The study was conducted to develop a technique that measures the amount of gadolinium based contrast agent accumulated in a head tumour by x-ray fluorescence, while a patient is exposed to neutrons or during external beam radiotherapy planning. In this research, measurements of the gadolinium concentration in a vessel simulating a brain tumour located inside a head phantom, by the x-ray fluorescence method were taken, where the Magnevist contrast medium which has gadolinium atom, in the tumour vessel, was excited by a 36 GBq (0.97 Ci) 241Am source that emits gamma rays of 59.54 keV, in 35.7 % of it’s decays, resulting the emission of characteristic fluorescence of gadolinium at 42.98 keV that appeared in the X-ray fluorescence spectrum. A Cadmium Telluride (CdTe) detector was used to evaluate and make an analysis of the gadolinium concentration. Determinations of the gadolinium content were obtained directly from the detector measurements of XRF from gadolinium in the exposed tumour vessel. The intensity measured by the detector was proportional to the gadolinium concentration in the tumour vessel. These concentrations of gadolinium were evaluated for dose assessment. The positioning of the head phantom was selected to be in the lateral and vertex positions for different sizes of tumour vessels. Spherical tumour vessels of 1.0, 2.0, 3.0 cm and an oval tumour vessel of 2.0 cm diameter and 4.0 cm length, containing the gadolinium agent, contained concentration between 5.62 to 78.63 mg/ml. They were placed at different depths inside a head phantom at different positions in front of the detector and the source for the measurements. These depths ranged from 0.5 cm to 5.5 cm between the center of the tumour and interior wall of the head phantom surface. The total number of measurements in all four sizes of the tumour vessel was 478; 78 examinations of a 1.0 cm spherical tumour vessel, 110 examinations of a 2.0 cm spherical tumour vessel, 150 examinations of a 3.0 cm spherical tumour vessel and 140 examinations of a 2.0 x 4.0 cm ellipsoid tumour vessel. To measure the size and the shape of the tumour by the alternative radiographic method, a general x-ray machine with radiograph film was used. Based on that, the appropriate shape of concentration could be selected for therapy. The differences of optical density in the x-ray films showed that the noise was increased with low concentration of the Gd. Because radiographic film may be subjected to different chemical processes where the darkness will be affected, these measurements would be very hard to be quantitative. Accordingly it is difficult to use the film for Gd concentrations. The obtained data show that the method works very well for such measurements.

The study was conducted to develop a technique that measures the amount of gadolinium based contrast agent accumulated in a head tumour by x-ray fluorescence, while a patient is exposed to neutrons or during external beam radiotherapy planning. In this research, measurements of the gadolinium concentration in a vessel simulating a brain tumour located inside a head phantom, by the x-ray fluorescence method were taken, where the Magnevist contrast medium which has gadolinium atom, in the tumour vessel, was excited by a 36 GBq (0.97 Ci) 241Am source that emits gamma rays of 59.54 keV, in 35.7 % of it’s decays, resulting the emission of characteristic fluorescence of gadolinium at 42.98 keV that appeared in the X-ray fluorescence spectrum. A Cadmium Telluride (CdTe) detector was used to evaluate and make an analysis of the gadolinium concentration. Determinations of the gadolinium content were obtained directly from the detector measurements of XRF from gadolinium in the exposed tumour vessel. The intensity measured by the detector was proportional to the gadolinium concentration in the tumour vessel. These concentrations of gadolinium were evaluated for dose assessment. The positioning of the head phantom was selected to be in the lateral and vertex positions for different sizes of tumour vessels. Spherical tumour vessels of 1.0, 2.0, 3.0 cm and an oval tumour vessel of 2.0 cm diameter and 4.0 cm length, containing the gadolinium agent, contained concentration between 5.62 to 78.63 mg/ml. They were placed at different depths inside a head phantom at different positions in front of the detector and the source for the measurements. These depths ranged from 0.5 cm to 5.5 cm between the center of the tumour and interior wall of the head phantom surface. The total number of measurements in all four sizes of the tumour vessel was 478; 78 examinations of a 1.0 cm spherical tumour vessel, 110 examinations of a 2.0 cm spherical tumour vessel, 150 examinations of a 3.0 cm spherical tumour vessel and 140 examinations of a 2.0 x 4.0 cm ellipsoid tumour vessel. To measure the size and the shape of the tumour by the alternative radiographic method, a general x-ray machine with radiograph film was used. Based on that, the appropriate shape of concentration could be selected for therapy. The differences of optical density in the x-ray films showed that the noise was increased with low concentration of the Gd. Because radiographic film may be subjected to different chemical processes where the darkness will be affected, these measurements would be very hard to be quantitative. Accordingly it is difficult to use the film for Gd concentrations. The obtained data show that the method works very well for such measurements.

