Análise das peculiaridades do tratamento de câncer de pulmão com radioterapia estereotáxica utilizando arco volumétrico modulado e feixe sem filtro achatador

Abstract

This work evaluates the possible over and under dosages in the tumor and organs at risk due to the interplay that can occur between the tumor movement and the multileaf segmentation in lung cancer treatment with stereotactic radiation therapy with modulated intensity technique. In addition, it also investigates, for the same planning, the possible effects that can result with different collimator rotations and the use of energies with and without a flattening filter. A phantom that simulates lung movement was used for the realistic simulation of a lung cancer treatment in a linear accelerator TrueBeam and a cylindrical ionization chamber for the dose measurements. The results show that the best option is the arrangement of arcs with two semi-arcs of 180 degrees plus 30 degrees and collimator rotation at 45 degrees; while the worst option is technique with a full arc and collimator at 0 or 90 degrees. The experimental results show that the greater the range of tumor motion the greater its underdosing, reaching up to 20%, therefore for large movements, greater than 1,5cm, the use of an abdominal compressor is recommended.