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1
Samei, Ehsan. "Theoretical study of various thermoluminescent dosimeters heating schemes." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/16481.
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Prause, Christopher Alvin. "External detection and measurement of inhaled radionuclides using thermoluminescent dosimeters." Texas A&M University, 2006. http://hdl.handle.net/1969.1/5021.
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Many radiation detection programs use bio-assays, whole-body counters, or air
sampling to estimate internal doses. This study examines the possibility of using a
common external thermoluminescent dosimeter (TLD) badge as a device for detecting
inhaled radionuclides through radiation those radionuclides emit which escape the body.
The three common radionuclides chosen for modeling due to their varying decay modes
and use or production in the nuclear industry were Cs-137, U-238, and Sr-90. These three
radionuclides were modeled for biological and radiological removal in the dynamic
systems modeling program of STELLA II and modeled for TLD dose per organ in the
geometry and radiation simulation program of MCNP.
The results show that none of the nuclides in the study can be detected at air
concentrations below regulatory limits for acute inhalation exposures. To achieve a
detectable dose from an 8-hour work exposure, with a 90-day wait until the TLD is read,
the airborne concentrations for the inhalation classes that produced the most dose per Bq
would be 37.9 kBq/m3, 146 MBq/m3, and 1.67 MBq/m3 for Cs-137, U-238, and Sr-90,
respectively.
3
Bhengu, Khumbulani John. "The use of thermoluminescent dosimeters for In-vivo dosimetry in a fast neutron therapy beam." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/2799.
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Bibliography: leaves 72-77.Thermoluminescent detectors (TLD-700) have been investigated for absorbed dose measurements in a p(66)/Be neutron therapy beam at the National Accelerator Centre. Chips were selected based on their reproducibility and chip individual neutron calibration factors were derived. The dose non-linearity was determined in peak 5 and peak 6 and dose non-linearity corrections were performed. The sensitivity of TLD-700 chips with depth and off-axis distance was determined. In-vivo dose measurements were performed on seven patients (9 fields). In the entrance in-vivo dose measurements, a maximal deviation of 3.2 % was detected and a systematic difference of 1.7 % was observed. On the exit side, a maximal deviation of -7.3 % was detected and a systematic difference of -5.1 % was observed. The glow curve peak 6/5 ratio was investigated and found to correlate with the qualitative variations of the average LET in the neutron beam.
4
BRAVIM, AMANDA. "Aplicação das técnicas de dosimetria termoluminescente (TL) e luminescência opticamente estimulada (OSL) na determinação de curvas de isodose em uma simulação de tratamento de câncer pela técnica de radioterapia em arco modulado volumétrico – VMAT." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23906.
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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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FUKUMORI, DAVID T. "Desenvolvimento e estudo de materiais termoluminescentes baseados em óxido de alumínio para aplicação em dosimetria." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9931.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
6
Quinn, Bruce David 1955. "Dose rate measurements in the cobalt-60 gamma irradiation facility using thermoluminescent dosimeters." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277923.
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A dose rate measurement survey was performed at various locations inside the radiation chamber of the Cobalt-60 gamma irradiation facility located in Room 130, Building 20 at the University of Arizona. TLDs were used for the dose rate measurements. It was observed that the dose rates decrease rapidly with increasing distance from the source. Also, dose rates decreased with increased distance away from the centerline of the radiation chamber which is indicative of the position of the effective center of the source. Percent dose rates with respect to the dose rate of the calibration position were tabulated.
7
Aschan, Carita. "Applicability of thermoluminescent dosimeters in X-ray organ dose determination and in the dosimetry of systemic and boron neutron capture radiotherapy." Helsinki : University of Helsinki, 1999. http://ethesis.helsinki.fi/julkaisut/mat/fysii/vk/aschan/.
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MOURA, EDUARDO S. de. "Estudo e levantamentos de parametros para dosimetria de fontes de Iodo-125 aplicadas em braquiterapia." reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9624.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
9
Bravim, Amanda. "Avaliação de dosímetros termoluminescentes empregando objetos simuladores equivalentes à água para aplicação na dosimetria de feixes clínicos de elétrons." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-20062011-101414/.
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A dosimetria em Radioterapia prevê a calibração do feixe de radiação e a dosimetria de rotina para controle de qualidade, pois o seu principal objetivo é determinar, com maior precisão, a dose absorvida pelo tumor. Este trabalho tem como objetivo avaliar o comportamento de três dosímetros termoluminescentes na dosimetria de feixes clínicos de elétrons. O desempenho de detectores de sulfato de cálcio dopado com disprósio (CaSO4:Dy) produzidos pelo IPEN foi comparado com o de dois dosímetros comercialmente disponíveis pela Harshaw, ambos denominados TLD-100, porém com dimensões distintas. Os dosímetros foram caracterizados com a utilização de objetos simuladores de água, água sólida RMI-457 e PMMA em campos de radiação de elétrons de 4, 6, 9, 12 e 16 MeV. Também foram realizadas medidas em feixes de fótons de 6 e 15 MV (2 e 5 MeV) apenas para comparação de resultados. As curvas de dose-resposta foram obtidas para a radiação gama do 60Co no ar e em condições de equilíbrio eletrônico e para feixes clínicos de fótons e elétrons nas profundidades de máxima dose. A sensibilidade, a reprodutibilidade, a eficiência intrínseca e a dependência energética dos dosímetros termoluminescentes foram estudadas. O CaSO4:Dy apresentou comportamento semelhante ao dos TLD-100 com uma vantagem em relação à sensibilidade para os feixes e doses de radiação estudados. Sendo assim, o dosímetro produzido pelo IPEN pode ser considerado uma nova alternativa para a dosimetria nos departamentos de Radioterapia.The dosimetry in Radiotherapy provides the calibration of the radiation beam as well as the quality control of the dose in the clinical routine. Its main objective is to determine with greater accuracy the dose absorbed by the tumor. This study aimed to evaluate the behavior of three thermoluminescent dosimeters for the clinical electron beam dosimetry. The performance of the calcium sulfate detector doped with dysprosium (CaSO4: Dy) produced by IPEN was compared with two dosimeters commercially available by Harshaw. Both are named TLD-100, however they differ in their dimensions. The dosimeters were evaluated using water, solid water (RMI-457) and PMMA phantoms in different exposure fields for 4, 6, 9, 12 and 16 MeV electron beam energies. It was also performed measurements in photon beams of 6 and 15 MV (2 and 5 MeV) only for comparison. The dose-response curves were obtained for the 60Co gamma radiation in air and under conditions of electronic equilibrium, both for clinical beam of photons and electrons in maximum dose depths. The sensitivity, reproducibility, intrinsic efficiency and energy dependence response of dosimeters were studied. The CaSO4: Dy showed the same behavior of TLD-100, demonstrating only an advantage in the sensitivity to the beams and radiation doses studied. Thus, the dosimeter produced by IPEN can be considered a new alternative for dosimetry in Radiotherapy departments.
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SOUTO, EDUARDO de B. "Projeto, construção e caracterização de um dosímetro para radiação de nêutrons." reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11540.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Souto, Eduardo de Brito. "Projeto, construção e caracterização de um dosímetro para radiação de nêutrons." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-29032012-135436/.
