Leveraging High-Fidelity Mode for Improved Online Adaptive Stereotactic Accelerated Partial Breast Treatment...

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Background:

• Online adaptive radiation therapy (OART) using cone beam computed tomography (CBCT) for stereotactic accelerated partial breast irradiation (APBI) addresses lumpectomy bed variations.
• However, OART's daily reoptimization prolongs treatment, potentially increasing patient discomfort and intrafraction variations.

Purpose of the Study:

• To investigate the feasibility of using the high-fidelity (HF) mode in stereotactic radiation therapy for APBI OART.
• To analyze the impact of HF mode on optimization time and plan quality through an in silico study.

Main Methods:

• A retrospective in silico study analyzed 25 patient datasets, with 10 used for tuning an HF planning strategy.
• Five OART fractions were emulated for 15 patients using virtual planning software, comparing HF and non-HF templates.
• Dose-volume histogram metrics, optimization times, and quality assurance results were analyzed.

Main Results:

• HF adaptive planning showed minor improvements in breast V100%/50% and Ribs D0.01cc, with marginally inferior PTV V100% and lung V30% compared to non-HF.
• Median online optimization time was reduced by 54% (5.4 minutes) per fraction with HF mode.
• Patient-specific quality assurance showed no significant difference in delivery accuracy (gamma passing rate >97% for both).

Conclusions:

• Leveraging Ethos v2.0 HF mode can significantly enhance treatment efficiency for volumetric modulated arc therapy APBI.
• A >50% reduction in optimization time was observed, maintaining plan quality in a nonclinical setting.
• This approach may reduce patient discomfort and mitigate intrafraction variations in APBI OART.