Potential margin reduction in prostate cancer proton therapy with prompt gamma imaging for online treatment verification

Stefanie Bertschi; Kristin Stützer; Jonathan Berthold; Julian Pietsch; Julien Smeets; Guillaume Janssens; Christian Richter

doi:10.1016/j.phro.2023.100447

Potential margin reduction in prostate cancer proton therapy with prompt gamma imaging for online treatment verification

Phys Imaging Radiat Oncol. 2023 May 15:26:100447. doi: 10.1016/j.phro.2023.100447. eCollection 2023 Apr.

Authors

Stefanie Bertschi¹, Kristin Stützer¹, Jonathan Berthold^{1

2}, Julian Pietsch^{1

2}, Julien Smeets³, Guillaume Janssens³, Christian Richter^{1

2

4

5}

Affiliations

¹ OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Fetscherstr. 74, PF41, 01307 Dresden, Germany.
² Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Bautzner Landstr. 400, 01328 Dresden, Germany.
³ Ion Beam Applications SA, Chemin du Cyclotron 3, 1348 Louvain-la-Neuve, Belgium.
⁴ German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69192 Heidelberg, Germany.
⁵ Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, PF 50, 01307 Dresden, Germany.

Abstract

The potential of proton therapy is currently limited due to large safety margins. We estimated the potential reduction of clinical margins when using prompt gamma imaging (PGI) for online treatment verification of prostate cancer. For two adaptive scenarios a potential reduction relative to clinical practice was evaluated. The use of a trolley-mounted PGI system for online treatment verification to trigger an adaptation reduced the current range margins from 7 mm to 3 mm. In a case example, the dose reduction due to reduced range margins was substantially larger compared to reduced setup margins when using pre-treatment volumetric imaging.

Keywords: Margin reduction; Prompt gamma imaging; Prostate cancer; Proton therapy; Range verification.