Potential contribution of selected metallic restorative dentistry materials to X-ray fluorescence

Recent advances have led to the use of new materials in dental restoration which is an area of rapid growth. Applications include improving oral aesthetics and essential rehabilitation, whilst procedures range from the recovery of partial elements (inlays) to fitting dental implants. Ceramics, polymers and metallic materials have all been successfully employed in dental applications and benefit from new cost efficient manufacturing techniques. The application of radiographic techniques in dentistry and other medicine is also increasing, and the combination of new materials and radiation can lead to an elevated health risk. X-rays can interact with metallic materials producing X-ray fluorescence, which can increase the radiation dose in proximity to restorative material and increase the risk of live biological tissue becoming cancerous. The issue demands consideration so that the biological risks associated with such procedures are kept as low as possible. Comparisons of doses calculated for several materials have provided evidence that the Ti cp and NiCrTi alloys present less contribution to the increase of dose in surrounding soft tissue and the potential deleterious biological effects. On the other hand, Amalgam appears to be the most deleterious alloy

Cost-effective approach to lung cancer risk for a radiological dispersal device (RDD) scenario

A release of radioactive material into the environment can lead to hazardous exposure of the population and serious future concerns about health issues such as an increased incidence of cancer. In this context, a practical methodology capable of providing useful basic information from the scenario can be valuable for immediate decisions and future risk assessment. For this work, the simulation of a radiological dispersal device (RDD) filled with americium-241 was considered. The radiation dose simulated by the HotSpot code was used as an input to the epidemiological equations from BEIR V producing the data used to assess the risk of lung cancer development. The methodology could be useful in providing training for responders aimed to the initial support addressed to decision-making for emergency response at the early phase of an RDD scenario. The results from the simulation allow estimating (a) the size of the potentially affected population, (b) the type of protection action considering gender and location of the individuals, (c) the absorbed doses, (d) the matrix of lung cancer incidence predictions over a period of 5 years, and (e) the cost-effectiveness in the initial decision environment

Qualidade de frutos de banana ‘Prata’ submetidos à radiação gama antes do processo de climatização

O objetivo do trabalho foi avaliar o comportamento de frutos de banana ‘Prata’ submetidos a diferentes doses de radiação gama antes do processo de climatização, com relação a componentes de qualidade e aparecimento depodridões. Os frutos provenientes do município de Angra dos Reis, RJ, foram levados ao CTEx – RJ, para tratamento com radiação gama nas doses de 0,25 kGy e 0,50 kGy. No Laboratório de Pós-Colheita da UFRuralRJ, parte dessesfrutos foram expostos ao carbureto de cálcio (7g. m-3 de câmara) por 32h (climatização). Durante 10 dias, sob temperatura aproximada de 27º C, os frutos foram submetidos às avaliações de coloração da casca, índice de doenças,perda de massa fresca, firmeza com casca e clorofila total da casca. Frutos irradiados e posteriormente climatizados apresentaram manchas marrons na casca, oriundas tanto do processo de amadurecimento, quanto pela ocorrência de doenças. Menores perdas de massa fresca foram observadas nos frutos do controle e irradiação isolada na dose de 0,25 kGy. As referidas doses não impediram a perda de firmeza nos frutos. A radiação gama não se adequa à baixa tecnologia empregada pelos produtores de banana de Angra dos Reis.Palavras- chave: Musa spp. Irradiação. Amadurecimento

Distribution of 238U, 232Th, 40K, and 137Cs concentrations in soil samples nearby a nuclear laboratory, Capao Island, Brazil

Absolute soil concentrations of 238U, 232Th, 40K, and 137Cs samples were measured using high-resolution gamma spectrometry. The area of interest encompasses an embankment in a mangrove swamp in Guaratiba, Rio de Janeiro, called Capao Island, where nuclear, chemical and biological defense laboratories of the Brazilian Army Technology Center are in operation for more than 30 years. In order to ensure that no significant environmental impact has resulted from neutron physics experiments performed in a graphite exponential pile in addition to the operation of two cesium-driven irradiating facilities, radiation monitoring of the isotopes was carried out. A total of eight 250 ml soil samples were extracted within an area of 300 m x 300 m. No trace of 137Cs was detected and the measured levels of 238U were found to be close to the global mean. However, some data that slightly exceeded the expected normal range for 232Th (60 % of samples) and 40K (20 % of samples) should be attributed to the construction debris (cement, rocks, and sand) used in the embankment at the site. Since there is no handling of those isotopes at that site or adjacent facilities that could affect their presence, it was concluded that no detectable contamination has occurred

Simulated nuclear contamination scenario, solid cancer risk assessment, and support to decision

The detonation of an (hypothetical) improvised nuclear device (IND) can generate atmospheric release of radioactive material in the form of particles and dust that ultimately contaminate the soil. In this study, the detonation of an IND in an urban area was simulated, and its effects on humans were determined. The risk of solid caner development due to radiation was calculated by taking into account prompt radiation and whole-body exposure of individuals near the detonation site up to 10 km. The excess relative risk (ERR) of developing solid cancer was evaluated by using the mathematical relationship from the Radiation Effects Research Foundation (RERF) studies and those from the HotSpot code. The methodology consists of using output data obtained from simulations performed with the HotSpot health physics code plugging in such numbers into a specific given equations used by RERF to evaluate the resulting impact. Such a preliminary procedure is expected to facilitate the decision-making process significantly

Simulated nuclear contamination scenario, solid cancer risk assessment, and support to decision

The detonation of an (hypothetical) improvised nuclear device (IND) can generate atmospheric release of radioactive material in the form of particles and dust that ultimately contaminate the soil. In this study, the detonation of an IND in an urban area was simulated, and its effects on humans were determined. The risk of solid cancer development due to radiation was calculated by taking into account prompt radiation and whole-body exposure of individuals near the detonation site up to 10 km. The excess relative risk (ERR) of developing solid cancer was evaluated by using the mathematical relationships from the Radiation Effects Research Foundation (RERF) studies and those from the HotSpot code. The methodology consists of using output data obtained from simulations performed with the HotSpot health physics code plugging in such numbers into a specific given equation used by RERF to evaluate the resulting impact. Such a preliminary procedure is expected to facilitate the decision-making process significantly