title: [Physical characterizations for an integrated 160-leaf multi-leaf collimator with a new concept design].
abstract: In this article, we present a physical characterization of the agility(™) (Elekta). agility(™) is composed of 160 interdigitating multileaf collimators (MLCs) with a width of 5 mm at the isocenter. The physical characterizations that include leaf position accuracy, leakage, field penumbra and the tongue-and-groove (T&G) effect were evaluated using well-commissioned 4, 6 and 10-MV photon beams. The leaf position accuracy was within 0.5 mm for all gantry angles and each MLC. The leakage was 0.44% on average and reached 0.47% at 10 MV: remarkably low due to a new design with tilted leaves. However, the T&G effect occurred due to tilt. It was approximately 20.8% on average and reached 22.3% at 6 MV. The penumbra width increased up to 8.5 mm at a field size of 20×20 cm at 4 MV. High position designed MLCs create a wider penumbra but show lower leakage and large head clearance. Head clearance is an important factor in stereotactic radiotherapy with multiple non-coplanar beams.
authors.affiliation: Department of Radiological Technology, Kumamoto University Hospital.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakaguchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Oono
authors.forename: Fujio
authors.initials: F
authors.lastname: Araki
authors.forename: Masato
authors.initials: M
authors.lastname: Maruyama
mesh_terms: D004867:Equipment Design; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000295:instrumentation*