Caracterización física y dosimétrica del colimador multiláminas del Acelerador Lineal Elekta Synergy del Hospital Carlos Andrade marín para uso en radioterapia de intensidad modulada.

Abstract

In Carlos Andrade Marín Hospital, the technique of Intensity Modulated Radiation Therapy (IMRT) will be implemented to offer an improvement in the treatments, radiotherapeutic controls and to be used in situations in which the Three-dimensional Conformational Radiation Therapy (3D-CRT) has limitations. The objective of this work was to contribute to the characterization of the Multileaf Collimator (MLC) as a system of delivery and modulation of IMRT, both in its physical and mechanical aspects that will have a great impact on the dosimetric characteristics and therefore on the final dose administered. For the characterization of the MLC, several dosimetric parameters were evaluated, working with energy of 6MV, being among them: the transmission factor, percentage of dose to depth for fields conforming with different collimation systems characteristics of Linear Accelerator (LINAC), with Penumbra for two fields sizes at maximum and reference dose depth, total dispersion and collimator factors for fields conforming to conventional jaws, back jaws and multilamines together. With the dosimetric information the mechanical characteristics such as the isa-eccentricity of the MLC, the positioning accuracy and the reproducibility of the plates were evaluated using a diode array called MapCHECK 2, which, thanks to the tools of the SNC Patient Software, it allowed to analyze the characteristics mentioned. In addition, the functionality of the MLC system was evaluated by forming fields in the Planning System and printing templates that were later used for verification of transfer and shaping of fields in the LINAC. Based on these tests, it was concluded that the linear accelerator multilayer collimator Elekta Synergy has both physical and dosimetric characteristics so that it can act as a delivery and modulation system in Radiotherapy treatments with Modulated Intensity. In order to discriminate between intralamin and interlamin transmission it is advisable to used dosimetry per film.