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Com o objetivo de monitorar o crescente número de trabalhadores potencialmente expostos à radiação de nêutrons, foi projetado e desenvolvido um dosímetro individual para campos mistos nêutron-gama. O dosímetro proposto foi caracterizado para o espectro de energia de uma fonte de Amerício-Berílio e para o intervalo de dose de interesse da proteção radiológica (até 20 mSv). Para tanto utilizou-se a dosimetria termoluminescente de albedo e a dosimetria de traços nucleares, técnicas consagradas na literatura internacional, empregando materiais de fabricação nacional e de baixo custo. Um policarbonato comercial, denominado SS-1, foi caracterizado para aplicação como detector sólido de traços nucleares. Os parâmetros para revelação química e ampliação dos traços, assim como a metodologia de avaliação dos detectores foram determinados. Estudou-se a resposta dos detectores TLD-600, TLD-700 e SS-1 em campos mistos nêutrongama de uma fonte de Amerício-Berílio e definiu-se um algoritmo para cálculo da dose de nêutrons e de radiação gama. A razão entre as respostas para nêutrons térmicos, de albedo e rápidos permite analisar o espectro ao qual o dosímetro foi submetido e corrigir a resposta do detector de traços para variações no ângulo de incidência da radiação. O novo dosímetro está pronto e apresenta desempenho para ser usado como dosímetro de nêutrons no Brasil.An individual dosimeter for neutron-gamma mixed field dosimetry was design and developed aiming monitoring the increasing number of workers potentially exposed to neutrons. The proposed dosimeter was characterized to an Americium-Beryllium source spectrum and dose range of radiation protection interest (up to 20 mSv). Thermoluminescent albedo dosimetry and nuclear tracks dosimetry, traditional techniques found in the international literature, with materials of low cost and national production, were used. A commercial polycarbonate, named SS-1, was characterized for solid state tack detector application. The chemical etching parameters and the methodology of detectors evaluation were determined. The response of TLD-600, TLD-700 and SS-1 were studied and algorithms for dose calculation of neutron and gamma radiation of Americium- Beryllium sources were proposed. The ratio between thermal, albedo and fast neutrons responses, allows analyzing the spectrum to which the dosimeter was submitted and correcting the track detector response to variations in the radiation incidence angle. The new dosimeter is fully characterized, having sufficient performance to be applied as neutron dosimeter in Brazil.
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MATSUSHIMA, LUCIANA C. "Determinação das curvas de isodose e confirmação do planejamento em Radioterapia de Intensidade Modulada - IMRT convencional empregando as técnicas de termoluminescência, luminescência opticamente estimulada e detectores semicondutores." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23694.
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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
13
Mirzadeh, Kousha. "TLD Measurements on Patients being treated with a Taylor Spatial Frame : Using Radiation from Na18F PET/CT Studies and from Naturally Occurring Radioisotopes." Thesis, Stockholms universitet, Fysikum, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-109361.
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Background: In an ongoing study conducted at Karolinska Institutet & Karolinska University Hospital, Positron Emission Tomography (PET)/Computed Tomography (CT) scans are performed on patients with tibia fractures and deformations treated with Taylor Spatial Frames (TSFs) in order to monitor their bone remodeling progress. Each patients receive an administration of approximately 2 MBq/kg bodyweight of Na18F associated with PET scans on two sessions, six and twelve weeks after the attachment of the TSF. These PET/CT scans provide information about the progress of the healing bone and can be used to estimate the optimal time point for de-attachment of the TSF. The Standardized Uptake Value (SUV) is used as a measure of the rate of bone remodeling for these patients, however, there is a need for verification of this practice by a method independent of the PET scanner. Furthermore, information regarding the biodistribution of the Na18F throughout the body of these patients and the effects of the TSF on the CT scan X‑rays is required. Additionally, an investigation of alternative methods that have the potential to provide similar information with a lower absorbed dose to the patients is desirable. Materials and methods: Thermoluminescent Dosimeters (TLDs) were attached on the skin at the position of the heart, urinary bladder, femurs, fracture, and the contralateral tibia of twelve patients during the first one hour and five minutes after the administration of the Na18F. Additional TLD measurements were performed during the CT scan of two of these patients. From the PET scan images, SUVs at the fracture site of these patients were collected. An investigation of the possibility of exploiting the “naturally” occurring bone seeking radionuclide Strontium-90 (90Sr) in the human body to gain information about the fracture site was undertaken. Using a 90Sr source, three different detection techniques were evaluated and a practical methodology for in vivo measurements on the tibia fracture patients was developed. As it was concluded that TLD based measurements were the most suitable technique for this purpose, and it was tested on five patients with tibia fractures. Results: From the collected TLD data, it was concluded that for these patients the urinary bladder is the organ receiving the greatest amount of absorbed dose and the organ most affected as the administered activity exceeds 2 MBq/kg. On average, a three times higher surface dose was measured on the tibia fracture compared to the un-fractured tibia. A linear relationship between the surface dose and SUVmax was shown. A strong positive correlation between the activity concentration at the fracture site and the amount of injected activity was found, and it was demonstrated that this also affects the SUVs. For patients who were administered different amounts of Na18F for the two PET scans, maximum activity concentrationwas less affected than mean activity concentration. It was concluded that TSF’s effect on the scatter of the X-rays to organs higher up in the body is negligible. Regarding “naturally” occurring 90Sr in the human body, no higher activity at the fractured tibia compared to the non‑fractured tibia could be found. Conclusions: This project assessed the accumulation of Na18F in the fracture site of patients treated with TSF by a method independent of the PET scanner. The methodology of using SUVs as an indicator for bone remodeling was verified. It was shown that the uptake of Na18F by the fracture site is strongly correlated to the amount of injected activity. The importance of considering the amount of injected activity when evaluating and comparing SUVs was highlighted. In vivo measurements using LiF:Mn TLDs did not indicate any quantifiable higher concentration of 90Sr at the fracture in the tibia bone.
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Almeida, Shirlane Barbosa de. "Validação e avaliação dosimétrica empregando as técnicas de TL e OSL de materiais termoluminescentes para aplicação na dosimetria de feixes clínicos de elétrons utilizados na irradiação total da pele - TSI." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-08062017-153258/.
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A dosimetria in vivo têm se tornado um papel importante para o tratamento da irradiação total da pele dentro de um rigoroso programa de garantia de qualidade que deve ser parte integrante nos departamentos radioterápicos. A dosimetria em TSI é difícil, devido à complexidade do tratamento em avaliar a uniformidade da dose e medir a dose absorvida em profundidades rasas em toda extensão da superfície cutânea, tendo como consequência uma ampla variação na distribuição da dose. Os TLDs tem provado ser muito úteis para a distribuição e verificação da dose prescrita para o paciente, pois a dose pode diferir de local para local devido a geometria do corpo do paciente, sobreposições de estruturas e assimetrias do campo de radiação. A utilização de TLDs in vivo pode identificar variações da dose prescrita por apresentarem uma grande exatidão e precisão nas medidas. Nos setores de radioterapia vêm sendo empregado vários tipos de dosímetros, os mais utilizados são o Flureto de Lítio (TLD-100), onde obtém uma longa história neste tipo de aplicação. Novos materiais dosímetricos vêm ganhado grande importância na aplicação da dosímetria de feixes clínicos de elétrons, como o Sulfato de Cálcio dopado com Disprósio (TL) e o Óxido de Alumínio dopado com Carbono (OSL), este trabalho avalia o desempenho dosímetrico dos respectivos dosímetros termoluminescentes e a luminescência opticamente estimulada na aplicação da dosímetria de feixes clínicos de elétrons utilizados na irradiação total da pele.In vivo dosimetry has become an important role for the treatment of total skin irradiation within a rigorous quality assurance program that should be an integral part of the radiotherapy departments. TSI dosimetry is difficult because of the complexity of the treatment in assessing dose uniformity and measuring the dose absorbed at shallow depths throughout the skin surface extent, resulting in a wide variation in dose distribution. The TLDs have proven to be very useful for the distribution and verification of the dose prescribed for the patient as the dose may differ from place to place due to patient body geometry, overlapping of structures and asymmetries of the radiation field. The use of TLDs in vivo can identify variations in the prescribed dose because its measurement accuracy and great precision. Several types of dosimeters have been used in the radiotherapy sectors, the most commonly used are Lithium Fluride (TLD-100), where it obtains a long history in this type of application. New dosimetric materials have gained great importance in the dosimetry of clinical electron beams, such as Dysprosium-doped Calcium Sulphate (TL) and Carbon doped (OSL) based Aluminum Oxide, This work evaluates the performance of the respective thermoluminescent dosimeters and the optically stimulated luminescence in the dosimetry of clinical electron beams used in total irradiation of the skin.
