title: Evaluation of dynamic tumour tracking radiotherapy with real-time monitoring for lung tumours using a gimbal mounted linac.
abstract: OBJECTIVE
  To evaluate feasibility and acute toxicities after dynamic tumour tracking (DTT) irradiation with real-time monitoring for lung tumours using a gimbal mounted linac.
  
  
  METHODS
  Spherical gold markers were placed around the tumour using a bronchoscope prior to treatment planning. Prescription dose at the isocentre was 56 Gy in 4 fractions for T2a lung cancer and metastatic tumour, and 48 Gy in 4 fractions for the others. Dose-volume metrics were compared between DTT and conventional static irradiation using in-house developed software.
  
  
  RESULTS
  Of twenty-two patients enrolled, DTT radiotherapy was successfully performed for 16 patients, except 4 patients who coughed out the gold markers, one who showed spontaneous tumour regression, and one where the abdominal wall motion did not correlate with the tumour motion. Dose covering 95% volume of GTV was not different between the two techniques, while normal lung volume receiving 20 Gy or more was reduced by 20%. A mean treatment time per fraction was 36 min using DTT. With a median follow-up period of 13.2 months, no severe toxicity grade 3 or worse was observed.
  
  
  CONCLUSIONS
  DTT radiotherapy using a gimbal mounted linac was clinically feasible for lung treatment without any severe acute toxicity.
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan. Electronic address: ymatsuo@kuhp.kyoto-u.ac.jp.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Matsuo
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Nami
authors.initials: N
authors.lastname: Ueki
authors.affiliation: Division of Radiation Oncology, Institute of Biomedical Research and Innovation, Kobe, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Takayama
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miyabe
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Ishihara
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Mukumoto
authors.affiliation: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Yano
authors.affiliation: Division of Radiation Oncology, Institute of Biomedical Research and Innovation, Kobe, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tanabe
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Mitsubishi Heavy Industries, Ltd., Tokyo, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Kaneko
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Mizowaki
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Monzen
authors.affiliation: Faculty of Medical Science, Kyoto College of Medical Science, Nantan, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sawada
authors.affiliation: Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kokubo
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005240:Feasibility Studies; D005260:Female; D057918:Fiducial Markers; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000601:surgery; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009038:Motion; D016634:Radiosurgery / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Dynamic tumour tracking; Feasibility study; Lung cancer; Real-time monitoring; Stereotactic body radiotherapy