Xpektrin, un simulador de espectros fácil de usar y ampliamente distribuible para radiología general / Xpektrin, an easy to use and highly distributable X-Ray spectra simulator in general radiography

Resumen: Se presenta una aplicación basada en Microsoft Excel llamada Xpektrin para el cálculo de dosis en radiología general. La aplicación permite simular espectros de rayos X en radiología general utilizando el modelo TASMICS a partir de mediciones del kerma en aire (Kair) y de la capa Hemirreductora (HVL). Tiene implementado el cálculo de magnitudes radiométricas y dosimétricas, como el kerma en aire en la superficie de entrada (Ke) y la dosis en piel (Dskin), en función de la elección arbitraria de los factores de exposición, el tipo y grosor de filtro, la distancia foco-piel y el tamaño de campo. Xpektrin fue validado con la herramienta computacional SPEKTR 3.0, utilizando mediciones de dosis y de HVL de tubos de rayos X de tres recintos hospitalarios. Se encontró buena correlación en ambas aplicaciones entre las mediciones experimentales y los valores calculados de HVL y con coeficientes de Pearson R² ≥ 0.99 en todos los casos. Sin embargo, se obtuvo mejor concordancia con los valores experimentales de HVL con Xpektrin (mediana de diferencias -0.43%, -0.04% y 0.01%) que con SPEKTR 3.0 (mediana de diferencias -3.31%, 0.10% y -7.85%), en particular para el tubo con mayor filtración. Xpektrin está optimizada para ser utilizada en los departamentos de radiología para la determinación de dosis de pacientes individuales en función de los parámetros utilizados durante la exposición, por lo que puede ser utilizada como parte de un sistema de registro dosimétrico o como apoyo para el establecimiento de niveles de referencia para diagnóstico (NRD), siendo particularmente útil en servicios con equipos sin registros automáticos de dosis. Además, debido a sus características de simulador, puede ser útil como herramienta pedagógica. El uso de Excel permite que sea altamente distribuible y fácil de usar, sin necesidad de conocimientos de programación.

Abstract: Xpektrin, an easy to use and highly distributable X-Ray Spectra Simulator in General Radiography. An application based on Microsoft Excel called Xpektrin is presented for dose calculation in general radiology. The application was developed to simulate X-ray spectra in general radiography using the TASMICS model. Using as inputs air kerma (Kair) and Half-value layer (HVL) measurements, Xpektrin allows the calculation of several radiometric and dosimetric quantities, such as the entrance surface air kerma (Ke) and the skin dose (Dskin), depending on the exposure factors, filter material type, filter thickness, focus-skin distance and field size. Xpektrin was validated against the Matlab toolkit SPEKTR 3.0, using dose and HVL measurements of X-ray tubes from three different hospitals. It was found good correlation in both applications between the experimental measurements and the calculated HVL and Kair values with Pearson coefficients R² ≥ 0.99 in all cases. However, experimental and calculated HVL have better agreement with Xpektrin (median percent difference -0.43%, -0.04% and 0.01%) than SPEKTR 3.0 (median percent difference -3.31%, 0.10% and -7.85%), particularly for the tube with greater filtration thickness. Xpektrin is optimized to be used in radiology departments for patient dose determination depending on the exposure parameters and may be used as part of a dosimetric record system or as a support for the determination of Diagnostic Reference Levels, which may be useful when no automatic dose records are available. In addition, due to its simulator characteristics, it can be useful as a pedagogical tool. Using Excel allows Xpektrin to be highly distributable and easy to use, without the need for programming skills.

