Radiation attenuation and scattering by nanoestructured materials.

Abstract

In recent years, the properties and applications of nanostructured materials have been the main object of intense research in several fields of human activity. Some properties of these materials are attractives for radiological protection purposes, especially in the design of lighter and stronger devices for individual protection (EPIs). Research on this material could lead to the replacement of lead apron, which the clinical and technical staff must use during radiologic procedures, especially in cases of interventional techniques. As we know, the lead apron is brittle and cumbersome. In Medicine, nanostructured materials have been studied and explored for the application in diagnosis and therapy of tumors. However, the absorption of radiation by these new materials is still not well and completely understood. Besides, the results obtained by several researchers do not always agree.The purpose of this project is the evaluation of X ray beam transmission and scattering, in the energy range between 20 and 200 keV, by microstructured and nanostructured materials. Metallic particles, with micrometer or nanometer sizes, will be incorporated into a polymeric resin, in proportions ranging from 1% to 50%, relative to the resin mass. The dispersion of the particles in the resin matrix will be analyzed by electron microscopic and radiographic images. Measurements of radiation attenuation and scattering by the samples will be performed in order to determine the effect of the following variables: material composition, particle size, material concentration in the resin and X ray beam energy. An ionization chamber and X ray spectrometer with a CdTe detector will be used for measurements. The experimental X-ray spectra, transmitted through these materials, will be compared with the theoretical ones, simulated by the Monte Carlo code Geant 4. Results obtained with this project will provide informations about radiation absorption and scattering by nanostructures, which will be helpful in the understanding of physical properties of these materials for better application in different areas.