title: The quality assurance of volumetric modulated arc therapy (VMAT) plans for early stage prostate cancer: a technical note.
abstract: As radiation therapy transitions from intensity modulated radiation therapy (IMRT) to volumetric modulated arc therapy (VMAT) it is important to consider the quality assurance (QA) of VMAT plans in light of what has previously been learned and developed in IMRT QA. This technical note assesses if IMRT based plan QA software, which has reduced the need in IMRT for phantom dose measurements on the linear accelerator, can be incorporated into VMAT QA processes. Twenty prostate cases were retrospectively planned using VMAT with one arc to deliver a prescription of 74 Gy in 37 fractions. A plan QA was performed using bothIMSure(version 3.3), a software-based IMRT QA program, andArcCHECK(version 6.2.3.5713), a phantom-based VMAT QA tool. Outcomes assessed included the time needed to perform the QA of both theIMSureandArcCHECKQA methods, and agreement between planned dose and QA measured dose. On average per case, theArcCHECKtechnique needed 31.5 min to perform the VMAT plan QA, whileIMSurerequired 3.5 min to perform the same QA. All 20 cases passed dosimetric QA usingArcCHECK. However, usingIMSure, three cases failed dosimetric QA using the departments existing IMRT QA criteria. This research has demonstrated that the IMRT QA softwareIMSuremay be incorporated into the QA of VMAT plans, however the criteria to assess the dosimetry of the VMAT plans may need to be different to that for IMRT cases. The implication of this research for radiation therapists is to be critically aware of the differences between the plan QA requirements and methods for IMRT and those required for VMAT.
authors.affiliation: British Columbia Cancer Agency, Fraser Valley Centre Surrey, British Columbia, Canada ; School of Health Sciences, University of Newcastle Callaghan, New South Wales, Australia.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Elith
authors.affiliation: School of Health Sciences, University of Newcastle Callaghan, New South Wales, Australia.
authors.forename: Shane E
authors.initials: SE
authors.lastname: Dempsey
authors.affiliation: British Columbia Cancer Agency, Fraser Valley Centre Surrey, British Columbia, Canada.
authors.forename: Fred
authors.initials: F
authors.lastname: Cao
authors.affiliation: British Columbia Cancer Agency, Fraser Valley Centre Surrey, British Columbia, Canada.
authors.forename: Afrooz
authors.initials: A
authors.lastname: Farshadi
authors.affiliation: School of Health Sciences, University of Newcastle Callaghan, New South Wales, Australia.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Warren-Forward
keywords: ArcCHECK; IMSure; VMAT; quality assurance