Characterization of nanofilms of ZnO and MnO semiconductors in radiotherapy beams

The advancement of nanotechnology encourages researches to develop innovative sensors and techniques for measuring several physical quantities and providing new applications, for example, the dosimetry in radiotherapy. The purpose of this work is to use nanofilms of zinc and manganese oxide semiconductors for dosimetric applications in radiotherapy photon beam. Samples of nanofilms were manufactured by sputtering technique and deposited on a glass substrate. Tests in a clinical linear accelerator were performed to analyze the response of nanofilms in beams of 6 MV and 10 MV. The results demonstrated that the nanofilms of both oxides exhibit ohmic behavior when characterized electrically and demonstrated both repeatability and reproducibility in the measurements of the photon intensity of the beam in radiotherapy. Although these materials do not agree with the standard detector used in radiotherapy for measurements in depth dose, the beam profile of these materials demonstrates congruence with the standard detector, in addition these semiconductors showed practically linear behavior with the dose rate, although they have a dependence with angle of incidence of the photon beam and little dependence with size of the radiation field for fields larger than 15 x 15 cm², which indicates the need of other studies for the technological development in the geometry of nanofilm. In general, these semiconductors have proved to be a technological innovation regarding their application to dosimetry in radiotherapy. (author)