X-ray beam qualities for dental radiology purposes / PadronizaÃÃo de qualidade de feixes de raios-X para uso em radiologia odontolÃgica

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

In order to establish characteristics or properties of equipment for diagnostic radiology, e.g. ion chambers and semiconductor detectors, calibration laboratories offer a set of well-defined radiation conditions, called X-ray qualities, which can be used for many Physics studies and medical purposes. These X-ray qualities can be determined in terms of: (a) X-ray beam mean energy; (b) spectral resolution, (c) 1st and 2nd Half-Value Layers (HVL), and (d) total filtration. The standardization of radiation qualities has been carried out in several fields of study, but little attention has been given to the area of dental radiology, mainly for medical and physical applications using single-phase units with half-wave rectification. For this reason, a single-phase dental unit with adjustable peak voltage and tube current, called âvariable potential X-ray equipmentâ, was developed in this work, aiming to define X-ray beam qualities for test and calibrations purposes. Quality control parameters, such as kVp, HVL and radiation leakage, were evaluated according to the quality criteria set by the Brazilian Ministry of Health. X-ray spectra at 50, 60 and 70 kVp were determined by using a CdTe semiconductor detector and they were compared with those obtained for ten commercial X-ray dental units. The results showed that the behavior of the variable potential X-ray equipment is similar to the one observed for commercial X-ray equipments. As a result of this study, a set of X-ray radiation qualities for the variable potential X-ray equipment was determined. The X-ray qualities spectra were utilized as reference for determination of a new set of X-ray qualities characterized for a constant potential X-ray equipment. Changes in total filtration and potentials applied to the X-ray tube from the constant potential X-ray equipment were carried out, aiming to define similar spectra for both constant and variable X-ray equipments. Thus, sets of X-ray qualities were standardized and implemented in two X-ray laboratories: one with the variable potential X-ray equipment and other with potential constant X-ray equipment. These reference X-ray beam qualities can be used for test and calibration purposes from scientific studies and services

ASSUNTO(S)

qualidades de raios-x equipamentos de raios-x odontolÃgico odontology odontologia espectrometria de raios-x engenharia nuclear dental x-ray units. x-ray qualities x-ray spectrometry

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