WE-G-BRCD-03: Improvement in Robustness and Delivery Efficiency of Intensity-Modulated Proton Therapy Using...

Area of Science:

• Medical Physics
• Radiation Oncology

Background:

• Intensity-modulated proton therapy (IMPT) offers precise dose delivery.
• Multi-field optimization (MFO) provides conformal doses but is sensitive to uncertainties.
• Single-field optimization (SFO) is less sensitive but may compromise plan quality.

Purpose of the Study:

• To evaluate the effectiveness of SFO with energy absorbers (EA-SFO) for IMPT in head and neck cancers.
• To compare EA-SFO plans with conventional MFO plans regarding robustness and delivery efficiency.

Main Methods:

• IMPT plans were generated using 2-field SFO with an energy absorber (EA-SFO) for four head and neck cancer patients.
• Plans were compared to existing 3-field MFO plans.
• Robustness analysis assessed dose distributions under spatial and range uncertainties.

Main Results:

• EA-SFO plans achieved clinically acceptable quality with target coverage comparable to MFO plans (within 3.5% difference in D95).
• EA-SFO plans demonstrated improved robustness, reducing plan sensitivity to uncertainties by 38.5% (targets) and 18.5% (overall).
• EA-SFO plans required 46% fewer energy layers, reducing delivery time by approximately 3 minutes.

Conclusions:

• Energy absorbers facilitate the design of robust and clinically acceptable SFO IMPT plans.
• EA-SFO improves robustness to setup and range uncertainties compared to MFO.
• EA-SFO reduces treatment delivery time and patient quality assurance (QA) time.