Dedico este trabalho À minha amada Izabel Pinheiro, por todo amor, incentivo, paciência e por estar sempre presente, mesmo na ausência. AGRADECIMENTOS À Dra. Laura Natal Rodrigues, minha orientadora, pela oportunidade, conselhos e incentivo acadêmico. Aos meus avós, Francisco Edmar (in memorian) e Maria Eunice, Edmilson Moreira (in memorian) e Terezinha de Lavor, que sempre me ajudaram e orientaram muito. Aos meus pais, Marcelo e Margarida, que nunca mediram esforços para ajudar na minha formação, com certeza, eles são os melhores do mundo! Aos meus irmãos, Rafael e Pedro, por serem bons amigos e parceiros em todas as horas. À toda equipe do departamento de radioterapia do Hospital das Clínicas de São Paulo, por terem permitido o uso dos aparelhos e materiais necessários para o desenvolvimento do trabalho. Aos físicos, Marcos, Ana Paula e Marco, pelas valiosas discussões. Aos amigos de residência, Cristian, Ângela e Caroline, pelos ensinamentos e ajuda sempre que era necessário. Aos colegas de mestrado, Eduardo, Bruno e Talita, pelas horas de estudo e parcerias. Aos professores do IPEN, pelos valiosos ensinamentos.
ABSTRACTIntensity modulated radiation therapy (IMRT) is currently been implemented in a rapidly growing number of centers in Brazil. As consequence many institutions are now facing the problem of performing a comprehensive quality control program before and during the implementation of IMRT in the clinical routine practice.The aim of this work is to evaluate and propose a methodology for quality assurance in IMRT treatments.An ionization chamber and a two-dimensional array detector were performed to assess the absolute value of the total dose of all fields in one specific point. The relative total dose distribution of all fields was measured with a radiochromic film and a two-dimensional array at one depth in a phantom. A comparison between measured and calculated dose distributions was performed using the gamma-index method, assessing the percentage of points that meet the criteria of ±3% dose difference and ±3 mm distance to agreement.As a result of 113 tested IMRT beams using ionization chamber and 81 using two-dimensional array, the proposal was to take an action level of about ± 5% compared to the treatment planning systems and measurements, for the verification of the dose in a single point at the low gradient dose region. Analysis of the two-dimensional array measurements showed that the gamma value was <1 for 97.7% of the data and for the film the gamma value was <1 for 96.6% of the data.This can be concluded that for an accurate delivery of dose in "slidingwindow" IMRT with micro multileaf collimator, the absolute value of the total dose and the relative total dose distribution should be checked by absolute and relative dosimetry respectively.
