treatment delayed for 20 weeks. Evaluation at the posttreatment/postdelay period revealed substantially greater improvements among immediate treatment clients on interviewer-rated and self-report measures of social anxiety and impairment. Three-month follow-up assessment revealed maintenance of gains. Clinical implications and directions for future research are discussed
Radiation dose enhancement at tissue-tungsten interfaces in HDR brachytherapy
© 2014 Institute of Physics and Engineering in Medicine. HDR BrachyView is a novel in-body dosimetric imaging system for real-time monitoring and verification of the source position in high dose rate (HDR) prostate brachytherapy treatment. It is based on a high-resolution pixelated detector array with a semi-cylindrical multi-pinhole tungsten collimator and is designed to fit inside a compact rectal probe, and is able to resolve the 3D position of the source with a maximum error of 1.5 mm. This paper presents an evaluation of the additional dose that will be delivered to the patient as a result of backscatter radiation from the collimator. Monte Carlo simulations of planar and cylindrical collimators embedded in a tissue-equivalent phantom were performed using Geant4, with an 192Ir source placed at two different source-collimator distances. The planar configuration was replicated experimentally to validate the simulations, with a MOSkin dosimetry probe used to measure dose at three distances from the collimator. For the cylindrical collimator simulation, backscatter dose enhancement was calculated as a function of axial and azimuthal displacement, and dose distribution maps were generated at three distances from the collimator surface. Although significant backscatter dose enhancement was observed for both geometries immediately adjacent to the collimator, simulations and experiments indicate that backscatter dose is negligible at distances beyond 1 mm from the collimator. Since HDR BrachyView is enclosed within a 1 mm thick tissue-equivalent plastic shell, all backscatter radiation resulting from its use will therefore be absorbed before reaching the rectal wall or other tissues. dosimetry, brachytherapy, HD
Studies of the dose-effect relation
Dose-effect relations and, specifically, cell survival curves are surveyed with emphasis on the interplay of the random factors — biological variability, stochastic reaction of the cell, and the statistics of energy deposition —that co-determine their shape. The global parameters mean inactivation dose, , and coefficient of variance, V, represent this interplay better than conventional parameters. Mechanisms such as lesion interaction, misrepair, repair overload, or repair depletion have been invoked to explain sigmoid dose dependencies, but these notions are partly synonymous and are largely undistinguishable on the basis of observed dose dependencies. All dose dependencies reflect, to varying degree, the microdosimetric fluctuations of energy deposition, and these have certain implications, e.g. the linearity of the dose dependence at small doses, that apply regardless of unresolved molecular mechanisms of cellular radiation action
- …