Influence of irrigants in association with ultrasound for cleaning root dentin surface after post space preparation: EDS analysis / Influencia de irrigantes en asociación con ultrasonido para la limpieza de la superficie de la dentina radicular después de la preparación del espacio para postes: análisis de espectroscopia de energía dispersiva

This study evaluated the cleanliness of post space after different irrigation protocols, associated or not to the use of ultrasound. Thirty-six single-rooted bovine roots were instrumented with rotary system, irrigated with 1 % hypochlorite and filled with Ah Plus sealer and gutta-percha cones. After seven days in stove at 37 °C, two-thirds of canal filling was removed by drilling and the post space preparation was irrigated with 2.5 % NaOCl (group NaOCl); 0.2 % chlorhexidine (group CLX); distilled water (group Water); 2.5 % NaOCl + ultrasound (group NaOCl-US); 0.2 % chlorhexidine + US (Group CLX-US); or water + US (Group Water-US). Roots were cleaved in mesiodistal direction, prepared for scanning electron microscope (SEM) to evaluate the smear layer and debris presence and for energy dispersive spectroscopy (EDS) analyses, to evaluate chemical components of dentin after treatment. The data were subjected to statistical analysis (two-way Anova and Tukey's test 5 %). EDS analysis showed the presence of chemical components of filling material in the samples from all groups. SEM images showed large amount of obliterated dentinal tubules. The use of ultrasound influenced the removal of some components of filling material (p<0.05), but not allowed for total cleaning. It was concluded that none of the irrigating solutions, associated or not to the use of ultrasound were able to completely clean the post space.

Este estudio evaluó la limpieza de la preparación para el espacio de los postes después de diferentes protocolos de irrigación, asociados o no al uso de ultrasonido. Treinta y seis raíces unirradiculares de bovinos fueron instrumentados con sistema rotatorio, irrigadas con un 1 % de hipoclorito y rellenadas con el sellador Ah Plus y conos de gutapercha. Después de siete días en horno a 37 °C, dos tercios de la obturación del canal se removió por perforación y la preparación del espacio para los postes fueron irrigadas con 2,5 % de NaOCl (grupo NaOCl); Clorhexidina 0,2 % (grupo CLX); agua destilada (grupo agua); 2,5 % NaOCl + ultrasonido (grupo NaOCl - US); 0,2 % de clorhexidina + US (Grupo CLX - US); y agua + US (grupo Agua - US). Las raíces se cortaron en dirección mesiodistal y se prepararon para el microscopio electrónico de barrido (MEB) con el fin de evaluar el barrillo dentinario y la presencia de restos; así como mediante el análisis de espectroscopía de energía dispersiva (EDS) para evaluar componentes químicos de la dentina después del tratamiento. Los datos fueron sometidos a análisis estadístico (pruebas ANOVA de dos factores y de Tukey al 5 %). El análisis EDS mostró la presencia de componentes químicos del material de relleno en las muestras de todos los grupos. Imágenes del MEB mostraron gran cantidad de túbulos dentinarios obliterados. El uso de la ultrasonido influyó en la eliminación de algunos de los componentes de material de relleno (p <0,05), pero no permitió la limpieza total. Se concluyó que ninguna de las soluciones de irrigación, asociadas o no a la utilización de los ultrasonidos fueron capaces de limpiar completamente el espacio para los postes.

Composition Analysis of Remaining Metal Particles on Ferrochrome Kitchen Knife / 法医学杂志

OBJECTIVE@#To establish a feasible evaluation index and method to identify composition of remaining metal particles on ferrochrome kitchen knife.@*METHODS@#The small samples of remaining metal particles were rubbed from the knives using filter paper. The composition of remaining metal particles was detected by scanning electron microscopy and energy dispersive X-ray spectrometer (SEM-EDX) and GSR particle analysis function, using mathematical methods to calculate the ratio (relative amount) of Fe and Cr in remaining metal particles.@*RESULTS@#The ratio (relative amount) of Fe and Cr of remaining metal particles had significant differences among most ferrochrome kitchen knives (P < 0.05).@*CONCLUSION@#Using GSR particle analysis function to quantitatively detect the ratio (relative amount) of Fe and Cr of remaining metal particles on ferrochrome kitchen knife, which can establish the feasible evaluation method to estimate such injury tool.

Some critical aspects of FT-IR, TGA, powder XRD, EDAX and SEM studies of calcium oxalate urinary calculi.

Urinary calculi constitute one of the oldest afflictions of humans as well as animals, which are occurring globally. The calculi vary in shape, size and composition, which influence their clinical course. They are usually of the mixed-type with varying percentages of the ingredients. In medical management of urinary calculi, either the nature of calculi is to be known or the exact composition of calculi is required. In the present study, two selected calculi were recovered after surgery from two different patients for detailed examination and investigated by using Fourier-Transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy and energy dispersive analysis of X-rays (EDAX) techniques. The study demonstrated that the nature of urinary calculi and presence of major phase in mixed calculi could be identified by FT-IR, TGA and powder XRD, however, the exact content of various elements could be found by EDAX only.