David Richard Walker’s Metrology of the Roman Silver Coinage analyzed the silver content of over 5000 Roman denarii, antoniniani, and drachmae using x-ray fluorescence (XRF) spectrometry. His results have been widely cited and used by scholars in the fields of Roman economic theory and numismatics. This thesis seeks to prove that Walker’s XRF results were not only inaccurate, but inconsistently so. Corrosion and surface enrichment on silver-copper coins have caused surface-level elemental examinations, like XRF, to produce incorrect results. The results from Walker’s XRF analysis have been compared against results from four individual wet chemical studies. The comparisons display striking, and significant, differences. I am forced to conclude that Walker’s data does not in any way align with the true silver content of the coins he analyzed. As a result, this thesis will re-examine several theories and hypotheses posed by scholars who used Walker’s data and propose new, more appropriate, uses for Walker and XRF analysis outside of the examination of corroded silver-copper coins.

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Made available in DSpace on 2014-10-09T12:49:45Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:07Z (GMT). No. of bitstreams: 1 10282.pdf: 3788200 bytes, checksum: 89ccf6d2ea9e26c2736dc1bbebcde360 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEn-CNEN/SP

Made available in DSpace on 2014-10-09T12:49:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:47Z (GMT). No. of bitstreams: 0 / Neste trabalho é descrito um procedimento para a determinação quantitativa da espessura e composição química de filmes finos, por fluorescência de raios X por dispersão de comprimento de onda (WDXRFS), utilizando-se o método de Parâmetros Fundamentais (FP). Este método foi validado dentro dos padrões de garantia de qualidade e aplicado as amostras de Al, Cr, TiO2, Ni, ZrO2 (monocamada) e Ni/Cr (duplacamada) sobre vidro; Ni sobre aço inoxidável e zinco metálico e TiO2 sobre ferro metálico (monocamada), as quais foram preparadas por deposição física de vapor (PVD). Os resultados das espessuras foram comparados com os métodos de Absorção (FRX-A) e Retroespalhamento de Rutherford (RBS), demonstrando a eficiência do método de parâmetros fundamentais. As características estruturais das amostras foram analisadas por difração de raios X (DRX) e mostraram que os mesmos não influenciam nas determinações das espessuras. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Orientador: Silvana Moreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T05:19:51Z (GMT). No. of bitstreams: 1 Geraldo_SimoniMicheti_M.pdf: 8576780 bytes, checksum: 143842c5f48e40fb90b5def8331f572b (MD5) Previous issue date: 2011 / Resumo: Os metais podem ser introduzidos no ambiente naturalmente pelo intemperismo dos minerais e por fontes não naturais como fertilizantes, pesticidas, combustão de carvão e óleo, emissões veiculares, mineração, fundição, refinamento e incineração de resíduos urbanos e industriais. Atualmente muitos estudos utilizam os bioindicadores, plantas ou animais capazes de apresentar respostas qualitativas e/ou quantitativas, quando expostas a substâncias poluentes. As árvores registram e incorporam no seu lenho, desenvolvido ano após ano, as impressões do meio abiótico, tornando possível o estudo das diferentes alterações ambientais, entre elas a poluição, ocorridas ao longo da vida dessas árvores. A possibilidade de datação dos anéis de crescimento do lenho das árvores, aliada à aplicação das informações registradas em sua estrutura para estudos ambientais e históricos deu início à ciência chamada de dendrocronologia. A espécie selecionada para o estudo foi a Tipuana tipu. O presente trabalho teve como objetivo principal a determinação do teor de metais tóxicos em amostras de anéis de crescimento de árvores da espécie Tipuana tipu, previamente datados, coletadas nas regiões da Lapa, Pompéia, Sumaré, Butantã na cidade de São Paulo, através da técnica de Fluorescência de Raios X por Reflexão Total com Radiação Síncrotron. Foram realizadas coletas de anéis também no Campus da ESALQ/USP em Piracicaba (SP), local de pouco acesso e com baixo fluxo de veículos. Foram encontrados os seguintes elementos: K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Ba e Pb. Alguns elementos traços apresentaram concentrações acima das consideradas normais em determinados períodos. Na cidade de São Paulo, a amostra 2 do Campus do IPT no Butantã foi a que apresentou maior toxicidade, com concentrações acima do limite tolerável para os seguintes elementos: Ti, Cr, Fe, Cu, Zn, Rb, Sr e Pb. Para as amostras coletadas no Campus da ESALQ em Piracicaba, a amostra 2 apresentou concentrações mais elevadas para a maioria dos elementos quando comparada as outras quatro amostras coletadas