title: Quality assurance of a gimbaled head swing verification using feature point tracking.
abstract: To perform dynamic tumor tracking (DTT) for clinical applications safely and accurately, gimbaled head swing verification is important. We propose a quantitative gimbaled head swing verification method for daily quality assurance (QA), which uses feature point tracking and a web camera. The web camera was placed on a couch at the same position for every gimbaled head swing verification, and could move based on a determined input function (sinusoidal patterns; amplitude: ± 20 mm; cycle: 3 s) in the pan and tilt directions at isocenter plane. Two continuous images were then analyzed for each feature point using the pyramidal Lucas-Kanade (LK) method, which is an optical flow estimation algorithm. We used a tapped hole as a feature point of the gimbaled head. The period and amplitude were analyzed to acquire a quantitative gimbaled head swing value for daily QA. The mean ± SD of the period were 3.00 ± 0.03 (range: 3.00-3.07) s and 3.00 ± 0.02 (range: 3.00-3.07) s in the pan and tilt directions, respectively. The mean ± SD of the relative displacement were 19.7 ± 0.08 (range: 19.6-19.8) mm and 18.9 ± 0.2 (range: 18.4-19.5) mm in the pan and tilt directions, respectively. The gimbaled head swing was reliable for DTT. We propose a quantitative gimbaled head swing verification method for daily QA using the feature point tracking method and a web camera. Our method can quantitatively assess the gimbaled head swing for daily QA from baseline values, measured at the time of acceptance and commissioning.
authors.affiliation: Hiroshima High-Precision Radiotherapy Cancer Center, 3-2-2, Futabanosato, Higashi-ku Hiroshima, 732-0057, Japan.
authors.forename: Hideharu
authors.initials: H
authors.lastname: Miura
authors.affiliation: Hiroshima High-Precision Radiotherapy Cancer Center, 3-2-2, Futabanosato, Higashi-ku Hiroshima, 732-0057, Japan.|Department of Radiation Oncology, Institute of Biomedical and Health Science, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Ozawa
authors.affiliation: Hiroshima High-Precision Radiotherapy Cancer Center, 3-2-2, Futabanosato, Higashi-ku Hiroshima, 732-0057, Japan.
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Enosaki
authors.affiliation: Hiroshima High-Precision Radiotherapy Cancer Center, 3-2-2, Futabanosato, Higashi-ku Hiroshima, 732-0057, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawakubo
authors.affiliation: Hiroshima High-Precision Radiotherapy Cancer Center, 3-2-2, Futabanosato, Higashi-ku Hiroshima, 732-0057, Japan.
authors.forename: Fumika
authors.initials: F
authors.lastname: Hosono
authors.affiliation: Hiroshima High-Precision Radiotherapy Cancer Center, 3-2-2, Futabanosato, Higashi-ku Hiroshima, 732-0057, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Hiroshima High-Precision Radiotherapy Cancer Center, 3-2-2, Futabanosato, Higashi-ku Hiroshima, 732-0057, Japan.|Department of Radiation Oncology, Institute of Biomedical and Health Science, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nagata
mesh_terms: D004867:Equipment Design; D057918:Fiducial Markers; D006257:Head / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D007259:Infrared Rays; D009068:Movement; D009369:Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D010363:Pattern Recognition, Automated; D019047:Phantoms, Imaging; D011785:Quality Assurance, Health Care / Q000592:standards*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*
keywords: Vero4DRT; computer processing; dynamic tumor tracking; quality assurance