Reduction of clinical safety margins in proton therapy enabled by the clinical implementation of dual-energy CT for direct stopping-power prediction

• DOI: 10.1016/j.radonc.2021.11.002
• Publication Date: 2021-11-11T01:36:08Z
• Authors: Nils Peters; Patrick Wohlfahrt; Christian Hofmann; Christian Möhler; Stefan Menkel; Maria Tschiche; Mechthild Krause; Esther G.C. Troost; Wolfgang Enghardt; Christian Richter
• Keywords: Stopping power

To quantifiy the range uncertainty in proton treatment planning using dual-energy computed tomography (DECT) for a direct stopping-power prediction (DirectSPR) algorithm and its clinical implementation.To assess overall ratio (SPR) of DirectSPR implementation calibrated different patient geometries, influencing factors were categorized imaging, modeling as well others. The respective SPR was quantified lung, soft tissue bone translated into several tumor types. amount healthy spared 250 patients treated with dosimetric impact evaluated exemplarily representative brain-tumor patient.For bone, an (1σ) 1.6%, 1.3% determined DirectSPR, respectively. This allowed reduction clinically applied from currently (3.5% + 2 mm) to (1.7% (2.0% prostate-cancer patients. 150 100 benefitted sparing on average 2.6 mm 4.4 beam direction, In case, dose organs at risk close target volume achieved, mean up 16% brainstem. Patient-specific DECT-based reduced safety margins successfully introduced routine.A substantial increase accuracy achieved by patient-specific prediction. For first time, relevant imaging-based 2% level has been achieved.