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Vũ, Bezin Jérémi. "Optimisation et validation des méthodes de calcul de dose à distance des faisceaux d’irradiation pour leur application dans les études épidémiologiques et cliniques en radiothérapie." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS246/document.
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La proportion de survivants à un cancer dans la population des pays développés augmente rapidement. Dans plus de la moitié des cas, la radiothérapie a été une composante de leur traitement. Les rayons ionisants alors administrés peuvent induire de graves conséquences à long terme, en particulier les cancers radio-induits et les maladies cardiovasculaires. Ces évènements sont dus non seulement aux fortes doses administrées au volume cible, mais également aux doses plus faibles, de quelques milligray à quelques gray, non souhaitées, mais inévitablement administrées dans le reste du corps du patient par la dose hors champ. L’évolution des techniques de planification du traitement et de l’informatique en médecine permettent aujourd’hui d’obtenir, systématiquement, l’évaluation précise des doses les plus fortes administrées au patient. Les doses faibles à intermédiaires administrées en dehors du faisceau de traitement, ne sont pour leur part, ni habituellement prises en compte, ni correctement évaluées par les systèmes actuels de planification du traitement. L’objectif de ce travail était de proposer des méthodes pour estimer le rayonnement hors champ des faisceaux de photons des accélérateurs de radiothérapie externe. L’utilisation d’une bibliothèque graphique nous a permis de réaliser une représentation géométrique 3D partielle des appareils de traitement et des sources photoniques responsables de la dose reçue par le patient. Nous avons déterminé l’intensité de ces sources en utilisant des mesures réalisées dans des champs simples. Le modèle ainsi calibré permettait de simuler la variation de l’intensité des sources en fonction de la taille du champ. Cette approche a permis de décrire avec succès la variation de la dose mesurée par TLD en fonction de la distance et de la taille du champ en dehors de champs carrés. Les écarts entres les doses calculées et celles mesurées étaient inférieurs à 10 %. Une application dans des conditions cliniques a été menée, l’écart était alors en moyenne de 25 %The number of cancer survivors in developed counties increases rapidly. Fifty percent of patients treated for cancer will receive radiation therapy as part of their treatment. Ionizing radiation may induce severe long term effects, including secondary cancers and cardio-vascular diseases. Long term effects are not only due to high doses delivered in target volumes, but also to lower doses, ranging from several milligrays to several grays, undesired, but inevitably delivered in the rest of the patient’s body outside the treatment beams. Improvements in treatment planning technics and the use of computers in medicine made it possible to systematically estimate, prior to treatment, the highest doses delivered to the patient’s body. However, lower doses delivered outside the treatment beams are neither taken into account nor evaluated by present treatment planning systems. The aim of our work was to establish methods to estimate radiation doses outside photon beams from accelerators used in external radiation therapy. A graphics library was used to render a partial 3D representation of the accelerator and the photon sources associated. The intensity of these sources was determined using measurements performed in simple geometry fields. The calibrated model was hence used to estimate the source intensity variation with respect to field size. Using this method, we were able to estimate the variations of the TLD measured doses with respect to distance and field size with a 10% average discrepancy between calculations and measurements for points outside the field. Also, when testing the model in a clinical setup, the average discrepancy increased to 25%
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CAMPOS, VICENTE de P. de. "Desenvolvimento e avaliação de um novo porta detector/filtro para monitoramento termoluminescente com CaSOsub(4):Dy/PTFE." reponame:Repositório Institucional do IPEN, 2005. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11370.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
17
Yusoff, Ahmad Lutfi. "Development of silica-based thermoluminescence dosimeters." Thesis, University of Exeter, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414262.
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SILVA, MARIA R. O. de O. da. "Influencia da microestrutura e composicao de alumina na termoluminescencia visando sua aplicacao em dosimetria." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10974.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
19
Hernandez, Pete Jevon. "Response comparison of an optically stimulated luminescent dosimeter, a direct-ion storage dosimeter, and a thermoluminescence dosimeter." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2979.
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Issa, Fatma Mabruk. "Doped optical fibres thermoluminescence dosimetry for brachytherapy." Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580336.
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In the various brachytherapy techniques the intent is to deliver as high a tumour dose as possible, limited only by surrounding normal tissue tolerance. The main feature of the techniques is very steep dose gradients, representing a potential limiting factor in accurate dose distribution measurements around sources. Dose distributions at distances less than 1 cm are therefore normally generated using either validated Monte Carlo (MC) simulations or standard dose calculation formalisms, for example that of AAPM TG 43, while dose measurements can only be performed at larger distances, normally greater than 1 cm from the outer dimensions of the source encapsulation Ge-doped silica fibres are a viable thermoluminescent dosimetry (TLD) system, providing good spatial resolution of approximately 120 urn, sensitive response to ionizing radiations, large dynamic dose range, good reproducibility and reusability, dose rate independence, minimal fading, resistance to water and low cost. Dosimetric characterisation of commercial Ge-doped silica fibres have been obtained by subjecting them to kilovoltage therapeutic x-ray radiation beams, verifying their use for brachytherapy sources; dose response, reproducibility and fading at 90 kVp and 300 kVp have been investigated. Central-axis depth doses have been obtained at the two accelerating potentials using different field size applicators, measurements being made using the fibres in both water and a GAMMEX RMr 4571 solid water phantom. Comparison has been made with central-axis depth doses, measured using a 0.6 cm3 graphite-walled ionisation chamber data and British Journal of Radiology Supplement 25 tabulated values (both in water). Ge-doped optical fibre dosimeters show good dosimetric response for low photon energies. These desirable characteristics support the use of these TL fibres as dosimeters for brachytherapy applications. Ge-doped optical fibre TL dosimeters have been used to measure the dose distribution around two Low Dose Rate (LDR) 125r seeds; model 6711, the new thinner model 9011 and a High Dose Rate (HDR) 192rr (MicroSelectron V2) source at proximal distances down to 1 mm, measured in a Perspex medium. The anisotropy has also been measured in Perspex, for distances from 10 to 100 mm from a LDR 1251 seed model 6711 centre, in 10 mm increments and at angles 10° to 90° in 10° increments from the seed central axis. Measured doses have been compared with calculations and treatment planning system (TPS) predicted doses for the same locations. Monte Carlo simulations were obtained using the EGSnrc \ DOSRZnrc codes and TPS predicted doses were obtained using the system VariSeed V8.0.2. For 1251 seed model 6711, the measurements agree with simulations to within 2.3 % ± 0.3 % along the transverse and perpendicular axes and within 3.0 % ± 0.5 % for measurements investigating anisotropy in angular dose distribution. Measured and Veriseed™ brachytherapy treatment planning system (TPS) values agreed to within 2.7 % ± 0.5 %. For the new thinner 1251 model 9011, dose measurements were in good agreement with simulations to within 2.1 ± 0.2 %, while dose measurements and doses obtained through use of the Variseed TPS agreed well, to within 2.2 ± 0.5 %. The above work has therefore demonstrated the applicability of Ge-doped optical fibres for use in brachytherapy.
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Larsen, Agersnap, Niels, and risoe@risoe dk. "Dosimetry based on thermally and optically stimulated luminescence." Thesis, Risoe National Laboratory, 1999. http://www.risoe.dk/rispubl/NUK/ris-r-1090.htm.
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Lontsi, Sob Aaron Joel. "Thermoluminescence of natural quartz." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013358.
