Beyond Gamma Analysis: An Accessibility-oriented Framework for Comparative Evaluation of Patient-specific Radiotherapy Quality Assurance
Vikram, Raj Pal Singh, Manindra BhushanAbstract
Background:
Patient-specific quality assurance (QA) in radiotherapy is traditionally performed using measurement-based systems that require dedicated hardware, machine time, and manpower. Although software-based QA approaches have emerged as efficient alternatives, their comparative accessibility and operational performance remain insufficiently investigated. This study evaluated conventional and software-based QA methodologies using integrated dosimetric, temporal, and economic metrics.
Materials and Methods:
A total of 90 clinically approved treatment plans, including head-and-neck, pelvis, and lung volumetric modulated arc therapy/stereotactic body radiotherapy cases, were retrospectively analysed. All plans were generated in Eclipse TPS v15.6 and evaluated using ArcCHECK phantom-based QA, electronic portal imaging device (EPID)-based QA, and log file-based QA. Gamma analysis was performed using 3%/2 mm criteria with a 10% dose threshold. Workflow time and relative cost burden were recorded for each method. Three composite indices were defined: QA Cost Efficiency Index (QCEI), QA Efficiency Index (QEI), and QA Accessibility Index (QAI). Statistical comparisons were performed using paired analysis with Bonferroni correction.
Results:
All QA methods achieved clinically acceptable gamma passing rates. Log file-based QA demonstrated the highest median gamma passing rate; however, the absolute differences between methodologies were small, and all approaches exceeded the predefined clinical acceptance criterion (≥95%). ArcCHECK showed the greatest workflow time and cost burden, whereas log file-based QA demonstrated the highest QCEI, QEI, and QAI values. EPID-based QA showed intermediate performance. All pairwise differences in accessibility metrics were statistically significant (
Conclusion:
Software-based QA approaches significantly improved operational efficiency and accessibility while maintaining clinically acceptable dosimetric agreement. However, further prospective, multi-institutional validation of the proposed accessibility framework is warranted.