Assessment of breast density in women from different regions of Brazil.

In many countries, there is an interest in determining the location of the women with the highest breast density. This investigation is important for optimize screening for breast cancer for women with dense breasts as other imaging modalities since 2D mammography is not very efficient on this type of breast. The objective of this study was to evaluate the variations in breast density in Brazilian women of different regions of Brazil.

Assessment of image quality and exposure parameters of an intraoral portable X-rays device.

Objective:: To evaluate the exposure parameters, radiation protection, absorbed dose and radiographic image quality of the DIOX intraoral portable radiography device.

Methods:: The exposure parameters were measured using the Xi UNFORS detector. Operator exposure to secondary radiation was measured using the 1800cc ionization chamber coupled to the electrometer.

Effective atomic numbers (Z) of based calcium phosphate biomaterials: a comparative study.

This study determined the interaction of radiation parameters of four biomaterials as attenuators to measure the transmitted X-rays spectra, the mass attenuation coefficient and the effective atomic number by spectrometric system comprising the CdTe detector. The biomaterial BioOss presented smaller mean energy than the other biomaterials. The μ/ρ and Z of the biomaterials showed their dependence on photon energy.

Monte Carlo derivation of filtered tungsten anode X-ray spectra for dose computation in digital mammography.

Objective: Derive filtered tungsten X-ray spectra used in digital mammography systems by means of Monte Carlo simulations.

Materials And Methods: Filtered spectra for rhodium filter were obtained for tube potentials between 26 and 32 kV. The half-value layer (HVL) of simulated filtered spectra were compared with those obtained experimentally with a solid state detector Unfors model 8202031-H Xi R/F & MAM Detector Platinum and 8201023-C Xi Base unit Platinum Plus w mAs in a Hologic Selenia Dimensions system using a direct radiography mode.

Mean glandular dose in six digital mammography services in Santiago, Chile: preliminary reference levels.

The purpose of this paper was to estimate mean glandular dose levels (DG) in six digital mammography systems in Santiago, Chile, and to propose preliminary reference levels to execute mammography in Chile. The study was carried out assessing two direct digital systems and four computer-based radiography (CR) systems. Estimates of DG were calculated for different thicknesses of polymethyl methacrylate according to the quality control protocol in digital mammography of the Spanish Society of Medical Physics and NHSBSP Equipment Report 0604 Version 3.

Dosimetry and image quality assessment in a direct radiography system.

Objective: To evaluate the mean glandular dose with a solid state detector and the image quality in a direct radiography system, utilizing phantoms.

Materials And Methods: Irradiations were performed with automatic exposure control and polymethyl methacrylate slabs with different thicknesses to calculate glandular dose values. The image quality was evaluated by means of the structures visualized on the images of the phantoms.

Comparison of mean glandular dose values provided by a digital breast tomosynthesis system in Brazil.

Studies are needed to determine the radiation dose of patients that are undergoing Digital breast tomosynthesis (DBT) procedures. Mean glandular dose (DG) values were derived from the incident air kerma (Ki) measurements and tabulated conversion coefficients. Ki values were obtained through an ionization chamber positioned in a Hologic Selenia Dimensions system using appropriate exposure parameters.