OVERVIEW OF OCCUPATIONAL RADIATION EXPOSURE IN MEDICAL WORKERS IN SANTA CATARINA, BRAZIL, BETWEEN 2014 AND 2017.

This study assessed occupational radiation doses in Santa Catarina, Brazil, from 2014 to 2017. Data were collected from Sistema de Informação Estadual de Radiações Ionizantes (SIERI), a compulsory occupational dose registration system established in Santa Catarina in 2014. Most doses were registered as lower than the dosemeter recording level (RL; 99.

Study of effective dose of various protocols in equipment cone beam CT.

This study has the purpose of assessing the radiation absorbed dose in organs/tissues and estimating the effective dose using five different models of Cone Beam Computed Tomography equipment using protocols with similar purpose. For this purpose, 26 thermoluminescent dosimeters were inserted in the position of the organs/tissues of a female anthropomorphic phantom. From the measurements the contribution of wT×HT in the organs and tissues the effective dose were calculated.

Assessment of protocols in cone-beam CT with symmetric and asymmetric beams usingeffective dose and air kerma-area product.

This study aims to evaluate and compare protocols with similar purposes in a cone beam CT scanner using thermoluminescent dosimeter (TLD) and the air kerma-area product (PKA) as the kerma index. The measurements were performed on two protocols used to obtain an image of the maxilla-mandible using the equipment GENDEX GXCB 500: Protocol [GX1] extended diameter and asymmetric beam (14cm×8.5cm-maxilla/mandible) and protocol [GX2] symmetrical beam (8.

Assessments of medical exposures during interventional radiology procedures.

This study aims to contribute to the construction of a scenario regarding patient radiation exposure in Brazilian interventional radiology, aiming to provide data for the future drafting of specific legislation on interventional radiology because there is currently a lack of safety regulations for haemodynamics services in this country. Fourteen haemodynamics services in the states of Santa Catarina and Bahia were evaluated. The radiological devices were characterised through measurements of air kerma-area product, entrance surface air kerma (Ke), exposure time, spatial resolution (SR), low-contrast resolution and half-value layer.

Response of TL materials to diagnostic radiology X radiation beams.

The main objective of this study was to carry out a direct performance comparison among some known types of TLDs-three types of CaSO(4):Dy pellets, sintered Al(2)O(3) pellets, LiF:Mg,Ti (Harshaw TLD-100), CaF(2):Dy (Harshaw TLD-200) and CaF(2):Mn (Harshaw TLD-400)-in the energy and dose ranges of diagnostic radiology beams. Several dosimetric characteristics were evaluated, such as reproducibility, sensitivity, calibration curves, lower dose limits and energy dependence.

TL tandem systems for the determination of effective energy in X radiation beams.

Tandem systems usually comprise two detectors with different radiation energy responses and are utilized to determine the effective energy of unknown radiation beams. The aim of this paper was to evaluate the influence of absorbed dose on tandem curves obtained for different TL materials. In the studied dose interval, the results demonstrate that there is no significant influence of dose on the tandem curves.

A simple method for evaluation of half-value layer variation in CT equipment.

Tandem systems, each formed by a pencil ionization chamber with and without a specific covering, were developed and tested in standard radiation beams. These systems were designed to be used in computed tomography radiation beams, where the half-value layer (HVL) determination is not an easy task. The behaviour of the tandem systems in diagnostic radiology showed the possibility of their use to confirm HVL values previously determined by the conventional HVL measurement method in quality control programmes.

A new extended-length parallel-plate ionization chamber.

A special parallel-plate ionization chamber was developed. The motivation for the construction of this new chamber was mainly to fulfil the need of a reference system for computed tomography standard beams in the Calibration Laboratory of IPEN. However, the chamber was tested also in standard radiation beams of mammography and conventional diagnostic radiology.

Performance of a pencil ionization chamber in various radiation beams.

Pencil ionization chambers were recommended for use exclusively in the computed tomography (CT) dosimetry, and, from the start, they were developed only with this application in view. In this work, we studied the behavior of a pencil ionization chamber in various radiation beams with the objective of extending its application. Stability tests were performed, and calibration coefficients were obtained for several standard radiation qualities of the therapeutical and diagnostic levels.