title: [Gamma knife versus stereotactic linear accelerator. Utilization, clinical results and cost-benefit relations].
abstract: BACKGROUND
  The principles of radiosurgery were developed in 1951 by Leksell. Their technical realization led to the development of the gamma knife and stereotactically modified linear accelerator.
  
  
  METHODS
  In addition to the gamma knife, we present the different principles of convergent beam irradiation (radiosurgery with linear accelerator), the further development to fractionated stereotactic conformal radiotherapy, and the necessary quality-assurance steps.
  
  
  RESULTS
  The greatest uncertainties in the precision of radiosurgery result from medical imaging (CT 0.7 x 0.7 x 1 mm; DSA 1-5 mm; MR angiography < 2 mm). The focusing accuracy of the gamma knife (+/- 0.3 mm) can also be achieved today by linear accelerators using a stereotactic floorstand. For the same indication and the same dosage for the target volume, there are no clinical differences between the gamma knife and the linear accelerator (AVM: 80% complete obliteration; metastases: 85% local tumor control; AN: 90% tumor control). However, there are greater differences in costs. There is no constellation where the gamma knife is just as expensive or more cost-effective than the linear accelerator treatment. The most cost-effective solution is modification of an available linear accelerator, resulting in treatment costs per patient of 9,201.25 DM (50 patients/year).
  
  
  CONCLUSIONS
  There seem to be no methodological, physical, clinical or cost reasons for using a gamma knife, especially because the trend is going towards fractionated conformation radiotherapy instead of the application of high single doses.
authors.affiliation: Abteilung für Strahlentherapie, Radiologische Universitätsklinik, Tübingen.
authors.forename: G
authors.initials: G
authors.lastname: Becker
authors.forename: R
authors.initials: R
authors.lastname: Kortmann
authors.forename: T W
authors.initials: TW
authors.lastname: Kaulich
authors.forename: F
authors.initials: F
authors.lastname: Duffner
authors.forename: M
authors.initials: M
authors.lastname: Bamberg
mesh_terms: D001932:Brain Neoplasms / Q000191:economics / Q000556:secondary / Q000601:surgery*; D003362:Cost-Benefit Analysis; D004867:Equipment Design; D006801:Humans; D011785:Quality Assurance, Health Care; D016634:Radiosurgery / Q000191:economics* / Q000295:instrumentation; D013238:Stereotaxic Techniques / Q000191:economics* / Q000295:instrumentation; D016896:Treatment Outcome
vernacular_title: Gamma-knife versus stereotaktische Linearbeschleunigerbestrahlung. Durchführung, klinische Ergebnisse und Kosten-Nutzen-Relation.