ESTRO 2024 - Abstract Book

S5589

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

ESTRO 2024

Keywords: Planning MRI, IGRT, sCT

References:

1) Chandarana, H., Wang, H., Tijssen, R. H. N., & Das, I. J. (2018). Emerging role of MRI in radiation therapy. Journal of magnetic resonance imaging : JMRI, 48(6), 1468–1478. https://doi.org/10.1002/jmri.26271

2) Wyatt, J. J., Brooks, R. L., Ainslie, D., Wilkins, E., Raven, E., Pilling, K., Pearson, R. A., & McCallum, H. M. (2019). The accuracy of Magnetic Resonance - Cone Beam Computed Tomography soft-tissue matching for prostate radiotherapy. Physics and imaging in radiation oncology, 12, 49–55. https://doi.org/10.1016/j.phro.2019.11.005 3) White paper MR-based Synthetic CT reimagined An AI-based algorithm for continuous Hounsfield units in the pelvis and brain – with syngo.via RT Image Suite (VB60) siemens-healthineers.com/radiotherapy Michaela Hoesl, PhD Nuria Escobar Corral, PhD Nilesh Mistry, PhD

2647

Digital Poster

Setup of SRS treatment with open-face mask using Surface Guided Radiotherapy and head adjuster

Marlon van den Broek, Mieke Heldens- van Rooy, Martijn Kusters

Radboud University Medical Center, Radiotherapy, Nijmegen, Netherlands

Purpose/Objective:

In April 2023 our clinic started treatment of patients with intracranial tumors using SGRT system AlignRT (VisionRT Inc, UK) and head adjuster (VisionRT Inc, UK) and open-face masks (Orfit, Belgium). PTV margins are 2 mm and rotations of the head of the patient are corrected with the head adjuster, which make it possible to treat multiple PTVs with a single isocenter.

Material/Methods:

This study shows the results of the first ten patients (total of 22 fractions) treated with this new workflow compared to seven patients (27 fractions) with old clinical workflow. Patients with single or multiple intracranial tumors with fractionation schedules of 3x8 Gy, 1x16 Gy or 1x21 Gy were included. In previous workflow patients had a planning CT and treatment in closed face mask. Treatment plans were generated with separate isocenters for each PTV. During treatment a fixed table which only allows translations was used. Before radiation two Cone beam Computer Tomography (CBCT) scans per isocenter were made (one to correct translations, one for correction control) with a tolerance of 1mm translations and 3 degree on rotations.