Improving efficiency in lung SAbR planning using integrated tools for X-ray based adaptive radiotherapy.

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• Online adaptive radiotherapy (ART) for lung stereotactic ablative radiotherapy (SAbR) offers improved precision.
• Transitioning existing SAbR planning templates between radiotherapy systems requires evaluation.
• Ethos2.0 introduces new features for dose fall-off and automated beam arrangement.

Purpose of the Study:

• To assess the feasibility of translating lung SAbR treatment plans from Ethos1.1 to Ethos2.0.
• To leverage Ethos2.0's new features for enhanced dose fall-off and automated beam arrangement.
• To streamline SAbR planning and support broader ART adoption.

Main Methods:

• Fifteen Ethos1.1 lung SAbR plans were reoptimized in Ethos2.0 using identical parameters.
• Evaluated high-fidelity (HF) mode with and without automatic treatment geometry selection (HF-cIMRT, HF-aIMRT/VMAT).
• Compared plan quality and efficiency using RTOG metrics and plan deliverability analysis.

Main Results:

• Ethos2.0 reoptimized plans showed acceptable quality with no significant differences in organ-at-risk doses.
• Human-selected beam geometry was superior for complex cases compared to automated selection.
• HF-enabled plans significantly reduced monitor units, though conformity index showed minor trade-offs.

Conclusions:

• Lung SAbR planning is effectively transferable from Ethos1.1 to Ethos2.0, enhancing workflow efficiency.
• Automated beam geometry tools improve planner efficiency for intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT).
• Integrated automation is crucial for managing increased ART workload and staffing demands.