title: Planning study and dose measurements of intracranial stereotactic radiation surgery with a flattening filter-free linac.
abstract: OBJECTIVE
  Flattening filter-free (FFF) beams have recently become available for radiation therapy, offering much higher dose rates but complicating treatment owing to the nonflat profile. Stereotactic treatment is one of the most evident scenarios to investigate the use of FFF beams.
  
  
  METHODS
  We present a planning study of a FFF 7-MV beam for the treatment of brain metastases using multiple noncoplanar arcs. Plan differences as compared with flat 6 MV photon fields are estimated using different measures of quality. Absolute dosimetry and fluence distribution are verified and the out-of-field dose is measured.
  
  
  RESULTS
  The FFF 7-MV plans are slightly better than the flat 6-MV plans as evaluated by a number of quality indices, dose to organs at risk, and out-of-field dose, although differences may not be clinically relevant. Verification does not pose any problems.
  
  
  CONCLUSIONS
  The FFF 7-MV treatment plans are marginally superior to the flat-beam 6-MV plans in almost all cases, with greatly reduced treatment times (almost 50%).
authors.affiliation: Department of Radiation Oncology, Saarland University Medical Center, Homburg, Germany. Electronic address: yvonne.dzierma@uks.eu.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Dzierma
authors.affiliation: Department of Radiation Oncology, Saarland University Medical Center, Homburg, Germany.
authors.forename: Frank G
authors.initials: FG
authors.lastname: Nuesken
authors.affiliation: Department of Radiation Oncology, Saarland University Medical Center, Homburg, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Palm
authors.affiliation: Department of Radiation Oncology, Saarland University Medical Center, Homburg, Germany.
authors.forename: Norbert P
authors.initials: NP
authors.lastname: Licht
authors.affiliation: Department of Radiation Oncology, Saarland University Medical Center, Homburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Ruebe
mesh_terms: D001932:Brain Neoplasms / Q000556:secondary / Q000601:surgery*; D006801:Humans; D010315:Particle Accelerators; D019047:Phantoms, Imaging; D016634:Radiosurgery / Q000295:instrumentation / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods*