Exposição de profissionais de saúde a radiações ionizantes : confiança dos profissionais nas leituras de dosimetria individual

Resumo - O avanço tecnológico e científico no campo da Medicina tem favorecido a aplicação das radiações ionizantes nas áreas da Medicina Nuclear, Radiologia, Radioterapia e noutras especialidades relacionadas com a medicina de intervenção, como a Cardiologia. As Organizações de Saúde, com profissionais com risco de exposição a radiações ionizantes, são responsáveis, legislativamente, por assegurar a sua vigilância. Certificando a observação controlada das doses de exposição, os profissionais são monitorizados com dosímetros individuais e submetidos a vigilância médica. As leituras de dosímetria individual destes profissionais, originam por vezes, nos próprios, desconfianças e incertezas quanto aos valores medidos. Objectivo: avaliar o grau de confiança dos profissionais de saúde, expostos a radiações ionizantes, no sistema de monitorização individual. Metodologia: estudo observacional do tipo analítico- transversal, por questionário. Amostra de 190 Técnicos de Diagnóstico e Terapêutica de Cardiopneumologia, Medicina Nuclear, Radiologia, Radioterapia, expostos a radiações ionizantes, que exercem a sua actividade profissional em hospitais do concelho de Lisboa. Resultados: 51,1% dos Técnicos de Diagnóstico e Terapêutica não confiam nas leituras dos dosímetros, não se determinou uma relação estatisticamente significativa entre essa confiança, o tipo de dosímetro e a empresa que realiza as leituras. A confiança é maior nos que exercem em Organizações de Saúde públicas. 40,2% das Organizações de Saúde apresentam plano de vigilância médica, constatando-se uma falta de conformidade entre os Técnicos de Diagnóstico e Terapêutica, nalguns hospitais, relativamente à existência desse plano no respectivo hospital. A margem de erro associado ao estudo é de 5,09%, com um nível de confiança de 95%. -----------Abstract - The technological and scientific advances in the field of medicine has encouraged the application of ionizing radiation with a considerable positive contribution in the areas of Nuclear Medicine, Radiology, Radiotherapy and other specialties related to medical intervention like Cardiology. The Health Organizations that arise the risk of occupational exposure to ionizing radiation and is their responsibility to ensure monitoring, according the law. To ensure the monitoring of controlled doses of exposure, the exposed works use an individual dosimeter and undergo medical supervision. The individual dosimetry readings of health-care professionals, is sometimes questionable for themselves, arising distrust and uncertainty about the values measured. Objective: evaluate the degree of confidence of health professionals, exposed to radiation, on the system of individual monitoring. Methods: Observational study of cross-type analysis by questionnaire. Sample of 190 of technologists of Cardiopneumology, Nuclear Medicine, Radiology, Radiotherapy, exposed to ionizing radiation, which work in hospitals on the region of Lisbon. Results: 51.1% of technologists does not rely on the readings of their dosimeters, and wasn’t determined a statistically significant relationship between this trust, the type of dosimeter and the company that makes the readings(s) of their(s) dosimeter(s). The confidence in the readings is higher in public Health Organizations. 40.2% of the Health Organizations have medical monitoring plan and there is a disagreement between technologists, in some hospitals, relatively to the existence of this plan in their hospital. It was estimated that the u

Mapping the Pasture Steppe in Bayankhongor, Mongolia: comparison of classification methods, using Landsat-8 and geophysical data

Grasslands in semi-arid regions, like Mongolian steppes, are facing desertification and degradation processes, due to climate change. Mongolia’s main economic activity consists on an extensive livestock production and, therefore, it is a concerning matter for the decision makers. Remote sensing and Geographic Information Systems provide the tools for advanced ecosystem management and have been widely used for monitoring and management of pasture resources. This study investigates which is the higher thematic detail that is possible to achieve through remote sensing, to map the steppe vegetation, using medium resolution earth observation imagery in three districts (soums) of Mongolia: Dzag, Buutsagaan and Khureemaral. After considering different thematic levels of detail for classifying the steppe vegetation, the existent pasture types within the steppe were chosen to be mapped. In order to investigate which combination of data sets yields the best results and which classification algorithm is more suitable for incorporating these data sets, a comparison between different classification methods were tested for the study area. Sixteen classifications were performed using different combinations of estimators, Landsat-8 (spectral bands and Landsat-8 NDVI-derived) and geophysical data (elevation, mean annual precipitation and mean annual temperature) using two classification algorithms, maximum likelihood and decision tree. Results showed that the best performing model was the one that incorporated Landsat-8 bands with mean annual precipitation and mean annual temperature (Model 13), using the decision tree. For maximum likelihood, the model that incorporated Landsat-8 bands with mean annual precipitation (Model 5) and the one that incorporated Landsat-8 bands with mean annual precipitation and mean annual temperature (Model 13), achieved the higher accuracies for this algorithm. The decision tree models consistently outperformed the maximum likelihood ones.