title: Arc-modulated radiation therapy based on linear  models.
abstract: This paper reports an inverse arc-modulated radiation therapy planning technique based on linear models. It is implemented with a two-step procedure. First, fluence maps for 36 fixed-gantry beams are generated using a linear model-based intensity-modulated radiation therapy (IMRT) optimization algorithm. The 2D fluence maps are decomposed into 1D fluence profiles according to each leaf pair position. Second, a mixed integer linear model is used to construct the leaf motions of an arc delivery that reproduce the 1D fluence profile previously derived from the static gantry IMRT optimization. The multi-leaf collimator (MLC) sequence takes into account the starting and ending leaf positions in between the neighbouring apertures, such that the MLC segments of the entire treatment plan are deliverable in a continuous arc. Since both steps in the algorithm use linear models, implementation is simple and straightforward. Details of the algorithm are presented, and its conceptual correctness is verified with clinical cases representing prostate and head-and-neck treatments.
authors.affiliation: Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA. xiaofeng.zhu@duke.edu
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhu
authors.forename: Danthai
authors.initials: D
authors.lastname: Thongphiew
authors.forename: Ryan
authors.initials: R
authors.lastname: McMahon
authors.forename: Taoran
authors.initials: T
authors.lastname: Li
authors.forename: Vira
authors.initials: V
authors.lastname: Chankong
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Yin
authors.forename: Q Jackie
authors.initials: QJ
authors.lastname: Wu
mesh_terms: D000465:Algorithms; D005240:Feasibility Studies; D006257:Head / Q000528:radiation effects; D006258:Head and Neck Neoplasms / Q000532:radiotherapy; D006801:Humans; D016014:Linear Models; D008297:Male; D009333:Neck / Q000528:radiation effects; D011467:Prostate / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D011829:Radiation Dosage; D011878:Radiotherapy / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D012669:Seminal Vesicles / Q000528:radiation effects