no mesmo local, ultrapassando os limites de toxicidade para: Cr, Fe, Ni, Cu, Zn, Sr e Pb. Pelos resultados obtidos podemos considerar que os anéis de árvore de crescimento da espécie Tipuana tipu podem ser utilizados como bioindicadores da contaminação ambiental / Abstract: Metals can be introduced in the environment naturally by the weathering of the minerals and by no natural sources as fertilizers, pesticides, oil and coal combustions, vehicular emissions, mining, foundry, refinement and incineration of urban and industrial wastes. Nowadays many studies use the bio-indicators, plants or animals capable to present qualitative and/or quantitative answers, when exposed to substances pollutant. Trees record and incorporate in their log, developed year after year, the impressions of the environment, becoming possible the study of the different environmental changes, including contamination, that have occurred over the life of these trees. The possibility to date the growth rings, combining with the information recorded in its structure to environmental and historical studies began to science called dendrochronology. The selected species, Tipuana tipu, of the Leguminosae family, is native of Argentina and Bolivia and was introduced in Brazil as ornamental. It is one of the most common trees in urban landscaping in Sao Paulo city. The present project has as main objective the determination of the content of heavy metals in samples of growth tree rings of Tipuana tipu, previously dated, collected in strategically locations of São Paulo, using Total Reflection X-Ray Fluorescence with Synchrotron Radiation (SR-TXRF). Samples were collected also in the Campus of ESALQ/USP, in Piracicaba (SP), local of little access and small flow traffic. The following elements were determined: K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Ba, Pb. Some trace elements present concentrations higher than considered as normal in some periods. In São Paulo city, sample 2 collected in IPT Campus, Butantã, showed the highest toxicity, with concentration above the tolerable limit for the elements: Ti, Cr, Fe, Cu, Zn, Rb, Sr and Pb. For the samples collected in the ESALQ Campus, Piracicaba city, the sample 2 present highest concentrations for the majority of the elements when compared to the others four samples collected at the same place, exceeding the toxicity limits for: Cr, Fe, Ni, Cu, Zn, Sr and Pb. By the results obtained we can considerate that growth tree rings of Tipuana tipu specie can be used as bioindicators of environmental contamination / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil

<p><b><i>Background and Objective:</i></b> Pb is a well-known toxic metal that can accumulate in bones over time and still threatening large populations nowadays, even those who are environmentally exposed to it. Strontium (Sr) is a metal directly related to bone health and has been used in the treatment of osteoporosis disease as a supplement. Manganese (Mn) is an essential nutrient in the body, yet excessive Mn is toxic and affecting many organ systems. Another toxic metal, mercury (Hg), has been poising different populations primarily through seafood consumptions, especially inducing neurological disorders in infants and fetuses. Even though significant associations between the above metal exposures and health outcomes have been recognized over the decades, the current technologies are limited in assessing cumulative long-term exposures <i>in vivo</i> to evaluate such associations further. Bone and toenail are appropriate biomarkers to reflect long-term exposure due to the longer half-life of these metals in them than in the traditional biomarkers. Therefore, this work evaluated the usefulness of portable x-ray fluorescence (XRF) technology on <i>in vivo</i> quantification of Pb and Sr in bone, and Mn and Hg in toenail.</p> <p><b><i>Materials and Methods:</i></b> The portable XRF device was calibrated by using the Pb- and Sr-doped bone-equivalent phantoms, and Mn- and Hg-doped nail-equivalent phantoms, correspondingly in different projects. Seventy-six adults (38-95 years of age, 63 ± 11 years) from Indiana, USA, were recruited to participate in this study. For the <i>in vivo</i> bone measurements, each participant was measured at the mid-tibia bone using the portable XRF and K-shell XRF system (KXRF). We estimated the correlation between the bone Pb concentration measured by both devices to evaluate the use of the portable XRF in the bones. Using the portable XRF, the bone Sr exposure of the study population were simultaneously assessed with the bone Pb exposures. Besides, we analyzed the mid-tibia bone Sr data of a Chinese population, which were measured with the same portable XRF device by our research group. We also examined the extent to which the detection limit (DL) of the