PD-0862 Automatic PTV margin determination for midposition-based lung SBRT planning on the Unity MRlinac

摘要: For midposition (midpos) based dose planning, a patient-specific PTV margin is typically determined by measuring the peak-to-peak (p2p) motion of the GTV during the breathing cycle. Our goal is to develop a new method to determine the PTV margin automatically for lung SBRT midpos-planning on the Unity MR-linac (Elekta AB, Stockholm, SE). Robustness of the automatic, patient-specific margin expansion is demonstrated using 4D dose accumulation.