Intra- and inter-fraction breath-hold variations and margins for radiotherapy of abdominal targets

Stefanie Ehrbar; Markus Schrader; Giulia Marvaso; Sophie Perryck; Janita E Van Timmeren; Matea Pavic; Amanda Moreira; Stephanie Tanadini-Lang; Matthias Guckenberger; Nicolaus Andratschke; Helena Garcia Schüler

doi:10.1016/j.phro.2023.100509

Intra- and inter-fraction breath-hold variations and margins for radiotherapy of abdominal targets

Phys Imaging Radiat Oncol. 2023 Nov 11:28:100509. doi: 10.1016/j.phro.2023.100509. eCollection 2023 Oct.

Affiliations

¹ Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
² Department of Radiation Oncology, European Institute of Oncology IRCSS, Milan, Italy.
³ Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy.

Abstract

Radiotherapy in expiration breath-hold (EBH) has the potential to reduce treatment volumes of abdominal targets compared to an internal target volume concept in free-breathing. The reproducibility of EBH and required safety margins were investigated to quantify this volumetric benefit. Pre- and post-treatment diaphragm position difference and the positioning variability were determined on computed tomography. Systematic and random errors for EBH position reproducibility and positioning variability were calculated, resulting in margins of 7 to 12 mm depending on the prescription isodose and fractionation. A reduced volume was shown for EBH for lesions with superior-inferior breathing motion above 4 to 8 mm.

Keywords: Abdomen; Expiration breath-hold; Margin calculation; Stereotactic body radiotherapy.