title: Efficiency and dose planning comparisons between the Perfexion and 4C Leksell Gamma Knife units.
abstract: OBJECTIVE
  We analyzed the efficiency of the Leksell Gamma Knife Perfexion (LGK PFX) in the treatment of multiple metastases and benign tumors. We also compared treatment planning conformity between LGK PFX and LGK 4C for benign tumors.
  
  
  METHODS
  Over a 6-week interval, 37 patients (21 with multiple brain metastases and 16 with benign tumors) underwent radiosurgery using LGK PFX at the University of Pittsburgh. We created dose plans for all patients using Leksell Gamma Plan for LGK PFX and LGK 4C. The same doses were prescribed for both LGK PFX and LGK 4C.
  
  
  RESULTS
  No significant difference was observed between LGK 4C and LGK PFX for total beam-on time. The median reduction in setup time on the LGK PFX was 53 min per patient (range 19-125 min) for multiple metastases. The median reduction in setup time on the LGK PFX for benign tumors was 16 min per patient (range 5-53 min). There was no significant difference in the dose conformality between LGK 4C and LGK PFX.
  
  
  CONCLUSIONS
  This study demonstrated that in addition to its enhanced cranial reach, LGK PFX provided a significant improvement in efficiency for patients with multiple brain metastases. For benign tumor radiosurgery LGK PFX provided improvement in efficiency without a significant difference in conformality.
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh, and Center for Image-Guided Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA. niranjana@upmc.edu
authors.forename: Ajay
authors.initials: A
authors.lastname: Niranjan
authors.forename: Josef
authors.initials: J
authors.lastname: Novotny
authors.forename: Jagdish
authors.initials: J
authors.lastname: Bhatnagar
authors.forename: John C
authors.initials: JC
authors.lastname: Flickinger
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
mesh_terms: D001932:Brain Neoplasms / Q000473:pathology / Q000556:secondary / Q000601:surgery; D006801:Humans; D011829:Radiation Dosage; D016634:Radiosurgery / Q000379:methods* / Q000592:standards*