ESTRO 2022 - Abstract Book

S1509

Abstract book

ESTRO 2022

Conclusion We observed clear dosimetric variations depending on the gating method, which was reproducible between film measurements and simulations. In the future, our model will be applied to clinical tracking data to prospectively assess patient-specific PTV margins. Such simulations may be necessary to ensure accurate dose delivery in challenging cases on the MR linac.

PO-1710 Robustness evaluation of surface guided DIBH breast radiotherapy

A. Gnerucci 1 , S. Russo 2 , M. Esposito 2 , A. Ghirelli 2 , S. Pini 2 , L. Paoletti 3 , R. Barca 3 , S. Fondelli 3 , P. Alpi 3 , B. Grilli 3 , F. Rossi 4 , S. Scoccianti 3 1 University of Florence, Physics and Astronomy, Florence, Italy; 2 Azienda USL Toscana Centro, Medical Physics Unit, Florence, Italy; 3 Azienda USL Toscana Centro, Radiotherapy Unit, Florence, Italy; 4 Azienda USL Toscana Sud Est, Radiotherapy Unit, Grosseto, Italy Purpose or Objective Aim of this work was to assess the robustness of a DIBH technique based on optical surface tracking technology for patients undergoing adjuvant RT for left sided breast cancer. Materials and Methods Ten patients were enrolled in this study. 3D conformal technique for 42,56Gy dose in 16 fractions was adopted. C-RAD Sentinel™ laser scanning system and a Siemens CT scanner were used for the prospective DIBH CT study. Base line and gating window levels (5mm amplitude) were established during CT simulation procedure. Gated treatments delivery was supported by the C-RAD Catalyst™ system connected with an Elekta Synergy. Residual isocenter shifts were tracked in real time by matching the live surface with a daily reference with a threshold for beam triggering set to 5 mm.