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Previous issue date: 2016-08-29 / Despite the activities administered to patients during Positron Emission Tomography (PET) scans are guided by methods and reference levels, in clinical practice there is a great discrepancy between these values. Current indications use dependent patient parameters (DPP), such as age and weight, without considering an assessment of the resulting image quality. The purpose of this study is to investigate how the anthropometric and physiological characteristics of patients influence the determination of 18F-FDG activity to be administered in PET/CT scans and image quality. Therefore, we conducted a preliminary study with three simulators of different diameters, representing patients with different sizes, with different values of activity concentration. Subsequently, we performed a retrospective study on a PET/CT image database acquired with 18F-FDG. Image quality indicators (NECR, and NECRN and SNRnorm) of the images of patients were determined for many PDP, namely: body weight, BMI, BSA, fat mass, mass-height ratio and equivalent diameter. The relationship between the administered activity, counts rates and the PDP, with image quality indicators were statistically evaluated. We concluded that the NECRN is the quality indicator which has the best correlation between the PDP, particularly with body mass and BMI. The image quality in can be estimated from the true coincidence events rate (TRUES) during PET/CT acquisition with 18F-FDG, due to the highly linear relationship with NECR for different body mass or BMI ranges, allowing the optimization of the administered activity based on the physical characteristics of the patient. / Apesar das atividades administradas a pacientes durante exames de Tomografia por Emiss?o de P?sitrons (PET) serem norteados por m?todos e n?veis de refer?ncia, na pr?tica cl?nica h? uma grande discrep?ncia entre esses valores. As indica??es atuais utilizam par?metros dependentes do paciente (PDP), como idade e peso, sem considerar uma avalia??o da qualidade da imagem obtida. A proposta deste trabalho ? investigar como as caracter?sticas antropom?tricas e fisiol?gicas dos pacientes influenciam na determina??o da atividade de 18F-FDG a ser administrada em exames de PET/CT e na qualidade das imagens. Para tanto, foi realizado um estudo preliminar com tr?s simuladores de diferentes di?metros, representando pacientes com tamanhos distintos, com valores distintos de concentra??o de atividade. Posteriormente, foi realizado um estudo retrospectivo em um banco de imagens de exames de PET/CT com 18F-FDG. Foram determinados indicadores de qualidade (NECR, NECRN e SNR) das imagens dos pacientes para diversos PDP, a saber: massa corporal, BMI, BSA, massa gorda, rela??o massa-altura e di?metro equivalente. Foram avaliadas estatisticamente as rela??es entre as atividades administradas, as taxas de contagens e os PDP, com os indicadores de qualidade da imagem. Conclui-se que a NECRN ? o indicador de qualidade que possui a melhor correla??o entre os PDP, particularmente com a massa corporal e o BMI. A qualidade da imagem pode ser estimada atrav?s da taxa de eventos de coincid?ncia verdadeira (TRUES) durante a aquisi??o das imagens de PET/CT com 18F-FDG, em virtude da rela??o altamente linear com o NECR para faixas distintas de massa corporal ou BMI, possibilitando a otimiza??o da atividade administrada em fun??o das caracter?sticas f?sicas do paciente.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/7074 |
| Date | 29 August 2016 |
| Creators | Martini, J?lio C?sar |
| Contributors | Silva, Ana Maria Marques da |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Engenharia El?trica, PUCRS, Brasil, Faculdade de Engenharia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 207662918905964549, 600, 600, 600, -655770572761439785, 4518971056484826825 |
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