Verificação das margens de PTV para IMRT de câncer de próstata utilizando EPID
DOI:
https://doi.org/10.29384/rbfm.2014.v8.n3.p18-21Abstract
Este trabalho tem como objetivo apresentar o resultado de uma estratégia de definição das margens de PTV para pacientes com câncer de próstata tratados com a técnica IMRT, devido às incertezas geométricas associadas ao posicionamento planejado. Foram obtidas 341 imagens de 31 pacientes em decúbito dorsal, antes da aplicação das frações, utilizando-se um EPID anexado a um acelerador linear. Foram estudados somente os erros de setup. Os deslocamentos foram analisados em relação às direções AP (antero-posterior), CC (crânio-caudal) e LL (latero-lateral). Os valores de desvio padrão da distribuição dos deslocamentos sistemáticos foram de 0,12 cm, 0.06 cm, 0,02 cm e o desvio padrão da distribuição dos desvios aleatórios foi de 0,62 cm, 0,53 cm, e 0,24 cm nas direções AP, CC e LL, respectivamente. A avaliação dos dados, de acordo com o método de Stroom e Heijmen, sugere que as margens de PTV devem ser de 0,66 cm na direção AP, 0,49 cm na direção CC e 0,20 cm na direção LL. Estes dados mostram uma alta reprodutibilidade no posicionamento dos pacientes, dado através de um método para a correção da posição planejada em relação à anatomia óssea verificada com o EPID.Downloads
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