Author: Tae Kyu Lee 👨🔬
Affiliation: Allina Health 🌍
Purpose: To assess the feasibility of a dynamic-platform integrated with high-resolution patient-specific-quality-assurance (PSQ device for periodic quality assurance (PQA) and PSQA in respiratory-gated Lung SBRT procedure, and in this study 30-70% phase gating window was used. The study benchmarked QA performance across respiratory patterns, including Cos⁴ waveforms for PQA and real-patient (RPT) breathing patterns for PSQA, comparing them to non-gated reference QA measurements.
Methods: The StereoPHAN and SRS MapCheck were mounted on dynamic-platform to introduce motion using Cos4 and RPT breathing patterns. The analysis involved comparisons of Gamma index passing rates, maximum dose differences, and central axis (CAX) dose differences between measurements and treatment planning system (TPS) calculations using the Analytical Anisotropic Algorithm (AAA) and Acuros. Gamma index evaluations used 2.0 mm/2.0% criteria for AAA, and 2.0 mm/2.0% and 2.0 mm/3.0% criteria for Acuros. Statistical analyses assessed the significance of differences, with p-values calculated for Gamma index passing rates under various conditions.
Results: Most gated scenarios achieved Gamma pass rates exceeding 95% under clinical criteria. Significant differences (p < 0.05) were observed between gated and non-gated setups, particularly for RPT scenarios using AAA at 2.0 mm/2.0% criteria. Statistical analyses of maximum dose differences (p-values: 0.164–0.483) indicated meaningful trends, though not all were significant. CAX dose differences exhibited trends nearing significance, with p-values as low as 0.095, highlighting the potential advantages of gated QA setups. Planar dose profiles demonstrated strong agreement between measured and planned doses, with minimal spatial deviations.
Conclusion: The integration of high-resolution PSQA device with a dynamic-platform is a feasible and effective approach for PQA and PSQA in respiratory-gated Lung SBRT procedure. Statistically significant differences observed in RPT scenarios using AAA underscore the importance of accurate dose calculation algorithms for PSQA. These findings provide a reliable framework for QA processes and underscore the potential for optimizing gated treatments.