portable XRF was influenced by scan time and overlying soft tissue thickness for both Pb and Sr. </p> <p>For the exposure assessment of Mn and Hg in toenails, we first established system calibrations and determined the DL with phantoms. In order to validate the portable XRF in a population study, the recruited participants were measured at the big toenail by the device, and their toenail clippings were analyzed by the inductively coupled plasma spectrometry (ICP-MS). Besides, we analyzed the toenail data of an occupationally-exposed population, collected by our collaborators in Boston. A portable XRF device with the same model as ours was used in that study. </p> <p><b><i>Results:</i></b> The uncertainty of <i>in vivo</i> individual bone measurement increased with higher soft tissue thickness overlying bone, and reduced with extending measurement time. With thickness ranging from 2 to 6 mm, the uncertainty of a 3-minute <i>in vivo</i> measurement ranged from 1.8 to 6.3 ug/g (ppm) for bone Pb and from 1.3 to 2.3 ppm for bone Sr. Bone Pb measurements via portable XRF and KXRF were highly correlated: R=0.48 for all participants, and R=0.73 among participants with soft tissue thickness < 6 mm (72% of the sample). A trend of different bone Sr concentrations was observed across the races and sexes. </p> <p>The DL of the portable XRF with 3-minute toenail measurements was 3.59 ppm for Mn and 0.58 ppm for Hg. The portable XRF and ICP-MS measurements were highly correlated in the occupational populations for both Mn (R = 0.59) and Hg (R = 0.75). A positive correlation (R = 0.34) was found for toenail Mn measurements in the environmentally-exposed population, while a non-significant correlation was observed for toenail Hg due to the extremely low-level of Hg (Mean = 0.1 ppm) in the study population. </p> <p><b><i>Discussion and Conclusion:</i></b> The portable XRF could be a valuable tool for non-invasive <i>in vivo</i> quantification of bone Pb and Sr, especially for people with thinner soft tissue; and of toenail Mn and Hg, especially for people with moderate- to high-level exposures. </p>

Iron overload conditions are a prevalent issue in global healthcare that require the accurate monitoring of iron levels to effectively provide treatment. X-ray fluorescence has emerged as a candidate for a point-of-care measurement tool for the detection of trace elements in vivo. This study explores the feasibility of a portable in vivo x-ray fluorescence (IVXRF) instrument using 125I as a point-of-care device in measuring skin iron levels. The system was calibrated using iron-doped water phantoms for various physiologically-applicable iron concentrations. Measurements were conducted on ex vivo rat skin samples (n = 34), which were then compared to a benchmark laboratory-based XRF system. Monte Carlo modelling using MCNP 6.2 was used to simulate the system in different conditions and provide an estimate of the radiation dose of the system on soft tissue. The R2 value for the calibration line of iron concentration in ppm to normalized iron signal was determined to be 0.985 (p < 0.01). For a measurement period of 1800 s real-time, the minimum detectable limit (MDL) of the system is 3.86 ± 0.06 ppm of iron. The R2 value for the linear regression between the IVXRF and benchmark XRF system normalized iron signals was 0.731 (p < 0.01). The R2 value for the linear regression between the IVXRF normalized iron signal and sample injected iron dose was 0.719 (p < 0.01), meaning the system can distinguish between different iron levels in rat skin. From the Monte Carlo simulations, the expected effective dose contribution from the IVXRF system is 101.68 ± 0.03 nSv. The IVXRF system was shown to accurately measure iron concentrations in ex vivo rat skin samples within the iron concentration ranges found within healthy and iron-overloaded patients. Further work shall be conducted to validate the system in in vivo applications. / Thesis / Master of Science (MSc) / Iron overload is a prevalent issue in healthcare, with many individuals experiencing detrimental symptoms, such as organ damage and heart failure. Modern treatment significantly improves quality of life but must be continuously monitored. This thesis covers the development of a non-invasive, cost-effective, and accurate system that can measure skin iron levels in patients to ensure effective monitoring. The results from this thesis suggest that the system can be used for clinical use to measure patient skin iron levels. It can theoretically measure iron in patients with normal and elevated iron levels. Simulation work suggests that the system will lead to negligible risk from radiation exposure. While this thesis and its findings support the feasibility of the system, further work is required before clinical implementation of the device.