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The kinetic and dosimetric features of the main thermoluminescence peak of quartz have been investigated in unannealed as well in quartz annealed at 500˚C for 10 minutes. The main peak is found at 92 and 86˚C respectively for aliquots of unannealed and annealed samples irradiated to 10 Gy and heated at 5.0˚C/s. For each sample, the intensity of the main peak is enhanced with repetitive measurement whereas its maximum temperature is unaffected. The peak position of the main peak in each sample is independent of the irradiation dose and this, together with its fading characteristics are consistent with first-order kinetics. For low doses, typically between 2 and 10 Gy, the dose response of the main peak in each sample is linear. In the intermediate dose range from 10 to 60 Gy, the growth of the main peak in each sample is sub-linear and for greater doses, in the range from 60 Gy to 151 Gy, it is linear again. The half-life of the main peak of the unannealed sample is about 1.3 h whereas that of the annealed sample is about 1.2 h. The main peak in each sample can be approximated to a first-order glow peak. As the heating rate increases, the intensity of the main peak in each sample decreases. This is evidence of thermal quenching. The main peak in each sample is the only peak regenerated by phototransfer. The resulting phototransferred peak occurs at the same temperature as the original peak and has similar kinetic and dosimetric features. For a preheat temperature of 120˚C, the intensity of the phototransferred peak in each sample increases with illumination time up to a maximum and decreases afterwards. At longer illumination times (such as 30 min up to 1 h), no further decrease in the intensity of the phototransferred peak is observed. The traps associated with the 325˚C peak are the main source of the electrons responsible for the regenerated peak. Radioluminescence emission spectra were also measured for quartz annealed at various temperatures. Emission bands in quartz are affected by annealing and irradiation. A strong enhancement of the 3.4 eV (~366 nm) emission band is observed in quartz annealed at 500˚C. A new emission band which grows with annealing up to 1000˚C is observed at 3.7 eV (~330 nm) for quartz annealed at 600˚C. An attempt has been made to correlate the changes in radioluminescence emission spectra due to annealing with the influence of annealing on luminescence lifetimes in quartz.
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GROSSI, FABIO H. "Caracterizacao e padronizacao de um sistema dosimetrico termoluminescente para radiacoes ultravioleta e laser utilizando o CaSO sub(4):Dy." reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10987.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:99/06632-0
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Alanazi, Abdulaziz. "A study of novel forms of thermoluminescent media for clinical dosimetry." Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/849664/.
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This work encompasses studies of two novel materials for radiation dosimetry as well establishment of a novel technique for dosimetry. Silica-based material and CNTs (carbon nanotubes) were used as passive radiation dosimeters. The atomic effective numbers (Zeff) for the silica-based materials (glass beads and optical fibres) are similar to that for the bone tissue, while carbon nanotubes have effective atomic number (Zeff) similar to that of human soft tissue. Present studies have been carried out seeking to improve upon the thermoluminescence (TL) yield of commercially produced small diameter telecommunication optical fibres as well as glass beads. Their small sizes make them of great interest as they can fulfil the Bragg–Gray cavity theory. In this thesis, demonstration is made of their utilities to measure the depth-dose profile for protons and neutrons at therapeutic energies range. In regard to carbon nanotubes, these were made in thin films (known as buckypaper) with various thickness ranging from ~10 to ~100 μm to fulfil two conditions; (i) satisfying the Bragg–Gray cavity theory, and; (ii) to present tissue equivalent material. The CNTs were examined in using conventional thermoluminescence technique. Then, a novel method of dosimetry was established by use of x-ray photoelectron spectroscopy (XPS).
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Karali, Turgay. "Luminescence studies of rare earth doped dosimeters." Thesis, University of Sussex, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298733.
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BRANCO, ISABELA S. L. "Estudo dos efeitos na dose devido à heterogeneidade em braquiterapia com fontes de I125." reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/28045.
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A braquiterapia de baixas taxas de dose realizada com sementes de 125I tem sido amplamente usada por décadas em variados sítios anatômicos, com bons resultados clínicos. O advento de algoritmos para cálculo de dose baseados em modelos (MBDCAs) permitiu aprimorar oestudo de deposição da dose considerando heterogeneidades como diferentes tecidos, órgãos,aplicadores com composições diferentes da água, proporcionando a análise em geometriascomplexas. As simulações matemáticas realizadas através destes algoritmos possibilitam odesenvolvimento de modelos fisicamente mais acurados que estendem sua aplicabilidade àverificação de sistemas de planejamento em braquiterapia. Neste trabalho foram estudadasconfigurações de objetos simuladores confeccionados para medidas experimentais e simuladosatravés do código MCNP de Monte Carlo a fim de observar as diferenças ocasionadas pelaintrodução de heterogeneidades quando presentes fontes de 125I de baixa taxa de dose. Para estepropósito, distintas as vertentes do tema foram abordadas, entre elas o estudo da influênciaexercida pelos parâmetros de densidade e composição dos materiais tecido equivalentes. Osresultados obtidos demonstraram que, o efeito que a composição de cada um dos materiaisexerce sobre a deposição de dose é mais expressivo que o efeito de sua densidade. Em outroestudo, foi estabelecida uma relação para estimar, de maneira simples, a dose de atenuação detecidos heterogêneos a partir da aferição ou simulação da dose obtida num objeto simuladorconstituído por PMMA, metodologia que pode ser desenvolvida e implementada na rotina clínica.Para complementação das análises dos estudos dosimétricos com a presença deheterogeneidades, foi realizada a validação da geometria simulada da semente de 125I, onde sereproduziu a metodologia de cálculo dosimétrico presente no TG-43 da AAPM. Além disto, foirealizado o estudo teórico da dependência energética dos dosímetros termoluminescentes paraanalisar a variação de sua resposta conforme a energia. A metodologia desenvolvida para oestudo dos efeitos da heterogeneidade na deposição de dose é recomendada na avaliação desistemas de planejamento computadorizados que possuem algoritmos de cálculo de dosebaseados em modelos, quando utilizadas fontes de 125I com baixa taxa de dose, de forma acontribuir na incorporação de novas estimativas de doses com maior acurácia.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Han, Seungjae. "Mixed field dosimetry using focused and unfocused laser heating of thermoluminescent materials." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/16854.
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NUNES, MAIRA G. "Avaliação do desempenho dos detectores termoluminescentes de CaSOsub(4):Dy e LiF:Mg, Ti na dosimetria de feixes clínicos de elétrons." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11657.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP
29
Woodman, Robert Harvey. "Development of magnesium tetraborate as a material for thermoluminescence dosimetry." Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/50096.
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Magnesium tetraborate is a candidate phosphor for a laser-heated thermoluminescence (TL) dosimetry system which is under development. Near tissue-equivalent radiation absorption properties and reported sensitivity to low radiation doses offer advantages over commonly employed LiF phosphors.
Sintered wafers suitable for routine measurement were prepared. The effects of powder preparation conditions and activator concentration on TL sensitivity were investigated. Samples with additional impurities (co-doped samples) were prepared in order to increase sensitivity through coactivation or sensitization effects. TL emission spectra were employed to evaluate the effects of co-doping.Master of Science
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Seneza, Cleophace. "Thermoluminescence of secondary glow peaks in carbon-doped aluminium oxide." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013053.
