ESTRO 2024 - Abstract Book

S4515

Physics - Machine learning models and clinical applications

ESTRO 2024

Results:

In Figure 1 we illustrate the contour sensitivity envelopes for two patients on a sagittal and axial slice. The PF of these patients is more sensitive to contour adjustments of the anterior part of the rectum closest to the PTV (A ↓ ) with an envelope for both patients of around 1 mm in those sections to ensure dose deviations <0.5 Gy. On the other hand, posterior the envelope ranges over 8-10mm. The relative large inferior section for patient B probably results in less tolerance of this section to contractions 10mm vs 3mm for patient A. Discontinuities are due to the course subdivision in 10 sections. The calculation times of the personalized-envelopes were 10-30 seconds per patient depending on the volume of rectum and PTV. Figure 2 shows a boxplot summarizing the results for all 110 patients and regions considered. For all regions sensitivity to contractions is lower than to expansions. Sensitivity is similar for L/R reflecting the symmetry in the geometry. For P, L, R sensitivity is low for all patients and often larger than the 10mm maximal perturbations considered here. Anterior and superior sections of the rectum are most sensitive with median sensitivity envelope of around 1 mm.