Analyzing Cardiorespiratory Motion and Its Dosimetric Effect on Stereotactic Arrhythmia Radio-Ablation: A...

Area of Science:

• Medical Physics
• Radiotherapy Oncology
• Cardiac Electrophysiology

Background:

• Stereotactic arrhythmia radio-ablation (STAR) is an emerging treatment for refractory ventricular tachycardia.
• Understanding cardiorespiratory motion's impact on STAR is crucial for treatment efficacy and safety.
• The STOPSTORM.eu registry provides multicenter data to investigate these effects.

Purpose of the Study:

• To quantify cardiorespiratory motion during STAR procedures.
• To assess the dosimetric consequences of this motion across different treatment techniques.
• To compare motion estimation methods, including deformable image registration and auto-contouring.

Main Methods:

• Collected data from 61 ventricular tachycardia patients undergoing STAR.
• Utilized various treatment approaches: free-breathing with internal target volume (FB:ITV), free-breathing with respiratory tracking (FB:TR), abdominal compression (AC), and deep inspiration breath-hold (BH).
• Estimated motion using deformable image registration and auto-contoured structures; calculated motion-adjusted dose distributions and conformity indices.

Main Results:

• Median planning target volume motion ranged from 4.9 mm (BH) to 6.0 mm (FB).
• The left ventricle exhibited the highest motion (median 95th percentile: 5.5-6.8 mm).
• Conformity index reductions due to motion varied by technique, with FB:TR showing the least impact (-1.3%).
• Mean and maximum doses to organs at risk increased, particularly for small structures.

Conclusions:

• Cardiorespiratory motion and its dosimetric impact are significant in STAR for ventricular tachycardia.
• Motion estimation consistency was observed between deformable image registration and auto-contouring.
• Respiratory tracking emerged as the most effective method for mitigating the dosimetric impact of motion.