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Carbon-doped aluminium oxide, α-Al₂O₃ : C, is a highly sensitive luminescence dosimeter. The high sensitivity of α-Al₂O₃ : C has been attributed to large concentrations of oxygen vacancies, F and F⁺ centres, induced in the material during its preparation. The material is prepared in a highly reducing atmosphere in the presence of carbon. In the luminescence process, electrons are trapped in F-centre defects as a result of irradiation of the material. Thermal or optical release of trapped electrons leads to emission of light, thermoluminescence (TL) or optically stimulated light (OSL) respectively. The thermoluminescence technique is used to study point defects involved in luminescence of α-Al₂O₃ : C. A glow curve of α-Al₂O₃ : C, generally, shows three peaks; the main dosimetric peak of high intensity (peak II) and two other peaks of lower intensity called secondary glow peaks (peaks I and III). The overall aim of our work was to study the TL mechanisms responsible for secondary glow peaks in α-Al₂O₃ : C. The dynamics of charge movement between centres during the TL process was studied. The phototransferred thermoluminescence (PTTL) from secondary glow peaks was also studied. The kinetic analysis of TL from secondary peaks has shown that the activation energy of peak I is 0.7 eV and that of peak III, 1.2 eV. The frequency factor, the frequency at which an electron attempts to escape a trap, was found near the range of the Debye vibration frequency. Values of the activation energy are consistent within a variety of methods used. The two peaks follow first order kinetics as confirmed by the TM-Tstop method. A linear dependence of TL from peak I on dose is observed at various doses from 0.5 to 2.5 Gy. The peak position for peak I was also independent on dose, further confirmation that peak I is of first order kinetics. Peak I suffers from thermal fading with storage with a half-life of about 120 s. The dependence of TL intensity for peak I increased as a function of heating rate from 0.2 to 6ºCs⁻¹. In contrast to the TL intensity for peak I, the intensity of TL for peak III decreases with an increase of heating rate from 0.2 to 6ºCs⁻¹. This is evidence of thermal quenching for peak III. Parameters W = 1.48 ± 0:10 eV and C = 4 x 10¹³ of thermal quenching were calculated from peak III intensities at different heating rates. Thermal cleaning of peak III and the glow curve deconvolution methods confirmed that the main peak is actually overlapped by a small peak (labeled peak IIA). The kinetic analysis of peak IIA showed that it is of first order kinetics and that its activation energy is 1:0 eV. In addition, the peak IIA is affected by thermal quenching. Another secondary peak appears at 422ºC (peak IV). However, the kinetic analysis of TL from peak IV was not studied because its intensity is not well defined. A heating rate of 0.4ºCs⁻¹ was used after a dose of 3 Gy in kinetic analysis of peaks IIA and III. The study of the PTTL showed that peaks I and II were regenerated under PTTL but peak III was not. Various effects of the PTTL for peaks I and II for different preheating temperatures in different samples were observed. The effect of annealing at 900ºC for 15 minutes between measurements following each illumination time was studied. The effect of dose on secondary peaks was also studied in this work. The kinetic analysis of the PTTL intensity for peak I showed that its activation energy is 0.7 eV, consistent with the activation energy of the normal TL for peak I. The PTTL intensity from peak I fades rapidly with storage compared with the thermal fading from peak I of the normal TL. The PTTL intensity for peak I decreases as a function of heating rate. This decrease was attributed to thermal quenching. Thermal quenching was not observed in the case of the normal TL intensity. The cause of this contrast requires further study.
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MATSUSHIMA, LUCIANA C. "Avaliacao da resposta de detectores termoluminescentes na dosimetria de feixes clinicos utilizando diferentes objetos simuladores." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9562.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
32
Chen, Geng, and 陳耿. "Studies of quartz luminescence sensitivity relevant to dating and dosimetry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B42576143.
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Chen, Geng. "Studies of quartz luminescence sensitivity relevant to dating and dosimetry." Click to view the E-thesis via HKUTO, 2000. http://sunzi.lib.hku.hk/hkuto/record/B42576143.
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Wells, C. "The derivation of radiation flux parameters from thermoluminescent dosimetry measurements in mixed neutron/gamma ray fields." Thesis, University of Greenwich, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376564.
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Lhallabi, Abdessamad. "Evaluation des incertitudes dans la preparation et la realisation des traitements par radiotherapie transcutanee." Toulouse 3, 1987. http://www.theses.fr/1987TOU30076.
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Chen, Yongye. "Study of luminescence signals from quartz and their applications in geothermometry." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/b40203955.
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HABITZREUTER, ANGELA B. "Implementacao da irradiacao de corpo inteiro em radioterapia." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9578.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
38
Chen, Yongye, and 陳永曄. "Study of luminescence signals from quartz and their applications in geothermometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40203955.
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Hochman, Mark Brett McEwen. "The application of artificial thermoluminescence to uranium exploration and uranium ore genesis studies." Title page, abstract and contents only, 1989. http://web4.library.adelaide.edu.au/theses/09PH/09phh6825.pdf.
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França, Leonardo Vinícius da Silva. "Development of a Thermoluminescence - Radioluminescence Spectrometer." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-29052018-162229/.
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In this work, initially the radioluminescence (RL) and thermoluminescence (TL) techniques are presented. The radioluminescence is the prompt luminescence emitted by a material under ionizing radiation exposure. The thermoluminescence is the luminescence emitted by a material previously exposed to ionizing radiation when excited by heat. Enegy bands concepts, defects in crystals and the different processes of ionization that take place in matter when exposed to ionizing radiation are briefly discussed in order to present the mechanisms involved in RL and TL processes. The usage of the techniques in characterization of materials and dosimetry is reported, legitimating the importance of the instrument developed. Mechanical and structural parts as well as a description of each component of the instrument are fairly described. The implemented algorithm for controlling the instrument and acquiring data is also discussed. The development of the instrument enabled us to generate temperature ramps with a quite good performance, reaching temperatures up to 500 °C with deviations up to 2 °C, having used heating rates between 0.5 °C/s and 5 °C/s. Calibrations of optical spectrometer used in light collection and irradiation system were carried out. Lastly, TL and RL spectra tests were performed. The RL tests were carried out using several materials which emission spectra are well known by literature, namely, carbon-doped aluminium oxide Al2O3:C, terbium-doped gadolinium oxysulphide Gd2O2S:Tb, europium-doped yttrium oxide Y2O3:Eu and dysprosium-doped calcium borate CaB6O10:Dy. For the TL spectra test, the aluminium oxide doped with carbon Al2O3:C was used. The results of RL and TL spectra tests showed a good agreement with the literature, pointing out that the instrument developed in this work is comparable to others instruments in operation from others research groups, making our results reliable.Nesse trabalho, inicialmente as técnicas de radioluminescência (RL) e termolumi- nescência (TL) são apresentadas. A radioluminescência é a luminescência imediata emitida por um material quando exposto à radiaçao ionizante. A termoluminescência é a luminescência emitida por um material previamente exposto à radiação quando este é aquecido. Conceitos de bandas de energia, defeitos em cristais e os diferentes processos de ionização que ocorrem na matéria quando exposta à radiação ionizante são brevemente discutidos a fim de apresentar os mecanismos envolvidos na RL e TL. A utilização das técnicas na caracterização de materiais e na dosimetria é reportada, justificando a importância do instrumento desenvolvido. As partes mecânicas/estruturais e uma descrição de cada componente do instrumento são descritos. O algoritmo implementado para controle do instrumento e aquisição de dados é também descrito. O desenvolvimento do instrumento possibilitou a geração de rampas de temperatura com uma boa performance, atingindo até 500 °C com variações de até 2 °C ao utilizar taxas de aquecimento entre 0.5 °C/s e 5 °C/s. Calibrações do espectrômetro óptico utilizado na aquisição da luminescência e do sistema de irradiação foram executadas. Por fim, testes de aquisição de espectros de RL e TL foram realizados. Os testes de RL foram realizados utilizando vários materiais cujos espectros de emissão são bem conhecidos pela literatura, a saber, óxido de alumínio dopado com carbono Al2O3:C , oxisulfeto de gadolínio dopado com térbio Gd2O2S:Tb , óxido de ítrio dopado com európio Y2O3:Eu e borato de cálcio dopado com disprósio CaB6O10:Dy. Para o teste dos espectros de TL, o Al2O3:C foi utilizado. Os resultados dos espectros de RL e TL mostraram concordância com a literatura, indicando que o instrumento desenvolvido é comparável a outros instrumentos em operação de outros grupos, tornando os nossos resultados confiáveis.
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BARSANELLI, CRISTIANE. "Métodos para implementação da dosimetria in vivo (dose de entrada) com dosímetros termoluminescentes na radioterapia externa com feixe de fótons." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11486.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
42
Malthez, Anna Luiza Metidieri Cruz 1985. "Desenvolvimento e caracterização de dosímetros para monitoração individual de trabalhadores ocupacionalmente expostos à radiação combinando as técnicas de termoluminescência (TL) e luminescência opticamente estimulada (OSL)." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261170.
