RESUMO
ABSTRACT The transition from analog to digital radiology has expanded the capabilities of radiological imaging but has also made it possible to increase the radiation dose received by patients. Image quality in radiology is determined by factors such as radiographic techniques (kVp and mAs), which directly impact the dose and image quality. This study focuses on pediatric radiological exams considering their greater radiosensitivity and longer life expectancy. The study aimed to investigate the correlation between image quality and applied radiographic techniques using the CDRAD contrast-detail phantom. The results showed a direct linear relationship between the increase in kVp and the corresponding increase in image quality. Nonetheless, there was a significant variation in image quality between current-time products ranging from 0.5 to 2.5 mAs, in contrast to the nearly linear relationship observed within the 2.5 and 10 mAs range
RESUMEN La transición de la radiología analógica a la digital ha ampliado las capacidades de las imágenes radiológicas, pero ha también permitió aumentar la dosis de radiación que reciben los pacientes. La calidad de la imagen en radiología está determinada por factores como las técnicas radiográficas (kVp y mAs), que impactan directamente en la dosis y la calidad de la imagen. Este estudio se centra en exámenes radiológicos pediátricos considerando su mayor radiosensibilidad y mayor espe ranza de vida. El estudio está dirigido a investigar la correlación entre la calidad de la imagen y las técnicas radiográficas aplicadas utilizando el detalle de contraste CDRAD fantasma. Los resultados mostraron una relación lineal directa entre el aumento de kVp y el correspondiente aumento de calidad de la imagen. No obstante, hubo una variación significativa en la calidad de la imagen entre los productos actuales que van desde 0,5 a 2,5 mAs, en contraste con la relación casi lineal observada dentro del rango de 2,5 y 10 mAs.
Assuntos
Pediatria/instrumentação , Intensificação de Imagem Radiográfica/instrumentação , Imagens de Fantasmas , Doses de Radiação , Tecnologia Radiológica/instrumentaçãoRESUMO
O objetivo desta pesquisa foi avaliar os níveis de concentração de radônio 222Rn em águas de poços da região metropolitana de Curitiba, Paraná. O trabalho apresenta os resultados das concentrações das medidas feitas em águas de poços da região. As concentrações de 222Rn nas amostras das águas de poços foram medidas por meio do monitor de radônio AlphaGUARD. Os cálculos das concentrações de atividade iniciais de radônio na água foram feitos a partir da curva de decaimento do 222Rn e do equilíbrio secular entre o 222Rn e o 226Ra, observados depois de 30 dias. Os resultados indicaram que cerca de 70% dos valores das concentrações de 222Rn ficaram acima do valor recomendado pela USEPA, de 11,1 Bq.L-1, representando risco radiológico causado por este radionuclídeo. O estudo de caso apresentado mostrou que medidas prévias de radônio são recomendadas para que um projeto de construção seja implementado. No caso em questão, observa-se que as concentrações de radônio diminuem cerca de 56% na primeira caixa d'água e 83% na segunda em relação ao poço. Esse fato mostra que as ações para mitigação de radônio são viáveis e não exigem grandes modificações nos sistemas usuais da construção civil.
This research objective was to assess the level of randon-222 concentration in well water of the metropolitan region of Curitiba, Paraná. Current work presents the results of indoor 222Rn activity ground water samples from artesian wells from aquifers of the region. The studies of radon activity in water were performed using the radon detector AlphaGUARD. The calculations of initial radon activity in water were done considering the 222Rn decay correction as well as equilibrium level of 222Rn and 226Ra observed after 30 days of measurements. Obtained results show that about 70% of measured activity levels of 222Rn are higher than the recommended value of 11.1 Bq.L-1, which represent the risk for the human health associated with this radionuclide. The case study showed that previous measurements of radon are recommended for a construction project is implemented. In this case, it is observed that the radon concentrations decrease about 56% in the first water tank and 83% in the second water tank over the well. This fact shows that the actions for mitigation of radon are viable and do not require major modifications to the usual systems of construction.
RESUMO
Proton computerized tomography deals with relatively thick targets like the human head or trunk. In this case precise analytical calculation of the proton final energy is a rather complicated task, thus the Monte Carlo simulation stands out as a solution. We used the GEANT4.8.2 code to calculate the proton final energy spectra after passing a thick Al absorber and compared it with the same conditions of the experimental data. The ICRU49, Ziegler85 and Ziegler2000 models from the low energy extension pack were used. The results were also compared with the SRIM2008 and MCNPX2.4 simulations, and with solutions of the Boltzmann transport equation in the Fokker-Planck approximation.
Assuntos
Alumínio/química , Modelos Estatísticos , Validação de Programas de Computador , Software , Tomografia Computadorizada por Raios X/métodos , Simulação por Computador , Prótons , Doses de Radiação , Reprodutibilidade dos Testes , Espalhamento de Radiação , Sensibilidade e EspecificidadeRESUMO
This work presents the recent results of computer simulations for the low energy proton beam tomographic scanner installed at the cyclotron CV-28 of IEN/CNEN. New computer simulations were performed in order to adjust the parameters of previous simulation within the first experimental results and to understand some specific effects that affected the form of the final proton energy spectra. To do this, the energy and angular spread of the initial proton beam were added, and the virtual phantom geometry was specified more accurately in relation to the real one. As a result, a more realistic view on the measurements was achieved.