RESUMO
The radiation exposures of children undergoing full spine radiography were investigated in two pediatric hospitals in Greece. Entrance surface kerma (Ka,e) was assessed by thermoluminescence dosimetry and patient's effective dose (E) was estimated by Monte Carlo simulation. All required information regarding patient age and sex, the irradiation geometry, the x-ray spectra, and other exposure parameters (tube voltage and current) were registered as well. Values of Ka,e were measured to range from 0.22 mGy to 2.12 mGy, while E was estimated to range from 0.03 mSv to 0.47 mSv. In general, all values were greater in one of the two hospitals, as higher tube currents and exposure times were used in the examinations because of the difference in radiographers' training and practice. Moreover, dose to red bone marrow was found to be between 0.01 to 0.23 mSv and dose to breast ranged between 0.02 and 1.05 mSv depending on the age, projection, and hospital. These values are comparable with literature sources.
Assuntos
Simulação por Computador , Hospitais Pediátricos , Método de Monte Carlo , Doses de Radiação , Radiometria , Escoliose/diagnóstico por imagem , Raios X , Carga Corporal (Radioterapia) , Medula Óssea/diagnóstico por imagem , Mama/efeitos da radiação , Criança , Pré-Escolar , Grécia , Humanos , Radiografia , Radiometria/efeitos adversos , Radiometria/métodos , Radiometria/estatística & dados numéricos , Medição de RiscoRESUMO
The x-ray luminescence of Y2O2S:Eu phosphor screens is studied both in transmission and in reflection mode observation. Detailed experimental data concerning the dependence of the absolute efficiency on the tube voltage and the screen's thickness are presented and comparisons to another rare earth phosphor material (Y2O2S:Tb) are given. With the help of theoretical calculations based on the Hamaker-Ludwig model all the experimental data are explained and the intrinsic efficiency and scattering coefficients of the phosphor are estimated.