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Orientadores: Vera Lúcia da Silveira Nantes Button, Marcelo Baptista de FreitasTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Neste estudo foi desenvolvido um dosímetro (monitor individual) para monitoração externa de indivíduos ocupacionalmente expostos à radiação (raios X e gama) que faz o uso simultâneo das técnicas de termoluminescência (TL) e luminescência opticamente estimulada (OSL - Optically Stimulated Luminescence), combinado às diferentes características dosimétricas de detectores já utilizados com a técnica TL na rotina dos Serviços de Monitoração Individual Externa (SMIEs) no Brasil (LiF:Mg,Ti ¿ TLD100, CaF2:natural, CaSO4:Dy - IPEN) e detectores utilizados com a técnica OSL, ainda pouco explorados na monitoração individual (BeO ¿ Thermalox 995) e recentemente autorizados a serem utilizados com a técnica OSL no país (Al2O3:C - Luxel). Para o desenvolvimento do monitor, diversas características intrínsecas e dosimétricas dos detectores empregando as técnicas TL e OSL em três diferentes equipamentos leitores foram avaliadas. Testes de desempenho foram aplicados ao monitor desenvolvido, conforme critérios estabelecidos no país e no exterior (CASEC e IEC, respectivamente). Os resultados obtidos demonstram que as respostas TL e OSL dos detectores dependem fortemente da configuração do leitor utilizado, da técnica empregada (TL ou OSL) e do tipo de sinal avaliado, no caso da técnica OSL (OSL total ou inicial). Assim é fundamental uma análise prévia de características intrínsecas do material, como comprimento de onda principal da emissão luminescente, tipo (inicial ou total) e magnitude (doses baixa, moderada ou alta) do sinal que será avaliado para a escolha adequada dos parâmetros do leitor (filtros, máscaras, potência, entre outros) empregando as duas técnicas. Os resultados obtidos com a técnica OSL reforçam seu uso na monitoração individual no Brasil, uma vez que estavam em acordo com a técnica TL, amplamente empregada pelos SMIEs nacionais. Além da determinação de dose individual, normalmente empregada na monitoração de trabalhadores, o dosímetro desenvolvido permite também estimar doses acumuladas ao longo do tempo, empregando a técnica OSL nos detectores de Al2O3:C ou BeO, sendo que no caso deste último, a dose única (ou individual) também pode ser determinada com a técnica TL aplicada simultaneamente no mesmo detector. Após a avaliação das respostas em energia dos detectores, um algoritmo foi desenvolvido, testado e validado para avaliar fatores de correção com respeito à energia, baseado na razão entre as respostas de um par de detectores TL e OSL. Os resultados demonstraram que as diferentes razões entre os sinais provenientes do par, permitem avaliar de forma precisa a qualidade da radiação à qual o par de detectores foi exposto. O monitor desenvolvido possui três configurações diferentes de pares de detectores, Al2O3:C/LiF:Mg,Ti, Al2O3:C/BeO e CaSO4:Dy/BeO. Ele apresenta como principais vantagens, em relação aos dosímetros já existentes em uso comercialmente, a possibilidade de poder inferir informações sobre a dose e qualidade da radiação (energia efetiva) sem a utilização de filtros e com diminuição das incertezas associadas, avaliar doses acumuladas ao longo do tempo com o mesmo dosímetro e combinar todas as características dos detectores associadas às técnicas TL e OSL, simultaneamente em um mesmo dosímetro. Os resultados dos testes de desempenho do monitor apresentaram conformidade com os critérios nacionais e internacionais estabelecidos, e contribuíram para que os critérios nacionais utilizados para a técnica TL possam ser estendidos para a técnica OSL
Abstract: In this study a dosimeter (personal monitor) for external monitoring of individuals occupationally exposed to radiation (X and gamma rays) was developed using simultaneously thermoluminescent (TL) and optically stimulated luminescence (OSL) techniques. Intrinsic characteristics of detectors already used with TL technique in External Individual Monitoring Services routine in Brazil (LiF:Mg,Ti ¿ TLD 100, CaF2:natural and CaSO4:Dy ¿ IPEN) were combined to detectors used with OSL technique, one less explored (BeO ¿ Thermalox 995), and other recently approved (Al2O3:C - Luxel) to be used in individual monitoring in the country (Al2O3:C - Luxel). During the monitor development, several intrinsic and dosimetric characteristics of detectors were evaluated employing TL and OSL techniques in three different reader equipments. Performance tests were applied to the developed monitor according to national and international established criteria (CASEC and IEC, respectively). The obtained results showed that the responses of TL and OSL detectors are strongly dependent on reader configuration, employed technique (TL and OSL) and, in the particular case of OSL technique, also the signal (total or initial OSL). Therefore, a previous analysis of the intrinsic characteristics of the material, as the main wavelength of the luminescent emission, the signal type (initial or total) and dose magnitude (low, moderate or high) must to be made in order to select the reader configuration (filters, power, and others) used with each technique. The results obtained with OSL technique reinforce its use in Brazil, as they were in agreement with TL technique, which is already largely used by national EIMS. In addition to the assess of individual dose, usually employed in workers monitoring, the developed dosimeter allows evaluating accumulated dose over time using OSL technique with Al2O3:C or BeO detectors, and single or individual doses can be evaluated applying TL technique simultaneously applied in the same detector. After the evaluation of the energy response of detectors, an algorithm was developed, tested and validated to assess correction factors with respect to energy, based on the ratio of the responses of a pair of TL and OSL detectors. The results confirm that the different ratios between signals from a detector pair allow to evaluate more accurately the radiation quality to that the pair of detectors were exposed. The monitor was developed with three different arrangements of pairs of detectors, Al2O3:C/LiF:Mg,Ti, Al2O3:C/BeO and CaSO4:Dy/BeO. It presents as main advantages, compared to existing commercial dosimeters in use, the possibility to infer information on the dosage and quality of radiation (effective energy) without the use of filters and reducing associated uncertainties, to assess cumulative doses over time with the same dosimeter, and to combine all features of the detectors associated with TL and OSL techniques, simultaneously, in the same dosimeter. The results of the performance tests of the developed monitor were in accordance to national and international criteria, and contributed to that the national criteria, used for TL technique, can also be extended to the OSL technique
Doutorado
Engenharia Biomedica
Doutora em Engenharia Elétrica
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Fung, Karl Ka Lok. "Investigation of dosimetric characteristics of the high sensitivity LiF : Mg,Cu,P thermoluminescent dosemeter and its applications in diagnostic radiology." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/752/.
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Martin, S. Rebecca. "Conception, etude et validation clinique d'un dosimetre thermoluminescent miniature pour la dosimetrie in vivo en radiotherapie metabolique." Toulouse 3, 2000. http://www.theses.fr/2000TOU30085.
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La mesure directe de la dose n'est pas realisable dans toutes les situations cliniques. Cependant, quand elle est possible, elle permet de controler et/ou ameliorer les calculs et les modeles dosimetriques utilises, en integrant tous les parametres du traitement (ponderables ou imponderables). En radiotherapie metabolique, des dosimetres de petites dimensions sont necessaires pour ne pas perturber la distribution de dose absorbee lors de la mesure et minimiser le stress lors de leur introduction puis lors de leur sejour dans le milieu biologique. Les dosimetres thermoluminescents miniatures (dimensions 0,2 0,4 5 mm 3) fabriques b. Wessels a partir de disques ptfe-caso 4:dy decoupes au microtome, ne sont pas utilisables dans les milieux aqueux biologiques car ils subissent une dissolution progressive de leurs cristaux de caso 4:dy. Nous avons fabrique un nouveau type de dosimetre thermoluminescent miniature (a base de lif:mg,cu,p) par micro-extrusion (mono-extrusion et co-extrusion) assurant les divers besoins de la dosimetrie in vivo en medecine nucleaire : _ une bonne resolution spatiale, (fils de 400 m de diametre), _ une bonne sensibilite (liee a l'utilisation de lif:mg,cu,p), _ une bonne equivalence aux tissus (z e f f8,2), _ une dynamique de mesure de 2mgy a plusieurs dizaines de gy, _ une excellente reproductibilite de detection (env. 4% sur 10 mesures), _ la stabilite du signal thermoluminescent dans l'air (0% de diminution de signal apres 1 mois), _ une forme adaptee a la manipulation, au nettoyage et la sterilisation des dosimetres, _ une stabilite dans un environnement aqueux, biologique, _ une inertie vis a vis de cet environnement (biocompatibilite). Ces dosimetres thermoluminescents miniatures font l'objet d'un brevet d'invention (brevet francais n o9903729 depose le 25 mars 1999). Ce travail s'acheve les modalites d'etalonnage et d'utilisation de ces mini-dosimetres de lif:mg,cu,p pour une determination optimale de la dose absorbee en medecine nucleaire.
