ESTRO 2024 - Abstract Book

S4397

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

ESTRO 2024

Results:

The RMSE of the leave positions at 12cm/s was 0.4mm and for the jaws at 8cm/s this was 0.3cm/s.

The prediction accuracy RMSE ranged from 0.8mm (225ms) to 1.1mm (300ms).

Figure 2 shows the time-resolved results at the caudal GTV edge (PSD5) for the different adaptation modes indicating dose deviations per breath and heartbeat. The PSDs revealed that without MLC tracking the cardiorespiratory motion caused dose differences of 0-23% for the squared field and 2-19% for the IMRT plan compared to their corresponding static deliveries. Largest differences were found at the cranial PTV edge (PSD1). Applying MLC tracking without predictor reduced these differences to 0-9% and 1-16%. Especially around the caudal GTV and PTV edge (PSDs 4-6) these dose differences were reduced to only 0-4%. MLC tracking with a predictor fully restored the static dose distribution with dose differences of ≤1% for the squared field and <5% for the IMRT plan.