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Measured and calculated (MCNPX) lateral profile -Varian 2100c LINAC with 6 MV beam and 10×10 cm² field.
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There is a serious, and growing concern about the increased risk of the emergence of a secondary cancer, radio-induced, associated with radiotherapy treatments. To assess the radiation doses to organs outside the target volume, in this work, several computational exposure scenarios were modelled, based on Monte Carlo simulation (MCNPX code). A Vari...
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Citations
... The validation of the properties of the X-ray beam through the percentage depth dose (PDD) and the lateral dose profile (off-axis) are fundamental aspects to test the computational model of the accelerator and guarantee the reliability of the simulation results. This task has already been performed through comparisons with experimental data (Bednarz et al., 2009;Santos et al., 2021;Catusso et al., 2021). To further improve the Varian 2100c LINAC, in this work, a field adjustment mirror and a monitoring ionization chamber were implemented, as we believe that this equipment could impact the results since they are located along the X-ray beam. ...
To calculate the risk of secondary cancer induction resulting from this dose through a Monte Carlo simulation code and voxel-based anthropomorphic phantom to determine the radiation dose in organs and/or tissues with dosimetric importance and the effect of using static MLC in the 3D-CRT technique. In this work, a radiotherapy treatment of breast cancer was simulated using the radiation transport code MCNPX 2.7.0 and the adult anthropomorphic simulator FSTA_H50_M50. The absorbed doses for a set of organs with dosimetric importance were determined. A LINAC Varian 2100C device operated with two techniques was simulated: 2D with open field (OF) and 3D-conformational (3D-CRT), the latter with the use of a multilayer collimator (MLC) of the breast, both acting with 6 MV energy. The highest values of absorbed dose were obtained for the ipsilateral lung (7.22 Gy (3D-CRT) and 8.49 Gy (OF)) and the contralateral breast (6.29 Gy (3D-CRT) and 6.56 Gy (OF)), generating for these organs the greatest risks of secondary cancer induction. With the OF technique, due to the non-collimation of the beam, there was an increase in the absorbed dose in all organs compared to 3D-CRT, thus evidencing a more effective treatment with the 3D-CRT technique, improving both homogeneity and conformity with the dose absorbed in the target organ.
