Online adaptive MRgRT time fell from 67 to 48 minutes over eight years

KEY POINTS

• This retrospective single-institution analysis covered 1026 patients, 1203 treatment courses and 7665 fractions delivered on a 0.35-T MR-Linac between April 2018 and April 2026. Pancreatic tumors were the largest group (35.7% of courses); the median prescription was 50 Gy in five fractions.
• Treatment complexity increased markedly between 2018–2022 and 2022–2026: SBRT use rose from 49.9% to 81.1% of fractions, online adaptation from 32.9% to 80.2%, breath-hold/gating from 75.9% to 88.8%, and elective coverage from 61.8% to 78.2%. Pancreatic treatments and single-fraction courses also became more common.
• Despite this shift, median total in-room time for online-adaptive fractions fell from 67 to 48 minutes, a 28.4% reduction (p<0.001). The largest contributor was adaptive workflow time, which decreased from 20 to 7 minutes, a 65% reduction, while setup time fell from 28 to 23 minutes.
• The percentage of adaptive fractions completed within one hour increased from 35.5% to 78.1%. Completion within 50 minutes increased from 13.0% to 57.2%, and within 45 minutes from 5.5% to 40.7%.
• Pancreatic adaptive treatments showed particularly large gains: annual median in-room time declined from 85 to 45 minutes, while non-pancreatic adaptive fractions decreased from 75 to 50 minutes. By contrast, non-adaptive treatment time remained essentially unchanged at 35 versus 34 minutes (p=0.447).
• Efficiency gains coincided with staff experience and a major 2022 system upgrade enabling faster optimization, fewer workflow pauses and parallel team tasks. Because timestamps were manually recorded, technology and learning effects could not be separated, case mix changed over time, and the study did not evaluate dosimetric quality or clinical outcomes.

CLINICAL TAKEAWAY

SOURCE

Cancers