Calculo da dose de radiação atraves de convoluções em meios heterogeneos para aplicações em radioterapia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

In this thesis we have applied the convolution techniques to calculate the three dimensional (3D) dose distribution to be used in teletherapy. The convolution method spans the total dose in three parts: one due to the energy released by charged particles produced at the first collisions, one due to the energy released by the first scattered photons, and the last one due to photons of higher order scattering. We have shown up the theoretical development for homogeneous and inhomogeneous media. Cross sections of tissues have been approximated to water like. Heterogeneities are supposed to have the same cross sections as water and their densities have been treated as weight for the dose computations. Electron and photon functions were simulated in a previous step using EGS4. We have done the calculations for 60Co energy and the results have shown good agreement with experimental data sets for .elds less than 10 x 10 cm2 at 26 cm depth. For larger fields the depth of agreement was reduced. We have associated this fact to the limitation of simulation steps, during transport of photons of higher order scattering. The aim of the software developed to calculate the radiation dose distribution in this thesis is to be the basis for other studies and researches related. The appliance in radiotherapy routine will be evaluated after confiability tests

ASSUNTO(S)

radiação - transferencia radioterapia energia - transferencia radiação - dosagem fotons - transporte eletrons - transporte

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