Improving DIBH-PBS treatment for NSCLC: reducing delivery time with advanced spot reduction techniques

Area of Science:

• Medical Physics
• Radiation Oncology
• Proton Therapy

Background:

• Breath-hold (BH) proton therapy is crucial for treating moving targets, but prolonged irradiation times necessitate multiple BHs.
• Treatment delivery time in pencil beam scanning is influenced by beam-on time and dead time (energy/spot adjustments).

Purpose of the Study:

• To investigate how spot-reduction techniques affect proton therapy delivery time, robustness, and plan quality for moving targets.
• To optimize breath-hold proton therapy for non-small cell lung cancer patients.

Main Methods:

• Treatment plans were created for 12 lung cancer patients using a range modulator (RM) and various spot placement algorithms (SPAs).
• SPAs included fixed grid, energy-dependent grid, and two optimization types: conventional and spot suppression (SS).

Main Results:

• The combination of RM and a fixed grid SPA yielded the best plan quality and robustness.
• All tested SPAs similarly reduced treatment time.
• Spot suppression optimization reduced spot count but did not decrease overall treatment time.

Conclusions:

• A fixed grid spot placement algorithm combined with a range modulator offers an efficient method for high-quality breath-hold proton therapy.
• This approach can significantly reduce irradiation time, enhancing the clinical feasibility of BH proton therapy for moving targets.