Dosimetric and radiobiological comparison of prostate VMAT plans optimized using the photon and progressive...

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• Volumetric Modulated Arc Therapy (VMAT) is a standard radiotherapy technique.
• Photon Optimization (PO) and Progressive Resolution Optimization (PRO) are inverse planning algorithms used in VMAT.
• Optimizing treatment plans is crucial for maximizing tumor control and minimizing normal tissue toxicity.

Purpose of the Study:

• To compare the dosimetric and radiobiological parameters of prostate VMAT plans optimized by PO and PRO algorithms.
• To evaluate the impact of different dose prescriptions on plan quality.
• To assess the ability of both algorithms to meet clinical dose constraints.

Main Methods:

• Retrospective analysis of 20 prostate cancer patients' VMAT plans.
• Comparison of plans generated using PO and PRO algorithms with prescriptions of 60 Gy/20 fx and 79 Gy/38 fx.
• Calculation and statistical comparison of dosimetric indices (e.g., Dmax, Dmin, Dmean, CI, HI, GI) and radiobiological parameters (TCP, NTCP, EUD).

Main Results:

• PO algorithm yielded slightly higher PTV mean dose and TCP, and better CI, HI, and GI compared to PRO.
• OARs (rectum, bladder, femur) showed slightly higher mean doses, NTCPs, and EUDs with PO optimization.
• Both PO and PRO algorithms successfully met all inverse planning dose-volume criteria and objectives.

Conclusions:

• Both PO and PRO algorithms can generate high-quality prostate VMAT plans that meet required dose-volume criteria.
• PO-optimized plans demonstrated comparable or slightly superior PTV coverage and OAR sparing to PRO-optimized plans.
• The choice between PO and PRO may depend on specific clinical priorities and desired trade-offs between target coverage and organ-at-risk doses.