ESTRO 2024 - Abstract Book

S766

Clinical - CNS

ESTRO 2024

For treatments targeting areas below the T4, we typically apply 4 VMAT posterior arcs ranging between 90° – 180° and 180° – 270°. However, for the C and upper T spine regions, the arc limitations might expand to ensure maximal protection of healthy tissues. Post-simulation, a detailed document, inclusive of the pertinent settings and photographs, is incorporated into the patient's electronic medical records for reference during the actual treatment. The physicians delineate the gross tumor volume (GTV) using MR images, capturing both the epidural and paraspinal aspects (cox paper). The clinical target volume (CTV) is created by expanding the GTV to anticipate subclinical spread within the bone. Treatment planning is performed with Raystation version 12A. To improve consistency and efficiency, a script is used to generate planning structures, objectives, and goals tailored to meet the unique needs of each patient. To guide treatments, our imaging regimen integrates a sequence of modalities (Figure 3). Initially, the patient is aligned with the Brainlab ExacTrac (ET) system. ExacTrac serves as an independent IGRT system from the linac, delivering kV images combined with infrared surveillance. Next, patient alignment is confirmed with CBCT. With concordance between the two systems established, we rely solely on real-time ET imaging during treatment. A kV and MV imaging pair is acquired before treatment initiation as a final verification.

Results: