KEY POINTS
- This technical commissioning study developed a reusable end-to-end test for simulation-omitted direct-to-unit adaptive radiotherapy using a commercially available CIRS ZEUS phantom, digitally deformed pre-planning datasets, ionization chambers, and radiochromic film.
- The workflow was evaluated on two adaptive platforms: cone-beam computed tomography-guided Ethos and magnetic resonance-guided Elekta Unity. Each system delivered six adaptive fractions, testing both minor and large discrepancies between the pre-planning and treatment geometries.
- All target and organ-at-risk point-dose measurements agreed with treatment-planning-system calculations within 3% for high-dose measurements or 3 cGy for low-dose measurements.
- All eight planar film measurements achieved gamma pass rates above 90% at 3%/3 mm and above 98% at 5%/3 mm, exceeding the referenced IROC acceptance benchmark of 85% at 7%/4 mm.
- End-to-end testing identified clinically relevant workflow vulnerabilities, including cone-beam computed tomography truncation, suboptimal isocentre positioning, and unsuitable pre-plan beam arrangements. No patient outcomes or clinical safety endpoints were evaluated.
CLINICAL TAKEAWAY
The proposed framework offers an accessible way to commission the complete diagnostic-image-to-adaptive-delivery pathway before introducing simulation-omitted treatment clinically. The results are technically encouraging across two platforms, but they come from one institution, one phantom configuration, and a limited number of measurements, so this is a practical commissioning method rather than a validated universal standard.
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