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Oliveira, Fernanda Ferretti de. "Caracterização de dosímetros semicondutores e suas aplicações em técnicas especializadas em radioterapia." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-19112013-103726/.
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Introdução: A Radioterapia é frequentemente utilizada no tratamento do câncer, seja como uma modalidade simples ou em combinação com outras modalidades, tais como a cirurgia e a quimioterapia. Com o objetivo de eliminar células não desejadas no organismo humano, utiliza-se de radiações ionizantes para provocar a destruição de células tumorais pela absorção da energia da radiação incidente. A principal dificuldade encontrada em radioterapia é que as células tumorais não são tratadas isoladamente, isto é, o dano da radiação não é restrito somente às células tumorais, mas afeta também as células normais. Assim sendo, é essencial que a dose de radiação liberada nos tecidos normais seja tão baixa quanto possível para minimizar o risco de efeitos colaterais provocados pelos tratamentos radioterápicos. Objetivos: O objetivo deste trabalho é a caracterização de dosímetros semicondutores e dosímetros termoluminescentes e suas aplicações em técnicas não convencionais de Radioterapia. A partir da caracterização será possível a implementação dos dosímetros como sistema de dosimetria in vivo em teleterapia com feixe de fótons, visando atender as necessidades prementes do Serviço de Radioterapia do HCFMRP em implantar a técnica de irradiação de corpo inteiro e em realizar o controle de dose administrada ao paciente. Metodologia e Resultados: Diodos semicondutores foram caracterizados de acordo com o fator campo, angulação, taxa de dose, temperatura e fator bandeja, para obtenção dos fatores de correção. Verificou-se que a variação da resposta dos diodos com a temperatura, angulação e taxa de dose não foi significativa. Fatores campo foram calculados e registrados para campos de 3x3 cm 2 a 40x40cm 2 , onde se observou aumento na leitura do diodo com o aumento no campo. A resposta com a taxa de dose apr esentou pouca variação (de 100cGy/min para 300cGy/min a variação foi menor que 1,2%). O fator bandeja encontrado foi de 0,95±0,01 demonstrando que a presença da bandeja provoca diminuição na resposta do detector. Após a caracterização, os diodos foram calibrados em setup TBI para determinação dos fatores de calibração para cada espessura simulada do paciente (DLL). A dosimetria in vivo foi realizada em 3 pacientes submetidos ao tratamento de TBI do HCFMRP. A diferença percentual máxima entre as medidas com diodo e o valor nominal de dose foi de 3,6%, o que está de acordo com o recomendado pelo ICRU (+/- 5%). Os resultados demonstram a viabilidade e confiabilidade da técnica de dosimetria com diodos semicondutores para Controle de Qualidade de dose em tratamento de TBI. Ainda, dosímetros termoluminescentes foram caracterizados quanto à homogeneidade do grupo e a linearidade. Os fatores de calibração individuais foram encontrados e os dosímetros foram aplicados em simulações em setup TBI. Os cálculos de dose das simulações realizadas com os termoluminescentes inseridos nos orifícios de um OSA demonstraram concordância com os valores nominais de dose. Para as regiões do tórax superior e inferior, onde os TLD receberam doses mais elevadas (>150cGy), recomendou-se a utilização de compensadores de dose, para a prática clínica.Uma câmara de ionização foi utilizada como dosímetro de referência em todas as etapas de calibração e caracterização dos diodos e termoluminescentes. Conclusões: Este estudo mostrou que, para tratamentos de irradiação de corpo inteiro, quando o paciente estiver sendo preparado para um transplante de medula óssea, e o planejamento necessitar de uma grande eficácia na distribuição de dose, a metodologia com aplicações de dosímetros semicondutores apresenta-se como uma alternativa viável, precisa e de grande importância para o controle dosimétrico. Assim, ficou evidenciada a importância da utilização do diodo para o Controle de Qualidade, na avaliação da dos e a ser ministrada ao paciente, pelo menos em toda primeira fração de tratamento de TBI. Além disso, ficou demonstrada a aplicabilidade dos dosímetros termoluminescentes para controle dosimétrico, demonstrando o valor da dosimetria termoluminescente como um sistema de verificação de dose e sua eficácia como parte de um programa de garantia de qualidade em Radioterapia. A caracterização dos termoluminescentes evidenciou a possibilidade de aplicação da técnica TL em dosimetria in vivo.Introduction: Radiation therapy is often used in cancer treatment, either as a single modality or in combination with other modalities, such as surgery and chemotherapy. Aiming to eliminate unwanted cells in the human body, radiation therapy uses ionizing radiation to cause destruction of tumor cells by absorbing the energy of the incident radiation. The main difficulty in radiation therapy is that tumor cells are not separately treated. The radiation damage is not restricted solely to tumor cells, but also affects normal cells. Therefore, it is essential that the radiation dose released in normal tissues is as low as possible to minimize the risk of side effects caused by radiotherapy treatments. Objectives: The objective of this work is the characterization of semiconductor dosimeters and thermoluminescent dosimeters and their applications in non -conventional radiotherapy techniques. After characterization it will be possible to implement the dosimeters as a system of in vivo dosimetry in radiotherapy with photon beam, to meet the pressing needs of the Radiotherapy Service of HCFMRP in deploying the technique of total body irradiation and make the control of dose administered to the patient . Methodology and Results: Semiconductor diodes were characterized according to the field factor, angle, dose rate, temperature and tray factor to obtain the correction factors. It was found that the variation of the response of the diodes with temperature, angle and dose rate was not significant. Field factors were calculated and recorded for fields from 3x3 cm 2 to 40x40cm 2 , wher e there was an increase in the reading of the diode with increasing field. The response with dose rate showed small variation (from 100cGy/min to 300cGy/min the variation was less than 1.2%). The tray factor was 0.95 ± 0.01 demonstrating that the tray decreases detector response. After characterization, the diodes were calibrated in TBI setup for determining the calibration factors for each simulated patient thickness (latero-lateral distance). The in vivo dosimetry was performed in 3 patients undergoing TBI treatment in HCFMRP. The maximum percentage difference between the measurements and the diode nominal dose was 3.6%, which is consistent with that recommended by ICRU (+ / - 5%). The results demonstrate the feasibility and reliability of the dosimetry technique with semiconductor diodes for dose quality control in TBI treatments. Still, dosimeters were characterized by group homogeneity and linearity. The calibration factors were found and individual dosimeters were applied in simulations with TBI setup. The dose calculation of simulations performed with the thermoluminescent inserted in holes of the phantom showed agreement with the nominal dose. For regions of the upper and lower thorax where TLD received higher doses (> 150cGy) it was recommended the use of compensating dose in clinic. An ionization chamber dosimeter was used as reference in all stages of calibration and characterization of diodes and thermoluminescents. Conclusions: This study showed that, for total body irradiation treatments, when the patient is being prepared for a bone marrow transplant, and planning requires a great effect on the dose distribution, the methodology with semiconductor dosimeters presented a viable alternative, and has great importance for the dosimetric control. The study proved the importance of diode semiconductors for quality control, for evaluation of the dose to be administered to the patient, at least throughout the first fraction of TBI treating. Furthermore, it was demonstrated the applicability of TLD for control quality, demonstrating the value of thermoluminescent dosimetry as a dose verification system and its effectiveness as part of a program of quality assurance in radiotherapy. The characterization of thermoluminescent showed the possibility of applying the TL technique in in vivo dosimetry.
