Multidimensional correlation among plan complexity, quality and deliverability parameters for volumetric-modulated...

Area of Science:

• Radiation Oncology
• Medical Physics
• Statistical Analysis

Background:

• Volumetric-modulated arc therapy (VMAT) is a complex radiotherapy technique.
• Optimizing VMAT plan quality and deliverability is crucial for patient outcomes.
• Understanding the impact of complexity parameters is essential for ideal VMAT plan generation.

Purpose of the Study:

• To evaluate the impact of complexity parameters on VMAT plan quality and deliverability.
• To identify key parameters for generating ideal VMAT plans using statistical methods.
• To investigate the contribution weights of different parameters in VMAT plan optimization.

Main Methods:

• Canonical correlation analysis (CCA) was applied to assess relationships between complexity, quality, and deliverability parameters.
• The study analyzed 71 two-arc VMAT nasopharyngeal cancer (NPC) patients and 28 one-arc VMAT prostate cancer patients.
• Key parameters investigated included monitor units (MU), MU per control point (MU/CP), segment area (SA) per control point (SA/CP), and planning target volume (PTV) volume.

Main Results:

• CCA revealed significant correlations between VMAT complexity parameters and plan quality/deliverability (P = 0.047 for NPC).
• MU/CP and SA/CP were highly weighted in correlation with individual volume-based 3D gamma indices (γ(IV)).
• SA/CP, percentage of control points with SA < 5 × 5 cm2 (%SA < 5 × 5 cm2), and PTV volume strongly correlated with plan quality.

Conclusions:

• Monitor units (MU), SA-related parameters, and PTV volume significantly affect VMAT plan quality and deliverability.
• These findings aid in the generation of more optimal and deliverable VMAT plans.
• The study highlights the importance of statistical analysis in radiotherapy plan optimization.