title: Evaluation of Intensity Modulated Radiation Therapy Delivery System using a Volumetric Phantom on the Basis of the Task Group 119 Report of American Association of Physicists in Medicine.
abstract: The current work describes the implementation of the American Association of Physicists in Medicine (AAPM)'s Task Group 119 report on a volumetric phantom (Delta4, Scandidos, Uppsala, Sweden) following the stated dose goals, to evaluate the step-and-shoot intensity modulated radiation therapy (IMRT) system. Delta4consists of diode detectors, lying on two crossed planes, measuring the delivered dose, and providing two-dimensional dosimetric information. Seven plans of different goals and complexity were performed, with individual structure sets. TG199 structure sets and plans were transferred and implemented on the Delta4phantom taking into account its cylindrical geometry. All plans were delivered with a 6 MV linear accelerator equipped with multileaf collimator of 1 cm thickness. Plan results for each test met the recommended dose goals. The evaluation was performed in terms of dose deviation, distance to agreement, and gamma index passing rate. In all test cases, the gamma index passing rate was measured >90%. Delta4phantom has proven to be fast, applicable, and reliable for the step-and-shoot IMRT commissioning following TG119's recommended tests. Although AAPM's TG119 report is referring to the implementation of test plans that do not correspond to patient plans, it could be used as an evaluation tool of various IMRT systems, considering the local treatment planning system and the delivery system.
authors.affiliation: Department of Radiology, Medical Physics Unit, Aretaieion Hospital, University of Athens, Greece.
authors.forename: Raphaela
authors.initials: R
authors.lastname: Avgousti
authors.affiliation: Department of Radiology, Medical Physics Unit, Aretaieion Hospital, University of Athens, Greece.
authors.forename: Christina
authors.initials: C
authors.lastname: Armpilia
authors.affiliation: Department of Radiotherapy Physics, Nottingham University Hospital, NHS Trust, Nottingham, United Kingdom.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Floros
authors.affiliation: Department of Radiology, Medical Physics Unit, Aretaieion Hospital, University of Athens, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Antypas
keywords: Commissioning; intensity modulated radiation therapy; quality assurance; volumetric phantom