Evaluación de un arreglo de diodos en 2 dimensiones para dosimetría física y clínica de rutina en haces de electrones en radioterapia

Abstract

In this study, we intend to show the feasibility of using a 2-dimensional diode array for routinely electron dosimetry. We calibrated the array with energies 9, 12 and 16 MeV, and evaluated the central beam axis dose, flatness, symmetry and short term reproducibility against measurements with parallel-plane ionization chamber. We used gamma analysis for comparison of exported and measured fluencies. In short term reproducibility the variation coefficient was less than 1.0 % for all the energies. The absolute difference in flatness and symmetry was less than 3.0 %. In the gamma analysis, the percentages of the diode array data points that match with the planned dose were: 90.8 % to 97.9 % for 9 MeV, 52.7 % to 81.7 % for 12 MeV and 69.2 % to 94.2 % for 16 MeV. The absolute differences between the planned and measured dose were less than to 2.0 %, except for 12 MeV (3.2 %). The agreement between the data obtained with ionization chamber and the diode array supports the use of Mapcheck as a trustable method for electron dosimetry.