ESTRO 2021 Abstract Book

S1349

ESTRO 2021

that has a good correlation with our reference metric G(2,2) AC . In this analysis, case-0 is always the reference dose TPS and a minimum threshold of 10 % of the maximum dose was selected. Results Daily irradiation (6 days) of a 10 x 10 field in the IW showed a lack of mechanical stability: 0.3 ± 1.6 mm in the transverse axis to the table (T) and 0.7 ± 0.2 mm in the longitudinal axis (L). These values were obtained using the Autocentering EP tool. In view of these results, this option is always applied. Case-a already has an appreciable dosimetric impact on DHV. However, random displacements up to 2 mm have a minor impact on them (see Fig. 1).

An acceptable correlation was found between G(2,1) EP

and G(2,2) AC.

The results are summarized in figure 2,

which also includes the metric G(2,1) TPS

as a reference value associated with dosimetric impact. There is no

significant difference, at least at the level of analysis of this work, between prostate and H&N.