SBRT of ventricular tachycardia using 4pi optimized trajectories

Area of Science:

• Radiation Oncology
• Medical Physics
• Cardiac Ablation

Background:

• Stereotactic body radiation therapy (SBRT) is an emerging treatment for ventricular tachycardia (VT).
• Optimizing radiation delivery to minimize dose to organs at risk (OARs) is crucial in VT-SBRT.
• Conventional arc trajectories may lead to suboptimal dose distribution.

Purpose of the Study:

• To evaluate the dosimetric benefits of 4pi-optimized arc trajectories in VT-SBRT.
• To compare radiation dose to OARs using conventional versus 4pi-optimized plans.
• To assess the potential for improved healthy tissue sparing in VT-SBRT.

Main Methods:

• Retrospective analysis of 15 patient datasets for VT-SBRT.
• Contouring of OARs and planning target volumes (PTVs) based on CT data.
• Comparison of a conventional two-arc plan with a 4pi-optimized plan using a dose-sparing algorithm.
• Dosimetric analysis of maximum, mean, and median doses to OARs and PTVs.

Main Results:

• Significant reductions in maximum, mean, and median doses to various OARs including the esophagus, spinal cord, and trachea.
• Substantial decrease in mean and median doses to cardiac structures and other thoracic organs.
• No significant difference in PTV maximum dose or homogeneity index.
• Conformity number was slightly lower for 4pi-optimized plans.

Conclusions:

• 4pi-optimized trajectories significantly reduce radiation dose to non-cardiac OARs in VT-SBRT.
• The technique effectively spares cardiac structures from high radiation doses.
• 4pi-optimized trajectories represent a promising advancement for VT-SBRT, enhancing treatment safety.