title: Imaging dose assessment for IGRT in particle beam therapy.
abstract: BACKGROUND
  Image-guided advanced photon and particle beam treatments are promising options for improving lung treatments. Extensive use of imaging increases the overall patient dose. The aim of this study was to determine the imaging dose for different IGRT solutions used in photon and particle beam therapy.
  
  
  METHODS
  Measurements were performed in an Alderson phantom with TLDs. Clinically applied protocols for orthogonal planar kV imaging, stereoscopic imaging, CT scout views, fluoroscopy, CT, 4D-CT and CBCT were investigated at five ion beam centers and one conventional radiotherapy department. The overall imaging dose was determined for a patient undergoing a lung tumor irradiation with institute specific protocols.
  
  
  RESULTS
  OAR doses depended on imaging modality and OAR position. Dose values were in the order of 1 mGy for planar and stereoscopic imaging and 10-50 mGy for volumetric imaging, except for one CBCT device leading to lower doses. The highest dose per exam (up to 150 mGy to the skin) was recorded for a 3-min fluoroscopy.
  
  
  CONCLUSIONS
  Modalities like planar kV or stereoscopic imaging result in very low doses (≈ 1 mGy) to the patient. Imaging a moving target during irradiation, low-dose protocols and protocol optimization can reduce the imaging dose to the patient substantially.
authors.affiliation: Department of Radiation Oncology, Medical University of Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Austria. Electronic address: elisabeth.steiner@akhwien.at.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Steiner
authors.forename: Markus
authors.initials: M
authors.lastname: Stock
authors.forename: Boris
authors.initials: B
authors.lastname: Kostresevic
authors.forename: Alexander
authors.initials: A
authors.lastname: Ableitinger
authors.forename: Urszula
authors.initials: U
authors.lastname: Jelen
authors.forename: Hannah
authors.initials: H
authors.lastname: Prokesch
authors.forename: Alina
authors.initials: A
authors.lastname: Santiago
authors.forename: Petra
authors.initials: P
authors.lastname: Trnková
authors.forename: Adam
authors.initials: A
authors.lastname: Wolf
authors.forename: Andrea
authors.initials: A
authors.lastname: Wittig
authors.forename: Antony
authors.initials: A
authors.lastname: Lomax
authors.forename: Oliver
authors.initials: O
authors.lastname: Jäkel
authors.forename: Guido
authors.initials: G
authors.lastname: Baroni
authors.forename: Dietmar
authors.initials: D
authors.lastname: Georg
mesh_terms: D054893:Cone-Beam Computed Tomography / Q000379:methods; D005260:Female; D063193:Heavy Ion Radiotherapy / Q000379:methods; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D019047:Phantoms, Imaging; D017785:Photons; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D013819:Thermoluminescent Dosimetry / Q000379:methods
keywords: Dosimetry; IGRT; Ion beam therapy; Lung; Particle therapy; SBRT