Validation of the planar dose and point dose according to the AAPM TG-119 protocol for VMAT technique on Halcyon linear accelerator

This study aims to present the validation of the volumetrically modulated arc radiotherapy technique (VMAT) in the Halcyon equipment, by Varian®, using the TG-119 protocol of the American Association of Physicists in Medicine (AAPM). The TG-119 protocol brings together several target structures for planning as well as the objectives defined for optimization. The reverse planning was carried out in the Eclipse software. The plans were executed in the linear accelerator Halcyon with a maximum energy of 6MeV-FFF (Flattening Filter Free) for photons. The results obtained showed that the difference between the planned dose and the average of the point dose measurements was 0.4% and for gamma analysis, the agreement was in 98.72% of the points, thus passing the gamma criterion. The confidence limits reached for the high dose region, low dose region and planar dose analysis were within the values stipulated in the AAPM TG-119 protocol. Thus, it was concluded that the planning system used with the VMAT technique is suitable for daily use in Halcyon, since the values found are within the limits stipulated by the AAPM protocol TG-119. (author)