ESTRO 2025 - Abstract Book

S2759

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2025

Conclusion: Philips MRCAT sCT appears to be a promising alternative for MR-only workflow, and may allow omitting the simulation CT. This can reduce systematic errors due to patient positioning and fusion with MRI, as well as unnecessary patient doses.

Keywords: Synthetic CT, MR-linac, optimization

References: Christiansen, R. L., Jensen, H. R., & Brink, C. (2017). Magnetic resonance only workflow and validation of dose calculations for radiotherapy of prostate cancer. Acta Oncologica , 56 (6), 787-791. Maspero, M., Savenije, M. H., Dinkla, A. M., Seevinck, P. R., Intven, M. P., Jurgenliemk-Schulz, I. M., ... & Van Den Berg, C. A. (2018). Dose evaluation of fast synthetic-CT generation using a generative adversarial network for general pelvis MR-only radiotherapy. Physics in Medicine & Biology , 63 (18), 185001.

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Digital Poster Plan evaluation tool for multi-mets SRS plans using isodose islands to capture brain dose parameters LiCheng Kuo 1 , Michalis Aristophanous 1 , Luke Pike 2 , Åse Ballangrud 1 1 Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York City, USA. 2 Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York City, USA Purpose/Objective: Recent advances in stereotactic radiosurgery (SRS) have enabled treating an increasing number of brain metastases (BMs) in a single course. As the number of BMs increases, accurate plan quality evaluations such as the Conformity Index (CI), Gradient Index (GI), and brain dose become critical in evaluating the risk of radiation necrosis. While HyTEC [1] has identified key dosimetric predictors for radiation-induced brain toxicity, current treatment planning systems (TPS) often only provide global dosimetric information and cannot accurately calculate local brain volume parameters compatible with HyTEC data report recommendations, particularly when BMs are close together. This limitation hinders the assessment of treatment plan quality and the optimization of dose delivery for multiple BMs. This study’s objective was to develop a software solution for accurately identifying specific dose islands surrounding each lesion or lesion group, enabling precise dosimetric information for clinical evaluation, quality assurance, and correlation with toxicities and treatment outcomes.