title: First clinical application of a prompt gamma based in vivo proton range verification system.
abstract: OBJECTIVE
  To improve precision of particle therapy, in vivo range verification is highly desirable. Methods based on prompt gamma rays emitted during treatment seem promising but have not yet been applied clinically. Here we report on the worldwide first clinical application of prompt gamma imaging (PGI) based range verification.
  
  
  METHODS
  A prototype of a knife-edge shaped slit camera was used to measure the prompt gamma ray depth distribution during a proton treatment of a head and neck tumor for seven consecutive fractions. Inter-fractional variations of the prompt gamma profile were evaluated. For three fractions, in-room control CTs were acquired and evaluated for dose relevant changes.
  
  
  RESULTS
  The measurement of PGI profiles during proton treatment was successful. Based on the PGI information, inter-fractional global range variations were in the range of ±2 mm for all evaluated fractions. This is in agreement with the control CT evaluation showing negligible range variations of about 1.5mm.
  
  
  CONCLUSIONS
  For the first time, range verification based on prompt gamma imaging was applied for a clinical proton treatment. With the translation from basic physics experiments into clinical operation, the potential to improve the precision of particle therapy with this technique has increased considerably.
authors.affiliation: OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany; German Cancer Consortium (DKTK), Dresden, Germany. Electronic address: christian.richter@oncoray.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Richter
authors.affiliation: OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; Helmholtz-Zentrum Dresden - Rossendorf, Germany.
authors.forename: Guntram
authors.initials: G
authors.lastname: Pausch
authors.affiliation: OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Barczyk
authors.affiliation: Helmholtz-Zentrum Dresden - Rossendorf, Germany.
authors.forename: Marlen
authors.initials: M
authors.lastname: Priegnitz
authors.affiliation: OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany.
authors.forename: Isabell
authors.initials: I
authors.lastname: Keitz
authors.affiliation: Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Thiele
authors.affiliation: Ion Beam Applications SA, Louvain-la-Neuve, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: Smeets
authors.affiliation: Ion Beam Applications SA, Louvain-la-Neuve, Belgium.
authors.forename: Francois Vander
authors.initials: FV
authors.lastname: Stappen
authors.affiliation: XGLab S.R.L., Milano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Bombelli
authors.affiliation: Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Fiorini
authors.affiliation: Ion Beam Applications SA, Louvain-la-Neuve, Belgium.
authors.forename: Lucian
authors.initials: L
authors.lastname: Hotoiu
authors.affiliation: Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Perali
authors.affiliation: Ion Beam Applications SA, Louvain-la-Neuve, Belgium.
authors.forename: Damien
authors.initials: D
authors.lastname: Prieels
authors.affiliation: OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany; German Cancer Consortium (DKTK), Dresden, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Enghardt
authors.affiliation: OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; Department of Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; Helmholtz-Zentrum Dresden - Rossendorf, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany; German Cancer Consortium (DKTK), Dresden, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Baumann
mesh_terms: D003528:Carcinoma, Adenoid Cystic / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D005720:Gamma Rays / Q000627:therapeutic use*; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D061766:Proton Therapy / Q000379:methods*; D014057:Tomography, X-Ray Computed
keywords: First in man; Prompt gamma imaging; Proton therapy; Range verification; Slit camera