title: Computational modeling of beam-customization devices for heavy-charged-particle radiotherapy.
abstract: A model for beam customization with collimators and a range-compensating filter based on the phase-space theory for beam transport is presented for dose distribution calculation in the treatment planning of radiotherapy with protons and heavier ions. Independent handling of pencil beams in conventional pencil-beam algorithms causes unphysical collimator-height dependence in the middle of large fields, which is resolved by the framework comprised of generation, transport, collimation, regeneration, range-compensation and edge-sharpening processes with a matrix of pencil beams. The model was verified to be consistent with measurement and analytic estimation at a submillimeter level in the penumbra of individual collimators with a combinational-collimated carbon-ion beam. The model computation is fast, accurate and readily applicable to pencil-beam algorithms in treatment planning with the capability of combinational collimation to make the best use of the beam-customization devices.
authors.affiliation: Department of Accelerator and Medical Physics, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan. nkanemat@nirs.go.jp
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kanematsu
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Yonai
authors.forename: Azusa
authors.initials: A
authors.lastname: Ishizaki
authors.forename: Masami
authors.initials: M
authors.lastname: Torikoshi
mesh_terms: D002244:Carbon / Q000737:chemistry; D003198:Computer Simulation; D004583:Electrons; D011878:Radiotherapy / Q000295:instrumentation* / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012680:Sensitivity and Specificity
chemical_list: D002244:Carbon