Performance assessment of a new optimization system for robotic SBRT MLC-based plans

Area of Science:

• Medical Physics
• Radiation Oncology
• Medical Imaging

Background:

• Stereotactic Body Radiation Therapy (SBRT) requires precise radiation delivery.
• CyberKnife with Multi-Leaf Collimator (MLC) is used for SBRT.
• Optimization of treatment plans is crucial for SBRT efficacy and safety.

Purpose of the Study:

• To evaluate the performance of the new VOLO optimization system for CyberKnife MLC-based SBRT plans.
• To compare VOLO with the existing Sequential optimizer in terms of plan quality and efficiency.
• To assess the clinical utility of the VOLO system.

Main Methods:

• MLC-based SBRT plans were generated for 25 diverse cases using both VOLO and Sequential optimizers.
• Plan quality was assessed using metrics like monitor units (MU), delivery time (DT), PTV coverage, conformity (nCI), and OAR doses.
• A mathematical score (MS) combined these metrics, with validation through parameter weighting and blinded clinical evaluation.

Main Results:

• VOLO significantly reduced mean delivery time (-19%) and monitor units (-13%) compared to Sequential.
• Optimization times (OT) for VOLO were under 15 minutes, drastically shorter than Sequential (8-160 minutes).
• VOLO plans achieved higher mathematical scores, with comparable PTV coverage and OAR sparing; physicians preferred VOLO in 80% of cases.

Conclusions:

• The VOLO optimization system demonstrates superior performance in CyberKnife SBRT planning.
• VOLO significantly enhances planning and delivery efficiency due to reduced optimization times and monitor units.
• The study proposes a robust methodology for comparing radiation therapy planning solutions.