ESTRO 2024 - Abstract Book

S3346

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

The phantom was designed in-house and precision manufactured in collaboration with the University of Oxford. The modular phantom body was constructed with PMMA for economy. The 15mm spherical targets are encased in PMMA cubes and segmented to accommodate bespoke laser-cut radiochromic film. Blank PMMA and cylindrical PEEK inserts are included to fill air gaps and allow for image-guidance respectively. A software platform has been developed to import and process film images, extract and register the corresponding dose planes from the DICOM dose and perform analysis. A treatment plan was created in the TPS (Eclipse, Varian Medical Systems, Inc) for a test configuration of targets. The phantom was loaded with film and the plan delivered on a Varian TrueBeam equipped with HyperArc and a HD120 MLC.

Results:

Initial proof-of-principle testing has thus far indicated a 3D Euclidean agreement of <0.7mm when comparing the centroids of the 70% isodoses from the measured films and corresponding dose planes. The workflow was found to be practical enough for periodic QA with a phantom preparation time of ~20 minutes, plan delivery time of ~15 minutes and processing/analysis time of ~30 minutes.