Microelements in primary teeth by inductively coupled plasmad Atomic emission spectroscopy

AIM: This study was carried out to estimate the concentrations three microelements in enamel of deciduous normal and carious teeth using atomic emission spectrometry. METHODS: A total of 80 deciduous molar teeth indicated for extraction from children between the age group of 713 yrs. were taken for this study. The specimens were divided into four groups and the samples were prepared using centrifuge flotation technique. They were analyzed for Manganese, Strontium and Zinc using inductively coupled plasma atomic emission spectroscopy. RESULTS: This study shows that sound enamel contains more of strontium when compared to the carious enamel. Carious enamel contains more of manganese, and zinc when compared to the normal enamel. Elements zinc and strontium occur in high concentrations, where as elements manganese occur in low concentrations in enamel. The concentrations of elements manganese, strontium and zinc does not vary in relation to sex of individual. CONCLUSION: The microelements strontium and zinc are present in high concentration. Further studies are necessary to see their potential in mineralization and anticariogenic process.

Progress in application of microbeam X-ray fluorescence spectroscopy in forensic science / 法医学杂志

Microbeam X-ray fluorescence (micro-XRF) spectrometry has been raised as an analytical technique of microbeam during the recent years. With its advantages of high sensitivity, small sample requirement, high testing accuracy and non-destruction, the technique is widely utilized in forensic science. This review bases on recent researches at home and abroad, describes its applications including identification of gunshot residue, visualization of fingerprints, discrimination of drug source, production process, and other material evidences of analysis in crime scene. Thanks to the advances in technology, intelligent and portable micro-XRF equipment has appeared to be applied. It is believed that it may be more popular and frequent in administration of forensic science in the near future.

Inspection of left metal particles on skin impacted by the steel hammers / 法医学杂志

OBJECTIVE@#To establish a new method to estimate injury-tool by analyzing the components of left metal particles from hammers impact on pig skin and filter paper using scanning electron microscope and energy dispersive X-ray spectrometer (SEM-EDX).@*METHODS@#The pig skin and filter paper were stricken by two steel hammers. The left metal particles were examined by SEM-EDX and the results were statistically analyzed by SPSS 13.0.@*RESULTS@#The characteristics of left particles showed stable by several impacts using one steel hammer. The left particles showed no statistical difference for impact on pig skin and filter paper. The left particles displayed a statistical difference using two hammer with different components.@*CONCLUSION@#SEM-EDX can be used to detect the left metal particles from the steel hammer and can provide a method for estimating injury-tool.

Imágenes de fluorescencia de rayos X en huesos humanos y su potencial aplicación in vivo / Images of X-ray fluorescence in human bones and their potential application in vivo

El conocimiento de la concentración y la distribución espacial de los elementos químicos presentes en diferentes órganos y tejidos resulta un parámetro útil para el diagnóstico de determinadas patologías o niveles por sobre los límites tolerables, por lo tanto el conocimiento de los elementos presentes en un tejido vivo, su concentración y distribución espacial podría proporcionar información relevante respecto del estado de salud de un individuo. Se presenta una aplicación de una nueva técnica de fluorescencia rayos X dispersiva en energía mediante barrido, la cual se puede aplicar a muestras de diferente composición y forma, a diferencia de, la mayoría de las técnicas existentes, que son aplicables sólo a muestras planas. Esta técnica permite la obtención de imágenes bidimensionales de los elementos químicos presentes en las muestras de un modo tanto mono como multielemental. En este trabajo es aplicada a un conjunto muestras óseas humanas y tarso y dedos de Gallus gallus (pollo) faenado, obteniéndose una distribución espacial 2D con diferentes niveles de intensidad fluorescente dependiendo del elemento detectado y de su concentración. Las imágenes logradas consideran áreas de hasta104 mm2, con una resolución espacial de hasta 0,25 mm2 y en un tiempo de adquisición de alrededor de 20 min. También se lleva a cabo un cálculo de la dosis de la radiación asociada a este tipo de análisis XRF, encontrándose que los niveles aplicados para la obtención de una imagen XRF son tolerables. Lo anterior permite concluir que sería posible el uso de esta técnica para una aplicación in vivo.

