RESUMO
The aim of this work was to perform a dosimetric evaluation of two cone-beam computed tomography scanners. The study was performed with two scanners: i-CAT classic and PreXion 3D. Air kerma-area product (PKA) was measured for all full-arch dental implant planning protocols. Surface air kerma was also estimated at the region of the eyes, salivary glands and thyroid using thermoluminescence dosemeters positioned on an anthropomorphic phantom. The PKA values for the i-CAT classic ranged from 24 to 180 µGy m(2) and, for the PreXion, from 70 to 138 µGy m(2). The large variation of these values was mainly caused by acquisition time and field of views. The surface air kerma values were from 0.08 to 3.39 mGy at the eyes, 0.50 to 3.96 mGy at the parotids, 0.11 to 2.95 mGy at the submandibular glands and 0.05 to 1.32 mGy at the thyroid. These values are comparable with those found in the literature.
Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Implantes Dentários , Radiometria/métodos , Ar , Algoritmos , Antropometria , Brasil , Calibragem , Desenho de Equipamento , Humanos , Imageamento Tridimensional/métodos , Imagens de Fantasmas , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador , Dosimetria Termoluminescente , Tomógrafos ComputadorizadosRESUMO
The aim of this study was to evaluate the image quality of 29 computed tomography (CT) scanners in Brazil and to perform estimations of patient dose and image quality of common CT examinations at these equipment. The volume CT air kerma indexes (C(VOL)) were estimated, using normalised weighted air kerma indexes, supplied by the ImPACT group. The image quality tests were performed using the phantom and accreditation protocol from the American College of Radiology (ACR). The C(VOL) values for head scans varied between 8.7 and 108 mGy. The Hi-res chest examinations presented C(VOL) values varying from 0.4 to 32 mGy. For abdominal scans, the estimated C(VOL) values varied between 4.1 and 94 mGy. This wide variation of air kerma between different centres is related to the scanner type and also to the scanning parameters. The results also showed that the image quality did not attend all ACR CT accreditation requirements.
Assuntos
Processamento de Imagem Assistida por Computador/métodos , Radiometria/instrumentação , Radiometria/métodos , Tomografia Computadorizada por Raios X/métodos , Abdome/efeitos da radiação , Ar , Brasil , Desenho de Equipamento , Humanos , Imagens de Fantasmas , Radiologia/métodos , Tomógrafos Computadorizados , Estados UnidosRESUMO
Soybeans IAC-8 were harvested in the growth stages R7 and R8 commercial harvesting time and at two other subsequent times to compare their physiological and technological characteristics. Seeds were stored at two moisture levels, 12% and 15%, for 6 months. Germination and vigor (acelerated aging, electrical conductivity), oil and free fatty acids, peroxide and iodine values were evaluated periodically. As expected, the time of harvesting and seed moisture content affected seed performance, while oil content did not correlate to physiological quality as did acidity, peroxide value and iodine number.
Um campo de produção de soja IAC-8 foi colhido nos estádios R7 e R8 "pontos de colheita comercial" e em duas épocas subsequentes; as sementes foram estudadas sob os pontos de vista fisiológico e tecnológico, logo após as colheitas e durante o armazenamento de 6 meses (graus de umidade inicial de 12% e 15%). O comportamento das sementes foi avaliado através de testes de germinação, vigor (envelhecimento acelerado, condutividade elétrica), teores de óleo e de ácidos graxos livres, indices de peróxidos e de iodo. O momento de colheita e o grau de umidade afetaram o desempenho das sementes mas o teor de óleo não se relacionou à qualidade fisiológica, o que ocorreu com os índices de peróxidos e de iodo.
RESUMO
This research was conducted in two experimental areas; the first had been under cultivation with Bradyrhizobium japonicum anually inoculated for several years and the second was cultivated with sugarcane for many years receiving only mineral fertilization. Mineral nitrogen (urea and ammonium) effect was compared with the effects of inoculant treatments (liquid and peat carriers) on plant development, yield and seed quality. After harvesting, seeds were stored under normal environmental conditions and tested periodically. Germination, accelerated aging, electrical conductivity and seedling emergence tests showed that seeds coming from the area where inoculation was practiced have better quality. Best plant performance regarding plant height at different growth stages and yield was also found in this area. Among the nitrogen sources studied, best results were obtained when peat was the inoculant carrier.
