Efeito da filtração adicional nas doses de radiação e na qualidade das imagens nos exames videofluoroscópicos / Effect of additional filtration on radiation doses and image quality in videofluoroscopic studies

OBJETIVO: Investigar o efeito da adição de filtros de alumínio (1 mm) e cobre (0,4 mm) na redução das doses efetivas de radiação e na qualidade das imagens em exames videofluoroscópicos. MATERIAIS E MÉTODOS: Ao tubo de raios X adicionou-se câmara de ionização conectada a um eletrômetro para medir o produto kerma-área, com técnica de 65 kVp e 0,7 mA, sem e com adição dos filtros. Foi medida resolução espacial, a de baixo contraste e tons de cinza, utilizando os objetos de teste de Leeds. Quinze voluntários tiveram o produto kerma-área/minuto do estudo faríngeo comparados, dez com filtração e base e cinco com adição dos filtros associados. RESULTADOS: A adição dos filtros separados ou associados produziu expressiva redução do produto kerma-área, com ganho na qualidade das imagens videofluoroscópicas determinado pela maior separação dos tons de cinza e aumento da relação brilho/contraste da curva de cinza. CONCLUSÃO: A interposição adicional de filtros de alumínio e cobre, em especial quando associados, melhora a qualidade das imagens, com expressiva redução das doses de radiação necessárias à sua geração.

OBJECTIVE: The purpose of thys study was to investigate the effect of the addition of aluminum (1 mm) and copper (0.4 mm) filters on effective radiation doses and image quality in videofluoroscopy. MATERIALS AND METHODS: An ionization chamber coupled with an electrometer was added to x-ray tube to measure the kerma area product with 65 kV and 0.7 mA technique, without and with additional filtration. Low contrast, gray scale and spatial resolution were measured utilizing Leeds test objects. Fifteen volunteers underwent pharynx study, ten without and five with aluminum and cooper filters associated, and had the kerma area product/minute compared. RESULTS: The specified filters addition, either separated or associated, allowed an expressive decrease in kerma area product besides an actual improvement in the videofluoroscopic images quality determined by a better gray tones differentiation and increased brightness contrast ratio in the gray curve. CONCLUSION: Additional aluminum and copper filters interposition, especially when associated, results in improved image quality with expressive reduction in the required radiation doses.

Targetry for cyclotron production of no carrier-added cadmium- 109 from natAg[p, n] 109 Cd reaction

Solid targets that consist of powder and electrodeposited targets are used commonly to produce radionuclides by accelerators. Since silver is easily electrodeposited in cyanide baths and has a very excellent thermal conductivity, the electrodeposited target is preferable to produce [109] Cd. To avoid cracking of peeling of the target during bombardment, it should have a level surface and a good adhesion to substrate. Hence, suitable targetry has extraordinary importance for the interested radionuclide production. Excitation function of cadmium-109 via [nat] Ag [p,n][109] Cd reaction was investigated by using ALICE-91 code. The required thickness of the silver deposit was calculated by SRIM code. Theoretical yield was calculated by means of Simpson numerical integral method. Silver was electrodeposited on copper backing by the cyanide bath. The prepared targets were examined with morphology and thermal shock tests. The most favorable beam energy was determined as 15 MeV. The desired thickness was determined to be up to 48 micro m; the theoretical calculated yield was 2.69 micro Ci/ micro A.h. Scanning electron microscope [SEM] potomicrographs and thermal shock tests represented excellent quality of the electrodeposited target. The present study suggested a good potentiality of cadmium-109 production by induced proton on electrodeposited silver targets

Biodistribution of [64 Cu] pyruvaldehyde-bis [N4-methylthiosemicarbazone] complex in fibrosarcoma-bearing rats

[64]Cu-pyruvaldehyde-bis [N[4]-methylthiosemicarbazone] [64]Cu-PTSM] is one of the most important copper radiopharmaceuticals used in clinical experiments. In this work, copper-64 [T[1/2]=12.33 h] production has been presented followed by the synthesis of the complexing agent, PTSM, and its structure was confirmed by common spectroscopic methods followed by radiolabeling with [64] Cu-actetate. The tracer was finally administered to fibrosarcoma-bearing rats and the biodistribution was determined in critical tissues as well as tumor. The final radiopharmaceutical solution underwent common quality control tests for animal injection a radiochemical purity >95% was determined. A significant tracer tumor uptake was observed 2 hours post injection. Tumonmuscle and tumonblood ratios were shown to be 8 and 6 respectively. [64]Cu-PTSM prepared in this report is a good candidate for tumor therapy as well as diagnosis for national use

Radiotratamiento de Mafenida 10 por ciento Crema / Radiotreatment with mafenide 10 per center cream

La aplicacion de las radiaciones ionizantes con fines descontaminantes constituye una alternativa para garantizar la calidad microbiologica de muchas producciones farmaceuticas. Se realizo el radiotratamiento de mafenida 10 por ciento crema que no cumplia con las especificaciones de calidad microbiologica establecidas en el pais. Para ello se determino la carga microbiana y se realizo un estudio de dosis en el producto, evaluandose 3,5,7 y 10 KGy de radiaciones gamma, con el empleo de una fuente radioisotopica de Co(60). Se realizaron evaluaciones microbiologicas y quimicofisicas pretratamiento y postratamiento y se definio irradiar el producto con 3 KGy como dosis minima, de forma continua y en la instalacion "Producto-I" del Instituto de Investigaciones para la Industria Alimenticia

Obtençäo de cobre-64 com atividade específica alta utilizando o processo Szilard-Chalmers / Obtention of copper-64 with high specific activity using Szilard-Chalmers process

O uso de radioisótopos com alta atividade específica é de grande importância nos estudos de distribuiçäo de substâncias radioativas em seres vivos. Nos países que possuem reatores de baixo fluxo de nêutrons, a produçäo de cobre-64 com alta atividade específica é realizada utilizando-se o processo de ruptura de ligaçöes químicas induzidas por transformaçöes nucleares (n, lambida) conhecida como processo de Szilard-Chalmers. Neste trabalho, realizaram-se experimentos irradiando o composto bis-[N-benzoil-fenilhidroxilaminato]cobre(II) no Reator Nuclear 'IEA-R1, em fluxo de nêutrons têrmicos de 5x10**12n/cm2s., utilizando-se amostras sem e com tratamento térmico antes e/ou depois da irradiaçäo. Quando se irradiam amostras sem pré-aquecimento e com recozimento térmico por 6,5 horas obteve-se uma atividade específica em torno de 3.900 MBq/mg Cu, 21 hs após a irradiaçäo. Os resultados obtidos neste trabalho, mostram ser este composto viável à obtençäo de cobre-64, com alta atividade específica. A sua aplicabilidade dependerá da otimizaçäo do método e da preparaçäo do radiocobre na forma adequada para uso médico