title: Scanned ion beam therapy for prostate carcinoma: Comparison of single plan treatment and daily plan-adapted treatment.
abstract: OBJECTIVE
  Intensity-modulated particle therapy (IMPT) for tumors showing interfraction motion is a topic of current research. The purpose of this work is to compare three treatment strategies for IMPT to determine potential advantages and disadvantages of ion prostate cancer therapy.
  
  
  METHODS
  Simulations for three treatment strategies, conventional one-plan radiotherapy (ConvRT), image-guided radiotherapy (IGRT), and online adaptive radiotherapy (ART) were performed employing a dataset of 10 prostate cancer patients with six CT scans taken at one week intervals. The simulation results, using a geometric margin concept (7-2 mm) as well as patient-specific internal target volume definitions for IMPT were analyzed by target coverage and exposure of critical structures on single fraction dose distributions.
  
  
  RESULTS
  All strategies led to clinically acceptable target coverage in patients exhibiting small prostate motion (mean displacement <4 mm), but IGRT and especially ART led to significant sparing of the rectum. In 20% of the patients, prostate motion exceeded 4 mm causing insufficient target coverage for ConvRT (V95mean = 0.86, range 0.63-0.99) and IGRT (V95mean = 0.91, range 0.68-1.00), while ART maintained acceptable target coverage.
  
  
  CONCLUSIONS
  IMPT of prostate cancer demands consideration of rectal sparing and adaptive treatment replanning for patients exhibiting large prostate motion.
authors.affiliation: Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany.|Department of Radiation Oncology, University Clinic Erlangen and Friedrich- Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hild
authors.affiliation: Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Graeff
authors.affiliation: Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, University Clinic Heidelberg, Heidelberg, Germany.|INFN Sezione di Roma and Dipartimento di Scienze di Base e Applicate per Ingegneria, Sapienza Universit'a di Roma, Roma, Italy.
authors.forename: Antoni
authors.initials: A
authors.lastname: Rucinski
authors.affiliation: Institute for Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany.|Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg, Germany.
authors.forename: Klemens
authors.initials: K
authors.lastname: Zink
authors.affiliation: Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, University Clinic Heidelberg, Heidelberg, Germany.|Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München (TUM), Munich, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Habl
authors.affiliation: Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany.|Faculty of Physics, Technische Universität Darmstadt, Darmstadt, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Durante
authors.affiliation: Heidelberg Ion-Beam Therapy Center (HIT) and Department of Radiation Oncology, University Clinic Heidelberg, Heidelberg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Herfarth
authors.affiliation: Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany. christoph.bert@uk-erlangen.de.|Department of Radiation Oncology, University Clinic Erlangen and Friedrich- Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany. christoph.bert@uk-erlangen.de.|Radiation Oncology, University Hospital Erlangen, Universitätsstraße 27, 91054, Erlangen, Germany. christoph.bert@uk-erlangen.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bert
mesh_terms: D003198:Computer Simulation; D019583:Dose Fractionation, Radiation; D063193:Heavy Ion Radiotherapy / Q000379:methods*; D006801:Humans; D008297:Male; D009038:Motion; D058958:Organs at Risk; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011834:Radiation Monitoring / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D061106:Radiotherapy Setup Errors; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Image-guided radiotherapy; Intensity-modulated radiotherapy; Organs at risk; Prostatic neoplasm; Radiotherapy planning, computer-assisted