ESTRO 2023 - Abstract Book

S788

Monday 15 May 2023

ESTRO 2023

included only specific cardiac phases (diastolic or diastolic and systolic) in combination with all respiratory phases were created. Geometric coverage (overlap of the ITV with the cardiorespiratory ITV) was calculated to evaluate these ITVs.

Results Volumes of the 17 segments were on average 6cm ³ [1-9cm ³ ] (see Figure 2). Full cardiac motion resulted in an ITV that was 83% larger than the corresponding segment volumes (ITV: 11cm ³ [2-20cm ³ ]), whereas the ITV increased by 300% compared to the segment volumes (ITV: 24cm ³ [5-38cm ³ ]) because of both cardiac and respiratory motion. The ITV incorporating only the diastolic phase and all respiratory phases had a mean coverage of 68% [52-83%] which was almost 40% smaller than the coverage of the ITV that also included the systolic cardiac phase, i.e. 96% [93-98%]. ITVs for segments located towards the free wall of the LV showed lower coverage compared to segments on the septal side.

Conclusion A framework was developed that allows assessment of motion in combination with different motion management strategies for STAR. Our results indicate that careful assessment of patient-specific motion is needed to create representative ITVs. In future research, our framework can also be used to analyze radiotherapy dose distributions for different treatment and motion management strategies to perform a full dosimetric analysis. OC-0941 STereotactic Arrhythmia Radioablation in Europe: STOPSTORM Consortium Treatment Planning Benchmark V. Trojani 1 , A. Botti 1 , M. Grehn 2 , B. Balgobind 3 , A. Savini 4 , E. Pruvot 5 , J. Verhoeff 6 , M. Iori 1 , O. Blanck 2 1 Azienda USL-IRCCS di Reggio Emilia, Medical Physics, Reggio Emilia, Italy; 2 University Medical Center of Schleswig Holstein, Radiotherapy, Kiel, Germany; 3 Amsterdam UMC, Radiotherapy, Amsterdam, The Netherlands; 4 AUSL 4 Teramo - Hospital G. Mazzini, Medical Physics, Teramo, Italy; 5 Lausanne university hospital, Heart and Vessel, Lausanne, Switzerland; 6 University Medical Center Utrecht, Radiotherapy, Utrecht, The Netherlands