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dc.contributor.authorNajem, MAen_US
dc.contributor.authorTedder, Men_US
dc.contributor.authorKing, Den_US
dc.contributor.authorBernstein, Den_US
dc.contributor.authorTrouncer, Ren_US
dc.contributor.authorMeehan, Cen_US
dc.contributor.authorBidmead, AMen_US
dc.coverage.spatialItalyen_US
dc.date.accessioned2019-06-27T11:30:17Z
dc.date.issued2018-08en_US
dc.identifierhttps://www.ncbi.nlm.nih.gov/pubmed/30139603en_US
dc.identifierS1120-1797(18)31134-7en_US
dc.identifier.citationPhys Med, 2018, 52 pp. 143 - 153en_US
dc.identifier.urihttps://repository.icr.ac.uk/handle/internal/3279
dc.identifier.eissn1724-191Xen_US
dc.identifier.doi10.1016/j.ejmp.2018.07.010en_US
dc.description.abstractWe have adapted the methodology of Berry et al. (2012) for Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) treatments at a fixed source to imager distance (SID) based on the manufacturer's through-air portal dose image prediction algorithm. In order to fix the SID a correction factor was introduced to account for the change in air gap between patient and imager. Commissioning data, collected with multiple field sizes, solid water thicknesses and air gaps, were acquired at 150 cm SID on the Varian aS1200 EPID. The method was verified using six IMRT and seven VMAT plans on up to three different phantoms. The method's sensitivity and accuracy were investigated by introducing errors. A global 3%/3 mm gamma was used to assess the differences between the predicted and measured portal dose images. The effect of a varying air gap on EPID signal was found to be significant - varying by up to 30% with field size, phantom thickness, and air gap. All IMRT plans passed the 3%/3 mm gamma criteria by more than 95% on the three phantoms. 23 of 24 arcs from the VMAT plans passed the 3%/3 mm gamma criteria by more than 95%. This method was found to be sensitive to a range of potential errors. The presented approach provides fast and accurate in-vivo EPID dosimetry for IMRT and VMAT treatments and can potentially replace many pre-treatment verifications.en_US
dc.format.extent143 - 153en_US
dc.languageengen_US
dc.language.isoengen_US
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en_US
dc.subjectAiren_US
dc.subjectAlgorithmsen_US
dc.subjectHumansen_US
dc.subjectModels, Anatomicen_US
dc.subjectPhantoms, Imagingen_US
dc.subjectRadiometryen_US
dc.subjectRadiotherapy, Intensity-Modulateden_US
dc.subjectWateren_US
dc.titleIn-vivo EPID dosimetry for IMRT and VMAT based on through-air predicted portal dose algorithm.en_US
dc.typeJournal Article
dcterms.dateAccepted2018-07-24en_US
rioxxterms.versionofrecord10.1016/j.ejmp.2018.07.010en_US
rioxxterms.licenseref.startdate2018-08en_US
rioxxterms.typeJournal Article/Reviewen_US
dc.relation.isPartOfPhys Meden_US
pubs.notesNot knownen_US
pubs.organisational-group/ICR
pubs.organisational-group/ICR/Primary Group
pubs.organisational-group/ICR/Primary Group/ICR Divisions
pubs.organisational-group/ICR/Primary Group/ICR Divisions/Radiotherapy and Imaging
pubs.organisational-group/ICR/Primary Group/ICR Divisions/Radiotherapy and Imaging/Radiotherapy Physics Modelling
pubs.publication-statusPublisheden_US
pubs.volume52en_US
pubs.embargo.termsNot knownen_US
icr.researchteamRadiotherapy Physics Modellingen_US
dc.contributor.icrauthorBernstein, Daviden_US


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