A pesquisa foi conduzida em duas áreas experimentais do Departamento de Agricultura, ESALQ/USP. A primeira, cultivada com soja anualmente inoculada com Bradyrhizobium japonicum, durante vários anos e, a segunda, anteriormente cultivada com cana-de-açúcar, recebendo apenas adubação mineral. Os efeitos da aplicação de uréia e de sulfato de amonio foram comparados com os da inoculação de sementes, utilizando-se, produtos veiculados em turfa ou em meio líquido; avaliaram-se o desenvolvimento das plantas, a produção final e a qualidade das sementes (testes de germinação e de vigor) logo após a colheita e durante o armazenamento. Os resultados permitiram constatar o melhor desempenho fisiológico das sementes produzidas em área anteriormente cultivada com soja, o mesmo ocorrendo com o desenvolvimento inicial das plantas. Dentre as fontes de nitrogênio avaliadas, a utilização de inoculante veiculado em turfa se mostrou mais favorável.
RESUMO
This research was conducted in two experimental areas; the first had been under cultivation with Bradyrhizobium japonicum anually inoculated for several years and the second was cultivated with sugarcane for many years receiving only mineral fertilization. Mineral nitrogen (urea and ammonium) effect was compared with the effects of inoculant treatments (liquid and peat carriers) on plant development, yield and seed quality. After harvesting, seeds were stored under normal environmental conditions and tested periodically. Germination, accelerated aging, electrical conductivity and seedling emergence tests showed that seeds coming from the area where inoculation was practiced have better quality. Best plant performance regarding plant height at different growth stages and yield was also found in this area. Among the nitrogen sources studied, best results were obtained when peat was the inoculant carrier.
A pesquisa foi conduzida em duas áreas experimentais do Departamento de Agricultura, ESALQ/USP. A primeira, cultivada com soja anualmente inoculada com Bradyrhizobium japonicum, durante vários anos e, a segunda, anteriormente cultivada com cana-de-açúcar, recebendo apenas adubação mineral. Os efeitos da aplicação de uréia e de sulfato de amonio foram comparados com os da inoculação de sementes, utilizando-se, produtos veiculados em turfa ou em meio líquido; avaliaram-se o desenvolvimento das plantas, a produção final e a qualidade das sementes (testes de germinação e de vigor) logo após a colheita e durante o armazenamento. Os resultados permitiram constatar o melhor desempenho fisiológico das sementes produzidas em área anteriormente cultivada com soja, o mesmo ocorrendo com o desenvolvimento inicial das plantas. Dentre as fontes de nitrogênio avaliadas, a utilização de inoculante veiculado em turfa se mostrou mais favorável.
RESUMO
Soybeans IAC-8 were harvested in the growth stages R7 and R8 commercial harvesting time and at two other subsequent times to compare their physiological and technological characteristics. Seeds were stored at two moisture levels, 12% and 15%, for 6 months. Germination and vigor (acelerated aging, electrical conductivity), oil and free fatty acids, peroxide and iodine values were evaluated periodically. As expected, the time of harvesting and seed moisture content affected seed performance, while oil content did not correlate to physiological quality as did acidity, peroxide value and iodine number.
Um campo de produção de soja IAC-8 foi colhido nos estádios R7 e R8 "pontos de colheita comercial" e em duas épocas subsequentes; as sementes foram estudadas sob os pontos de vista fisiológico e tecnológico, logo após as colheitas e durante o armazenamento de 6 meses (graus de umidade inicial de 12% e 15%). O comportamento das sementes foi avaliado através de testes de germinação, vigor (envelhecimento acelerado, condutividade elétrica), teores de óleo e de ácidos graxos livres, indices de peróxidos e de iodo. O momento de colheita e o grau de umidade afetaram o desempenho das sementes mas o teor de óleo não se relacionou à qualidade fisiológica, o que ocorreu com os índices de peróxidos e de iodo.