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Validation of the Mobius system for patient-specific quality assurance using introduced intentional errors


Mobius3D and MobiusFX are model-based verification tools for treatment plan dose calculation and treatment delivery. The software facilitates patient-specific quality assurance by extracting data from linear accelerator treatment log files and performing a 3D dose calculation on the original patient CT dataset using an independent collapsed cone algorithm. In this study, we evaluate the ability of the Mobius system to detect linear accelerator-related errors compared with existing measurement-based systems, namely the ArcCHECK® and 3DVH® systems. Three original treatment plans and 47 plans with introduced delivery errors, for a total of 50 plan deliveries, were investigated. The results from this study demonstrated comparable gamma passing rates and error detectability between the Mobius and ArcCHECK® systems while the 3DVH system generally exhibited a lower sensitivity. This work also demonstrated the ability of the Mobius system to detect delivery errors of down to 2° collimator rotation, 1 mm MLC bank offset and 10 mm collimator jaw offset.

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Correspondence to Ivy Win Long Au.

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Au, I.W.L., Ciurlionis, L., Campbell, N. et al. Validation of the Mobius system for patient-specific quality assurance using introduced intentional errors. Australas Phys Eng Sci Med 40, 181–189 (2017).

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  • Patient specific QA
  • Treatment verification
  • VMAT
  • Gamma analysis
  • Introduced errors
  • Mobius
  • ArcCHECK
  • 3DVH