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Abdul, Sani Siti F. "Characterisation of defects and thermoluminescence yield of novel tailor-made doped optical fibres for dosimetry." Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/808286/.
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This work encompasses characterisation of defects and dosimetric studies of novel tailor made doped SiO2 fibres. Present studies have been carried out seeking to improve upon the thermoluminescence (TL) yield of commercially produced small diameter telecommunication optical fibres. Using the modified chemical vapour deposition (MCVD) process, the optical fibres have been fabricated to a range of dopant concentrations of nominal value 6- 8- and 10 wt%. In this study, three different types of optical fibres have been utilised, made using the same doped preform. The doped fibres are cylindrical fibres (CF), flat fibres (FF) and photonic crystal fibres (PCF). It should be noted that the process of fibre drawing has been found to produce defect centres, influencing characteristics of optical fibre and TL response. To seek support of this, an X-ray Photoelectron Spectroscopy (XPS) study of a Ge doped SiO2 fibres sample has been undertaken to determine the oxidation state of Ge. Results from this have confirmed the efficiency of the surface analysis technique, leading to understanding of the Ge structure. Following on from this, facilities supporting characterization of the fibres are outlined, including an ion beam facility used for Particle Induced X-ray Emission (PIXE)/Rutherford Back Scattering (RBS) analysis to localize and determine the concentration of Ge dopants. Building upon these characterisations, thermoluminescence studies were carried out. For the first of the experiment, undoped flat fibres were used, comparison of response being made with that of conventional TLD-100 and commercial Ge-doped silica fibres. The undoped flat fibres provide competitive TL yield to that of TLD-100, being some 100 times that of the Ge-doped fibres. Pt-coated flat fibres have then been used to increase the photoelectron production and hence local dose deposition, obtaining significant increase in dose sensitivity over that of undoped flat fibres. Using 250 kVp X-ray beams, the TL yield reveals a progressive linear increase in dose for Pt thicknesses from 20 nm up to 80 nm. Finally, to illustrate the potential of novel tailor-made doped SiO2 optical fibres, the dosimetric characteristics that have been investigated include, dose response, glow curves and energy dependence. Taking TLD-100 as a benchmark, results are presented for Ge-doped, Ge-B-doped and Ge-Br-doped optical fibres. The dose response of doped silica fibres was found to be linear over the range 2 cGy up to 50 Gy, also showing good dosimetric response for low photon energies. Additional investigation of the same doped SiO2 optical fibres have been conducted for measurement of TL yield from the high linear energy transfer (LET) radiation offered by a liquid 223Ra alpha particle source.
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Santos, Lindomar Soares dos. "Implementação de um sistema dosimétrico termoluminescente para utilização em dosimetria in vivo em teleterapia com feixes de fótons de energia alta." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-12052008-150030/.
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A dosimetria in vivo é a verificação final da dose real administrada ao paciente e tornou-se atualmente necessária devido ao aumento da complexidade e da sofisticaçã das técnicas radioterápicas. A finalidade deste trabalho foi apresentar, verificar e avaliar alguns procedimentos básicos, práticos e viáveis para a implementação da dosimetria in vivo com dosímetros termoluminescentes na verificação de dose em um serviço de radioterapia. Para o estabelecimento do sistema dosimétrico termoluminescente, alguns testes e medições foram realizados, incluindo o procedimento de inicialização, a determinação da homogeneidade do grupo de dosímetros, a determinação do fator de correção individual de cada dosímetro, a determinação da faixa de linearidade do sistema e do coeficiente de calibração. Medições em um objeto simulador antropomórfico foram realizadas para garantir que os métodos utilizados são satisfatórios antes que estes fossem usados para medições em pacientes. Medições de dose em um paciente foram feitas em um tratamento de câncer de próstata. A metodologia proposta pode ser usada como parte de um programa de garantia de qualidade em um serviço de radioterapia.In vivo dosimetry is the ultimate check of the actual dose delivered to an individual patient and has become a procedure actually necessary due to increasing complexity and sophistication of radiotherapy techniques. The purpose of the present work was to present, verify and evaluate some basic, practical and viable procedures for the implementation of in vivo dosimetry with thermoluminescent dosimeters for patient dose verification at a radiotherapy service. For the setting up of the thermoluminescent dosimetric system, several tests and measurements were carried out including the initialisation procedure, the determination of the batch homogeneity, the determination of individual correction factor of each dosimeter, the determination of linearity range of the system and its calibration coefficients. Anthropomorphic phantom measurements were taken to ensure that the methods are satisfactory before they are used for patients measurements. Patient dose measurements were carried out in a prostate cancer treatment. The proposed methodology can be used as a part of a quality assurance program in a radiotherapy service.
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BRAVIM, AMANDA. "Avaliacao de dosimetros termoluminescentes empregando objetos simuladores equivalentes a agua para aplicacao na dosimetria de feixes clinicos de eletrons." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9625.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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MARRE, DELPHINE. "Evaluation des perturbations induites sur la mesure de la dose absorbee avec des chambres d'ionisation, des dosimetres chimiques et des dosimetres thermoluminescents dans des faisceaux d'electrons de haute energie." Toulouse 3, 2000. http://www.theses.fr/2000TOU30083.
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Le but de cette these est d'ameliorer la precision sur la determination de la dose absorbee avec des detecteurs usuels en radiotherapie, en particulier les chambres d'ionisation, les dosimetres chimiques et les dosimetres thermoluminescents (dtl), dans des faisceaux d'electrons de haute energie. En effet, la composition de ces detecteurs est generalement differente de celle du milieu environnant, ce qui engendre des perturbations sur la mesure de la dose absorbee. Le but recherche est de determiner les differents facteurs de correction qui sont associes a ces detecteurs dans les faisceaux d'electrons de 6 a 50 mev. Une approche experimentale et deux approches theoriques sont menees : la dosimetrie de fricke est prise comme reference pour la partie experimentale. Des calculs par la methode de monte carlo (egs4 et penelope) et la theorie generale de la cavite sont utilises pour la theorie. Les resultats theoriques sont ensuite confrontes aux mesures. La determination de la dose absorbee avec les chambres d'ionisation dans les faisceaux d'electrons s'effectue par l'application des protocoles de dosimetrie (par exemple iaea 1997 et 2000). Ces protocoles donnent des valeurs de facteurs de correction plus ou moins approchees pour certaines chambres d'ionisation, alors que d'autres ne sont pas repertoriees. Notre etude consiste a evaluer avec la meilleure precision possible les facteurs de correction de perturbation et de correction de qualite de faisceau pour les chambres d'ionisation plates et cylindriques. Notre etude des dtl consiste a evaluer le facteur de correction de qualite de faisceau pour le lif sous forme de poudre (dtl937). L'energie du faisceau d'electrons, les dimensions du dtl et la nature du milieu environnant sont les parametres d'influence etudies. Les resultats obtenus sont actuellement directement appliques pour la determination de la dose absorbee par dtl dans le laboratoire europeen de controle de qualite en radiotherapie equal-estro installe a l'igr.
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Takam, Rungdham. "Determination of dose distribution of Ruthenium-106 Ophthalmic applicators." Title page, contents and abstract only, 2003. http://web4.library.adelaide.edu.au/theses/09SM/09smt1363.pdf.
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"August 2003" Bibliography: leaves 108-117. 1. Ruthenium-106 ophthalmic applicators -- 2. General principle of thermoluminescent dosimeter -- 3. Study of basic characteristics of CaSO4:Dy TLD -- 4. Measurements of COB and CCA type ruthenium-106 ophthalmic applicator dose distributions -- 5. Determination of the dose rate distribution using a MOSFET detector -- 6. Summary and conclusion. In this project, small CaSO4:Dy TLDs and a semiconductor MOSFET dosimeter were used for the determination of on-axis depth dose-rate distributions of 15-mm and 20-mm ruthenium-106 applicators in acrylic eye phantoms. The TLDs were also used to determine off-axis dose distributions.