S2192
Physics - Inter-fraction motion management and daily adaptive radiotherapy
ESTRO 2026
(+55.8cGy, median +9.2cGy), esophagus (+44.4cGy, median +0.8cGy), and constrictor_inferior (+32.8cGy, median +19.2cGy). Largest decreases: lips (-47.6cGy, median -22.4cGy) and brainstem max (-31.6cGy, median -9.5cGy). Greatest dose variability observed in brachial plexi (SD: 344cGy right, 246cGy left), pharyngeal constrictors (SD: 208cGy middle, 195cGy inferior), and parotid_R (SD: 199cGy).Target coverage metrics showed dose variations ranging from -29.8% to +19.2% across different PTV dose levels, with PTV_6996 V100% demonstrating the largest mean deviation (-2.1%).
(2024). Keywords: Reinforcement Learning,real-time,plan optimisation
Digital Poster 4650 Evaluation of automated offline dose
accumulation in head and neck radiotherapy: a pre-clinical analysis using ChartCheck Adaptive David Barbee Radiation Oncology, NYU Langone Health, New York, USA Purpose/Objective: Accurate dose accumulation accounting for anatomical changes during radiotherapy remains a significant challenge in clinical practice. The current radiotherapy paradigm typically assumes static patient anatomy throughout the treatment course, potentially misrepresenting actual delivered doses to targets and organs-at-risk (OARs). ChartCheck Adaptive, a pre- clinical automated offline adaptive solution, integrates daily cone-beam computed tomography (CBCT) imaging with deformable image registration and Monte Carlo dose recalculation on deformed planning CT scans to provide individual fraction and cumulative dose constraint monitoring. This study evaluated the feasibility and technical performance of this automated workflow for quantifying dose and volumetric variations throughout treatment courses. Material/Methods: Thirty-seven anonymized patients were retrospectively analyzed who received definitive head and neck radiotherapy with comprehensive daily CBCT imaging (median 33 fractions per patient). The ChartCheck Adaptive platform performed automated deformable image registration, structure propagation, and daily dose recalculation with cumulative dose summation. Dose constraint evaluations were performed against each patient's original clinical ClearCheck template using the RadMonteCarlo dose as baseline and volumetric structure measurements were analyzed using a default template across 40,000+ constraint assessments and structure measurements. Structures appearing in fewer than 250 fractions were excluded from analysis to ensure statistical reliability. Results: The automated workflow successfully processed all patient datasets. Volumetric analysis revealed structures with largest percentage decreases: cochlea_L (-32.5%), cochlea_R (-29.0%), constrictor_middle (-17.6%), and lips (-16.0%). Largest absolute volume decreases occurred in oral cavity (- 5.1cc), parotid_L (-3.2cc), and parotid_R (-2.8cc).OAR doses showed per fraction deviations from planned constraints. Largest mean dose increases: parotid_R
Conclusion: This pre-clinical evaluation demonstrates the technical feasibility of automated offline dose accumulation for head and neck radiotherapy using ChartCheck Adaptive. The software successfully quantified anatomical and dosimetric variations occurring during treatment courses without requiring manual intervention. The observed inter-patient variability in both volumetric changes and dose deviations suggests that individualized assessment may be valuable. Further investigation with expanded patient cohorts and correlation with clinical outcomes may help establish the clinical utility of this technology for dose- toxicity modeling and adaptive treatment decision- making. Keywords: Dose accumulation, Offline adaptive radiotherapy
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