The knowledge of the concentration and spatial distribution that chemical elements present in different organs and tissues is a useful parameter for diagnosis of certain diseases or element levels above limits accepted as healthy. Therefore, development of techniques to identify the chemical elements present in a living tissue and obtaining information about their concentration and spatial distribution might be relevant to determine an individual's health status. This work presents an application of a new X-ray fluorescence technique, energy dispersive by scanning, which can be applied to samples of different composition and shape, unlike most of the existing techniques, only applicable to flat samples. This technique allows the acquisition of two-dimensional images of the chemical elements present in a sample in both mono and multi-elemental mode. In this work the technique is applied to a set of human bone samples and tarsus and fingers of a dead Gallus gallus (chicken), obtaining a 2D spatial distribution with different levels of fluorescence intensity, depending on the detected element and its concentration. The acquired images consider areas up to 104 mm2, with a spatial resolution of 400 mm2 and an acquisition time of about 20 min. Calculations of the radiation dose associated with this type of XRF analysis were also carried out, and the findings show that the levels applied to obtain an XRF image are tolerable. The latter leads to the conclusion that it would be possible to use this technique for an in vivo application.

Dosimetria de raios X em mamografia para combinação Mo/Mo utilizando espectrometria Compton / X-ray dosimetry in mammography for Mo/Mo combination utilizing Compton spectrometry

OBJETIVO: Para comparar o benefício da mamografia e o risco de câncer induzido por raios X, devese investigar as doses absorvidas. Nesse sentido, determinaram-se espectros dos raios X de um mamógrafo clínico, para combinação alvo/filtro Mo/Mo, utilizando espectrometria Compton, e avaliou-se a dose glandular média (DGM) em um simulador de mamas de BR-12. MATERIAL E MÉTODO:Um detector de CdTe foi usado para espectrometria dos raios X espalhados a ~ 100° por um cilindrode PMMA, para diferentes profundidades de BR-12 e tensões entre 28 e 35 kV. Após a reconstrução do espectro dos feixes primários, a partir dos medidos, determinou-se a DGM. RESULTADOS:Obtiveram-se camadas semirredutoras de 0,39 a 0,45 mmAl (espectrometricamente) e de 0,38 a0,42 mmAl (com câmara de ionização) para os feixes incidentes na superfície do simulador. A DGMNnormalizada por unidade de kerma no ar incidente, na superfície de BR-12, variou de 0,156 a 0,226.CONCLUSÃO: Os valores de DGMN variaram de 1% a 3%, em relação aos obtidos com câmara. O método empregado é uma boa alternativa para a determinação de DGMN e da distribuição de dose em profundidade em simuladores mamários.

OBJECTIVE: To compare mammography benefit and X-ray induced cancer risk, one should investigate absorbed doses. For this purpose, spectra of primary X-ray beams from a clinical mammographyequipment were determined for Mo/Mo target/filter combination,using Compton spectrometry and average glandular dose (AGD) in a BR-12 breast phantom was evaluated. MATERIAL AND METHOD: A CdTe detector was used for spectrometry of X-ray beams Compton scattered around 100°, by a PMMA cylinder, for different depths inside the BR-12 phantom and voltages between 28 and 35 kV. The reconstruction of the primary beam spectra from the measured ones was followed by the determination of AGD. RESULTS: Half-value layer values determined by spectra resulted 0.39 to 0.45 mmAl, and by ionization chamber, 0.38 to 0.42 mmAl, respectively, for beams incident on the phantom surface. The AGDN normalized per unitary incident air kerma, on the BR-12 surface, ranged from 0.156 to 0.226. CONCLUSION: The percentage deviation of AGDN, relative to the chamber measurements, ranged from 1% to 3%. The utilized method is a good alternative to determineAGDN and depth-dose distributions in breast phantoms.

