Room: ePoster Forums
Purpose: The use of Winston-Lutz (WL) test for isocenter verification, prior to a radiosurgery procedure, is recommended in TG101. The objective of this work was to develop an automatic WL test procedure using XML script with the developer mode of a TrueBeam STx.
Methods: The WL test consist in the setup of a WL phantom (Brainlab) with the mechanical isocenter of the TrueBeam STx (Varian). After verification, 12 EPID images (aS1200), with different combinations of gantry (0, 90,180, 270 deg), collimator (90, 270 deg) and couch (0, 45, 90, 270, 315 deg) angles are obtained. EPID images are analyzed by RIT software v6.7 (Radiological Imaging Technology) to obtain the deviation between radiation and mechanical isocenter. An XML script was created in the development environment Microsoft Visual Studio Community (2017). The script contains automatization sequences with specific control points including acquisition of all images. The XML file is executed in the Developer Mode version 2.0. Comparison between manual and automatic WL were done for 5 procedures based on execution time, WL displacement and 3D maximum displacement are compared.
Results: The XML routine run satisfactorily without any bug. The average execution time for manual and automatic WL test was 12.7Â±0.2 min and 4.28Â±0.02 min respectively. The WL displacement for manual and automatic was 0.58Â±0.04 mm and 0.50Â±0.10 mm respectively and the WL 3D maximum displacement for manual and automatic was 0.61Â±0.06 mm and 0.75Â±0.05 mm respectively.
Conclusion: The automatization of WL test using XML script is feasible and reduces the execution time and the displacement obtained are the same to the obtained manually. XML script and Developer Mode improves test WL time efficiency. Adaptations of the current XML are being extended to automate others quality controls in our institution.
Radiosurgery, Quality Control, Computer Software
TH- External beam- photons: Quality Assurance - Linear accelerator