ESTRO 2025 - Abstract Book

S4119

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

ESTRO 2025

The upper abdomen and head and neck regions exhibited longer mean image acquisition times compared to other areas (p < 0.05). No significant difference was found for image verification and treatment delivery time. No significant reduction in total operational time was observed with an increasing number of treatment sessions, indicating that workflow efficiency remained consistent over time. Conclusion: The study highlights that while patient positioning and image acquisition are typically brief stages in proton therapy delivery, they can be prolonged in anatomical regions requiring complex positioning aids. Recognizing variations in time requirements based on anatomical regions can guide targeted workflow improvements, ultimately enhancing the efficiency of proton therapy services.

Keywords: Time analysis, proton therapy, workflow

3394

Digital Poster Use of a compression belt as a cost-effective means for reducing lung tumour motion for SBRT treatment Danny Schuring, Brenda van Stijn, Caroline Tissing-Tan, Eva Bongers Department of Radiation Oncology, Radiotherapiegroep, Arnhem/Deventer, Netherlands Purpose/Objective: A compression belt is successfully used for breathing motion reduction of abdominal tumours on our MR-linac. This belt is tightened around the abdominal region of the patient. As this is a low-cost, easily applicable means of reducing breathing motion, the purpose of this study was to investigate whether this could also be applied to reduce the motion of lung tumours. Material/Methods: For patients suitable for SBRT with lung tumours in the lower lobe, a 4D-CT was acquired both with and without abdominal compression. A compression belt (Reversa® Vario Promaster, Thuasne, France [1]) was used (figure 1). This belt can be tightened around the patient’s waist using velcro fasteners; markings were added so it can be tightened reproducibly. The 4D-CT was reconstructed in ten phases, after which the tumour was delineated on the 0% phase, and mapped to the other phases using DIR. Breathing motion was determined from the center-of-mass of the tumour delineation on all phases, and the peak-to-peak amplitude (PtP) was recorded in the AP, lateral and SI direction for both scans. When a significant motion reduction was observed were subsequently treated with the belt in all fractions.