Determination of acid-resistant silicic particles in lung by micro-XRF and its application in diagnosis of drowning / 法医学杂志

OBJECTIVE@#Using microbeam X-ray fluorescence (Micro-XRF) analyzer for determination of acid-resistant silicic particles in lung, and to explore its potential application in diagnosis of drowning.@*METHODS@#Thirty two white rabbits were divided randomly into drowning group (n=12), post-mortem immersion group (n=10) and control group (n=10). Lungs and water sample were collected for determination of area concentration of acid-resistant silicic particles using Micro-XRF method.@*RESULTS@#The area concentration of acid-resistant silicic particles for the drowning water sample was 4.4 mm2/mL. For the lungs of drowning group, the post-mortem immersion group and the control group, the determined average values were (25.30 +/- 10.95) mm2/g, (1.68 +/- 0.63) mm2/g and (1.65 +/- 0.85) mm2/g, respectively, with a statistically significant difference between the drowning group and the other two groups.@*CONCLUSION@#The area concentration of acid-resistant silicic particles in lungs may be used as an indicator of drowning. The method is highly sensitive and rapid. It provides a potential application in drowning diagnosis.

Corrosion behavior of laser and TIG welded austenitic stainless steel

The corrosion behaviour and the effect of microstructural changes of 304 austenitic stainless steel induced by the processes of gas tungsten arc welding [GTAW] or TIG and laser beam welding [LBW] have been investigated. For each experiment, base metal and heat affected zone [HAZ] have been selected. The microstructure and the phases present in the HAZ of the laser and TIG weld specimens were investigated and analyzed by optical microscopy, scanning electron microscopy and energy dispersive X-ray. Very fine grains were formed at the HAZ in comparison to the base metal carbide precipitations formed at the grain boundaries. Beside the main austenite phase a ferrite phase is present at the HAZ at the grain boundaries and inside the grain. The ferrite content was higher in laser weld zone than TIG weld zone. Electrochemical measurements using poteniodynamic cyclic polarization in 0.5M NaCI solution have been carried out for welded and unwelded specimens. The pitting potential was estimated reflecting higher pitting resistance for base metal than laser and TIG weld, respectively. The decrease in pitting resistance for laser and TIG weld could be related to the presence of carbide and ferrite phases in their microstructure

Evaluación de procedimientos de extracción de cinc presente en una zeolita activada / Evaluation of zinc extraction methods from activated zeolite

Los productos activos zeolíticos (PAZ) están enriquecidos con un catión que en nuestro caso determina su acción antimicrobiana. Se establecieron las condiciones para la extracción de este elemento, considerando las características intrínsecas de esta materia prima y sus formas terminadas tabletas y cremas. Se realizan diferentes tratamientos a las muestras optimizando las condiciones de trabajo. La determinación del contenido de cinc se realiza por fluorescencia de rayos X y espectrofotometría de absorción atómica. Se estableció el ataque triácido con H2SO4 HNO3 (2:3) y HCl como óptimo para el tratamiento de cremas y tabletas, mientras que el principio activo (PAZ) se trató con intercambio iónico

Determinación de elementos trazas en cataratas humanas mediante fluorescencia de rayos X por reflección total / Determination of the elements to trace in human waterfalls using the technique of fluorescence of X-rays in total reflection

La finalidad del presente trabajo de investigación fue desarollar una metodología experimental, utilizando la Técnica de Fluorescencia de Rayos-X en Reflexión Total, adaptada específicamente para el análisis multielemental en muestra de cataratas humanas. Se determinaron las concentraciones de 13 elementos trazas, en dos grupos de cataratas humanas- seniles y diabéticas- con peso atómico Z < 14. Los elementos detectados fueron:P,S,CI,K,Ca,Ti,Cr,Fe,Cu,Zn,Se,Br y Rb. De estos, Br,Cl y Rb mostraron diferencias estadísticamente significativas (p<0,005), al comparar las concentraciones de las cataratas diabéticas con aquellas relacionadas con la edad. La TXRF es un procedimiento con amplio potencial de aplicaciones prácticas, que abre nuevas líneas de investigación, particularmente en el análisis de muestras de fluidos y tejidos oculares