Desenvolvimento de um sistema automatizado de posicionamento para dosimetria em teleterapia

Abstract

Radiotherapy can be divided into two modalities: brachytherapy and teletherapy, the latter being the most widespread technique. Teletherapy equipment is capable of producing beams of photons or electrons that leave the equipment towards the patient positioned on the treatment table. To ensure that the irradiation field provides the correct dose and the beams produced focus only on the region of interest, a series of quality control tests performed on the equipment are necessary, part of these tests being performed using specific equipment for dosimetry: a dosimetric set (ionization chamber and electrometer), in addition to a simulator (phantom) filled with water that simulates the interaction of the beam with the human body. Depending on the amount of energy that the linear accelerator can produce, and considering that the quality control must be carried out periodically on each of the energies available in the equipment, the whole process turns out to be too slow and time-consuming when using a manual drive simulator compared to automated equipment. The automated equipment currently available on the market is expensive and imported, or those that have a lower price are devices that carry out the automated movement only in the vertical direction, which does not solve the problem at all, because in the evaluations of the profile of the beams, for example, it is necessary to move the ionization chamber horizontally, leading to the manual process again. Thus, this work sought to develop an automated simulator system, both in the vertical and horizontal direction, at low cost, using open source microcontroller boards (Arduino platform) as a basis for development. The tests carried out on the developed equipment demonstrated its ability to carry out movements in both directions, positioning the ionization chamber in the desired position, with an accuracy of around tenths of a millimeter, equivalent to imported equipment at a higher price, with the mechanism being remotely controlled by a central that is positioned outside the treatment room, since the objective is to prevent the operator from entering the room during the procedure. And it is also expected, in a future work, to develop a software that, together with the equipment, is capable of carrying out the process of scanning the radiation beam, which would make this equipment equivalent to those that are currently available only by import and from high cost reaching its value in the order of U$ 100,000.00 (one hundred thousand dollars), such as the Blue Phantom (IBA) or the BeamScan (PTW).