ESTRO 2023 - Abstract Book

S1453

Digital Posters

ESTRO 2023

that are always performed (see table and figure). Any error found by these checks are highlighted on the associated CT slice in a graphical user interface (see figure). In addition, the application supports 5 structure QA XML commands (see table). For example, the CompareContours command can detect an incorrect GTV-CTV margin even if a substantial part of the CTV subsequently is cropped to anatomical structures. At present, Structure Tool is used for 52 treatment techniques including more than 90 % of all curative patients in our clinic.

Results Structure Tool has analyzed more than 3000 structure sets since its clinical introduction in 2020. The application has detected numerous structure errors, thereby preventing serious treatment errors like missing boluses, incorrect GTV-CTV margins, target structures not fully included in elective volumes, match structures with an incorrect margin, and too large PTVs due to stray voxels. Conclusion Structure Tool provides comprehensive fully-automated structure QA of target and OAR structures, thereby improving treatment quality.

PO-1734 Daily Elekta Unity beam checks with the on-board MV imager during the first year of clinical use

G. Hilgers 1 , M. Ikink 1 , I. Potters 1 , D. Schuring 1

1 Radiotherapiegroep, Medical Physics, Arnhem/Deventer, The Netherlands