title: A dosimetric comparison of real-time adaptive and non-adaptive radiotherapy: A multi-institutional study encompassing robotic, gimbaled, multileaf collimator and couch tracking.
abstract: A study of real-time adaptive radiotherapy systems was performed to test the hypothesis that, across delivery systems and institutions, the dosimetric accuracy is improved with adaptive treatments over non-adaptive radiotherapy in the presence of patient-measured tumor motion.
  
  
  
  Ten institutions with robotic(2), gimbaled(2), MLC(4) or couch tracking(2) used common materials including CT and structure sets, motion traces and planning protocols to create a lung and a prostate plan. For each motion trace, the plan was delivered twice to a moving dosimeter; with and without real-time adaptation. Each measurement was compared to a static measurement and the percentage of failed points for γ-tests recorded.
  
  
  
  For all lung traces all measurement sets show improved dose accuracy with a mean 2%/2mm γ-fail rate of 1.6% with adaptation and 15.2% without adaptation (p<0.001). For all prostate the mean 2%/2mm γ-fail rate was 1.4% with adaptation and 17.3% without adaptation (p<0.001). The difference between the four systems was small with an average 2%/2mm γ-fail rate of <3% for all systems with adaptation for lung and prostate.
  
  
  
  The investigated systems all accounted for realistic tumor motion accurately and performed to a similar high standard, with real-time adaptation significantly outperforming non-adaptive delivery methods.
authors.affiliation: Radiation Physics Laboratory, University of Sydney, Australia; Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia.
authors.forename: Emma
authors.initials: E
authors.lastname: Colvill
authors.affiliation: Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia; School of Physics, University of Sydney, Australia.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Booth
authors.affiliation: The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, UK.
authors.forename: Simeon
authors.initials: S
authors.lastname: Nill
authors.affiliation: The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Fast
authors.affiliation: The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, UK.
authors.forename: James
authors.initials: J
authors.lastname: Bedford
authors.affiliation: The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, UK.
authors.forename: Uwe
authors.initials: U
authors.lastname: Oelfke
authors.affiliation: Department of Radiation Oncology and Image-Applied Therapy, Kyoto University, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Aarhus University Hospital, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Poulsen
authors.affiliation: Aarhus University Hospital, Denmark.
authors.forename: Esben
authors.initials: E
authors.lastname: Worm
authors.affiliation: Aarhus University Hospital, Denmark.
authors.forename: Rune
authors.initials: R
authors.lastname: Hansen
authors.affiliation: Aarhus University Hospital, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ravkilde
authors.affiliation: Radiation Medicine Research Center, Rigshospitalet, Copenhagen, Denmark; Niels Bohr Institute, University of Copenhagen, Denmark.
authors.forename: Jonas
authors.initials: J
authors.lastname: Scherman Rydhög
authors.affiliation: Radiation Medicine Research Center, Rigshospitalet, Copenhagen, Denmark; Section of Radiotherapy Physics and Engineering, Medical Physics Department, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Tobias
authors.initials: T
authors.lastname: Pommer
authors.affiliation: Radiation Medicine Research Center, Rigshospitalet, Copenhagen, Denmark; Niels Bohr Institute, University of Copenhagen, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Munck Af Rosenschold
authors.affiliation: Department of Radiation Oncology, University Hospital Zurich, Switzerland.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Lang
authors.affiliation: Department of Radiation Oncology, University Hospital Zurich, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Guckenberger
authors.affiliation: Department of Radiation Oncology, University Hospital of Würzburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Groh
authors.affiliation: Computer Science Department, Würzburg University, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Herrmann
authors.affiliation: Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Verellen
authors.affiliation: Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Belgium.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Poels
authors.affiliation: Radiation Oncology Department, Stanford University, Palo Alto, United States.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Radiation Oncology Department, Stanford University, Palo Alto, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Hadsell
authors.affiliation: Department for Radiation Oncology, University Clinic Eppendorf, Hamburg, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Sothmann
authors.affiliation: Department for Radiation Oncology, University Clinic Schleswig-Holstein, Kiel, Germany; Saphir Radiosurgery Center, Güstrow and Frankfurt am Main, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Blanck
authors.affiliation: Radiation Physics Laboratory, University of Sydney, Australia. Electronic address: paul.keall@sydney.edu.au.
authors.forename: Paul
authors.initials: P
authors.lastname: Keall
mesh_terms: D003199:Computer Systems; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008297:Male; D009068:Movement; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D012371:Robotics / Q000295:instrumentation*
keywords: Couch tracking; Gimbaled tracking; MLC tracking; Organ motion; Robotic tracking