Clinical implementation considerations for proton dose-driven continuous scanning: comparative analysis of breakpoint...

Area of Science:

• Medical Physics
• Radiation Oncology

Background:

• Proton dose-driven continuous scanning (DDCS) offers potential for improved treatment efficiency.
• Optimizing breakpoint (BP) strategies and scan path is crucial for effective DDCS implementation.

Purpose of the Study:

• To evaluate different breakpoint strategies and scan path optimization impacts on dose accuracy, beam interruptions, and delivery efficiency in DDCS.
• To provide insights for clinical implementation of DDCS, balancing key treatment parameters.

Main Methods:

• Retrospective simulation of proton pencil beam scanning plans for DDCS.
• Evaluation of five BP strategies (three spot distance-based, two scan ratio-based) with beam current optimized for shortest beam delivery time (BDT).
• Analysis of three scan paths (default, length-optimized, time-optimized) assessing BP fraction, dose accuracy (Gamma, DVH RMSE), and BDT.

Main Results:

• Spot distance-based strategies (especially SD2 with length-optimized path) achieved excellent dose accuracy (>98% Gamma, <1% DVH RMSE) and minimized beam interruptions (median 1.1%).
• Scan ratio-based approaches (especially SR0 with time-optimized path) achieved shorter BDTs while maintaining acceptable dose accuracy (>95% Gamma, <2% DVH RMSE).
• Scan path optimization reduced beam interruptions for SD-based methods and improved dose accuracy for SR-based methods.

Conclusions:

• Dose accuracy in DDCS is achievable without compromising beam current optimized for BDT.
• SD2 with length-optimized path is preferred for minimizing dose deviations and beam interruptions.
• SR0 with time-optimized path is suitable when shorter BDT is critical, offering complementary strengths for DDCS implementation.