ESTRO 2024 - Abstract Book

S4203

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2024

Conclusion:

The utility and practicality of model-based CT were demonstrated through our clinical 5DCT protocol for lung cancer patients. The clinic was provided 8 CT scans at conceptually similar breathing phases as 4DCT but with the following advantages: 1) No sorting artifacts, 2) Two independent accuracy metrics, the motion model residual, and an overlap of the 25 helical CT scans and their model-based reconstructions. The relatively low correlation between breathing irregularity and model performance indicated that model-based CT is robust to irregular breathing and the greater correlations between image registration quality and overall model performance and model residual indicate that image registration robustness needs to be improved. We feel that the failure rate of 12% is not optimal and we are investigating improved image registration approaches to reduce this number, as well as improved alternative analysis techniques.

Overall we find model-based CT extremely promising and will continue to develop this technology as well as downstream applications, including model-based cone-beam CT patient positioning and breathing gating.

Keywords: breathing motion, model-based CT, 5DCT

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