title: Single fraction radiosurgery using Rapid Arc for treatment of intracranial targets.
abstract: BACKGROUND
  Stereotactic-Radio-Surgery (SRS) using Conformal-Arc-Therapy (CAT) is a well established irradiation technique for treatment of intracranial targets. Although small safety margins are required because of very high accuracy of patient positioning and exact online localisation, there are still disadvantages like long treatment time, high number of monitor units (MU) and covering of noncircular targets. This planning study analysed whether Rapid Arc (RA) with stereotactic localisation for single-fraction SRS can solve these problems.
  
  
  METHODS
  Ten consecutive patients were treated with Linac-based SRS. Eight patients had one or more brain metastases. The other patients presented a symptomatic vestibularis schwannoma and an atypic meningioma. For all patients, two plans (CAT/RA) were calculated and analysed.
  
  
  RESULTS
  Conformity was higher for RA with additional larger low-dose areas. Furthermore, RA reduced the number of MU and the treatment time for all patients. Dose to organs at risk were equal or slightly higher using RA in comparison to CAT.
  
  
  CONCLUSIONS
  RA provides a new alternative for single-fraction SRS irradiation combining advantages of short treatment time with lower number of MU and better conformity in addition to accuracy of stereotactic localisation in selected cases with uncomplicated clinical realization.
authors.affiliation: Department of Radiotherapy and Radiooncology, Universitätsmedizin Göttingen, Germany. hendrik.wolff@med.uni-goettingen.de
authors.forename: Hendrik A
authors.initials: HA
authors.lastname: Wolff
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Wagner
authors.forename: Hans
authors.initials: H
authors.lastname: Christiansen
authors.forename: Clemens F
authors.initials: CF
authors.lastname: Hess
authors.forename: Hilke
authors.initials: H
authors.lastname: Vorwerk
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods