title: Review of clinical brachytherapy uncertainties: analysis guidelines of GEC-ESTRO and the AAPM.
abstract: OBJECTIVE
  A substantial reduction of uncertainties in clinical brachytherapy should result in improved outcome in terms of increased local control and reduced side effects. Types of uncertainties have to be identified, grouped, and quantified.
  
  
  METHODS
  A detailed literature review was performed to identify uncertainty components and their relative importance to the combined overall uncertainty.
  
  
  RESULTS
  Very few components (e.g., source strength and afterloader timer) are independent of clinical disease site and location of administered dose. While the influence of medium on dose calculation can be substantial for low energy sources or non-deeply seated implants, the influence of medium is of minor importance for high-energy sources in the pelvic region. The level of uncertainties due to target, organ, applicator, and/or source movement in relation to the geometry assumed for treatment planning is highly dependent on fractionation and the level of image guided adaptive treatment. Most studies to date report the results in a manner that allows no direct reproduction and further comparison with other studies. Often, no distinction is made between variations, uncertainties, and errors or mistakes. The literature review facilitated the drafting of recommendations for uniform uncertainty reporting in clinical BT, which are also provided. The recommended comprehensive uncertainty investigations are key to obtain a general impression of uncertainties, and may help to identify elements of the brachytherapy treatment process that need improvement in terms of diminishing their dosimetric uncertainties. It is recommended to present data on the analyzed parameters (distance shifts, volume changes, source or applicator position, etc.), and also their influence on absorbed dose for clinically-relevant dose parameters (e.g., target parameters such as D90 or OAR doses). Publications on brachytherapy should include a statement of total dose uncertainty for the entire treatment course, taking into account the fractionation schedule and level of image guidance for adaptation.
  
  
  CONCLUSIONS
  This report on brachytherapy clinical uncertainties represents a working project developed by the Brachytherapy Physics Quality Assurances System (BRAPHYQS) subcommittee to the Physics Committee within GEC-ESTRO. Further, this report has been reviewed and approved by the American Association of Physicists in Medicine.
authors.affiliation: Department of Radiotherapy, Comprehensive Cancer Center, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Austria. Electronic address: christian.kirisits@meduniwien.ac.at.
authors.forename: Christian
authors.initials: C
authors.lastname: Kirisits
authors.affiliation: Department of Radiation Oncology, Tufts University School of Medicine, Boston, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Rivard
authors.affiliation: Department of Medical Physics & Engineering, Sana Klinikum Offenbach, Germany.
authors.forename: Dimos
authors.initials: D
authors.lastname: Baltas
authors.affiliation: University of Valencia, Spain.
authors.forename: Facundo
authors.initials: F
authors.lastname: Ballester
authors.affiliation: University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Marisol
authors.initials: M
authors.lastname: De Brabandere
authors.affiliation: Quality Radiation Therapy, The Netherlands.
authors.forename: Rob
authors.initials: R
authors.lastname: van der Laarse
authors.affiliation: Nucletron an Elekta Company, The Netherlands.
authors.forename: Yury
authors.initials: Y
authors.lastname: Niatsetski
authors.affiliation: Medical Physics Laboratory, Medical School, University of Athens, Greece.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Papagiannis
authors.affiliation: Department of Medical Physics, Oslo University Hospital, The Radium Hospital, Oslo, Norway; Department of Physics, University of Oslo, Oslo, Norway.
authors.forename: Taran Paulsen
authors.initials: TP
authors.lastname: Hellebust
authors.affiliation: Hospital Universitario La Fe, Valencia, Spain.
authors.forename: Jose
authors.initials: J
authors.lastname: Perez-Calatayud
authors.affiliation: Aarhus University Hospital, Denmark.
authors.forename: Kari
authors.initials: K
authors.lastname: Tanderup
authors.affiliation: Department of Medical Physics and Engineering, Instituut Verbeeten, Tilburg, The Netherlands.
authors.forename: Jack L M
authors.initials: JL
authors.lastname: Venselaar
authors.affiliation: University Hospital S-H Campus Kiel, Germany.
authors.forename: Frank-André
authors.initials: FA
authors.lastname: Siebert
mesh_terms: D001918:Brachytherapy / Q000379:methods* / Q000592:standards*; D019583:Dose Fractionation, Radiation; D006801:Humans; D009369:Neoplasms / Q000532:radiotherapy*; D017410:Practice Guidelines as Topic; D035501:Uncertainty
keywords: Brachytherapy; Dosimetry; Treatment planning; Uncertainties