title: Initial clinical experience with frameless stereotactic radiosurgery: analysis of accuracy and feasibility.
abstract: OBJECTIVE
  To report on preliminary clinical experience with a novel image-guided frameless stereotactic radiosurgery system.
  
  
  METHODS
  Fifteen patients ranging in age from 14 to 81 received radiosurgery using a commercially available frameless stereotactic radiosurgery system. Pathologic diagnoses included metastases (12), recurrent primary intracranial sarcoma (1), recurrent central nervous system (CNS) lymphoma (1), and medulloblastoma with supratentorial seeding (1). Treatment accuracy was assessed from image localization of the stereotactic reference array and reproducibility of biteplate reseating. We chose 0.3 mm vector translation error and 0.3 degree rotation about each axis as the maximum tolerated misalignment before treating each arc.
  
  
  RESULTS
  The biteplates were found on average to reseat with a reproducibility of 0.24 mm. The mean registration error from CT localization was found to be 0.5 mm, which predicts that the average error at isocenter was 0.82 mm. No patient treatment was delivered beyond the maximum tolerated misalignment. The radiosurgery treatment was delivered in approximately 25 min per patient.
  
  
  CONCLUSIONS
  Our initial clinical experience with stereotactic radiotherapy using the infrared camera guidance system was promising, demonstrating clinical feasibility and accuracy comparable to many frame-based systems.
authors.affiliation: Department of Neurosurgery, University of Iowa College of Medicine, Iowa City, IA, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Ryken
authors.forename: S L
authors.initials: SL
authors.lastname: Meeks
authors.forename: E C
authors.initials: EC
authors.lastname: Pennington
authors.forename: P
authors.initials: P
authors.lastname: Hitchon
authors.forename: V
authors.initials: V
authors.lastname: Traynelis
authors.forename: N A
authors.initials: NA
authors.lastname: Mayr
authors.forename: F J
authors.initials: FJ
authors.lastname: Bova
authors.forename: W A
authors.initials: WA
authors.lastname: Friedman
authors.forename: J M
authors.initials: JM
authors.lastname: Buatti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000556:secondary / Q000601:surgery*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009066:Mouth, Edentulous; D016634:Radiosurgery / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D012107:Research Design