title: Validation of the Mobius system for patient-specific quality assurance using introduced intentional errors.
abstract: 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.
authors.affiliation: Auckland City Hospital, Auckland, New Zealand. ivya@adhb.govt.nz.
authors.forename: Ivy Win Long
authors.initials: IW
authors.lastname: Au
authors.affiliation: Auckland City Hospital, Auckland, New Zealand.
authors.forename: Laura
authors.initials: L
authors.lastname: Ciurlionis
authors.affiliation: Auckland City Hospital, Auckland, New Zealand.
authors.forename: Neil
authors.initials: N
authors.lastname: Campbell
authors.affiliation: Auckland City Hospital, Auckland, New Zealand.
authors.forename: Daniel
authors.initials: D
authors.lastname: Goodwin
mesh_terms: D000465:Algorithms; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D011785:Quality Assurance, Health Care; D011880:Radiotherapy Planning, Computer-Assisted / Q000592:standards*
keywords: 3DVH; ArcCHECK; Gamma analysis; Introduced errors; Mobius; Patient specific QA; Treatment verification; VMAT