title: RapidArc quality assurance through MapCHECK.
abstract: The purpose is to devise a patient-specific quality assurance procedure for RapidArc radiotherapy using the MapCHECK detector array. We use our existing MapCHECK system and a Solid Water phantom with an embedded ion chamber to develop a quality assurance procedure for RapidArc treatment after commissioning. The ion chamber used to measure the absolute dose is surrounded by 6 cm layers of solid water on the anterior and posterior sides. Partial arcs derived from the treatment planning system were used with MapCHECK to determine the actual shape of the dose and correct for the angular dependence. The ion chamber measurements were within 1% of the absolute doses predicted by the Eclipse treatment system. When using a partial arc from 60° to 300° on the MapCHECK array (gamma index <1: 3%, 3 mm, 10% threshold), we obtain a 97.52% average passing rate. A combination of ion chamber phantoms, partial arcs and the MapCHECK system can be used for quality assurance of RapidArc therapies.
authors.affiliation: Radiation Oncology, St Vincent Hospital, Green Bay, Wisconsin 54307, USA. agloi@stvgb.org
authors.forename: Aime M
authors.initials: AM
authors.lastname: Gloi
authors.forename: Robert E
authors.initials: RE
authors.lastname: Buchana
authors.forename: Corrie L
authors.initials: CL
authors.lastname: Zuge
authors.forename: AnnDrea M
authors.initials: AM
authors.lastname: Goettler
mesh_terms: D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D005260:Female; D006801:Humans; D007477:Ions; D008297:Male; D010388:Pelvis / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy; D011786:Quality Control; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D007477:Ions