title: Quantitative Verification of Dynamic Wedge Dose Distribution Using a 2D Ionization Chamber Array.
abstract: The accuracy of two calculation algorithms of the Eclipse 8.9 treatment planning system (TPS)--the anisotropic analytic algorithm (AAA) and pencil-beam convolution (PBC)--in modeling the enhanced dynamic wedge (EDW) was investigated. Measurements were carried out for 6 and 18 MV photon beams using a 2D ionization chamber array. Accuracy of the TPS was evaluated using a gamma index analysis with the following acceptance criteria for dose differences (DD) and distance to agreement (DTA): 3%/3 mm and 2%/2 mm. The TPS models the dose distribution accurately except for 20×20 cm(2) field size, 60 (°) and 45 (°) wedge angles using PBC at 6 MV photon energy. For these latter fields, the pass rate and the mean value of gamma were less than 90% and more than 0.5, respectively at the (3%/3 mm) acceptance criteria. In addition, an accuracy level of (2%/2 mm) was achieved using AAA with better agreement for 18 MV photon energy.
authors.forename: Tarek
authors.initials: T
authors.lastname: Sahnoun
authors.forename: Leila
authors.initials: L
authors.lastname: Farhat
authors.forename: Anis
authors.initials: A
authors.lastname: Mtibaa
authors.forename: Mounir
authors.initials: M
authors.lastname: Besbes
authors.forename: Jamel
authors.initials: J
authors.lastname: Daoud
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008962:Models, Theoretical; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012986:Software Validation