ESTRO 2025 - Abstract Book

S4047

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2025

Figure 1: Intrafraction motion measurements.

Lateral (x) movement showed the most dispersion, with the highest number of outliers (figure 2). The mean deviations were 0.03 mm (x), 0.06 mm (y), and -0.20 mm (z), all under 1 mm, indicating minimal systematic error. Absolute mean deviations were 1.01 mm (x), 1.15 mm (y), and 0.97 mm (z).

Figure 2: Dispersion in the 3 axis

Conclusion: The findings validate current SBRT protocols for pancreatic cancer, confirming that the established PTV margins effectively account for most intrafraction motion, ensuring precise targeting while protecting nearby organs. Abdominal compression remains an effective method to enhance SBRT accuracy in clinical practice.

Keywords: Motion management, pancreatic cancer, SBRT