title: Initial experience with volumetric IMRT (RapidArc) for intracranial stereotactic radiosurgery.
abstract: OBJECTIVE
  Initial experience with delivering frameless stereotactic radiotherapy (SRT) using volumetric intensity-modulated radiation therapy (IMRT) delivered with RapidArc is presented.
  
  
  METHODS
  Treatment details for 12 patients (14 targets) with a mean clinical target volume (CTV) of 12.8 ± 4.0 cm(3) were examined. Dosimetric indices for conformality, homogeneity, and dose gradient were calculated and compared with published results for other frameless, intracranial SRT techniques, including CyberKnife, TomoTherapy, and static-beam IMRT. Statistics on setup and treatment times and per patient dose validations were examined.
  
  
  RESULTS
  Dose indices compared favorably with other techniques. Mean conformality, gradient, and homogeneity index values were 1.10 ± 0.11, 64.9 ± 14.1, 1.083 ± 0.026, respectively. Median treatment times were 4.8 ± 1.7 min.
  
  
  CONCLUSIONS
  SRT using volumetric IMRT is a viable alternative to other techniques and enables short treatment times. This is anticipated to have a positive impact on radiobiological effect and for facilitating wider use of SRT.
authors.affiliation: Department of Radiation Oncology, University of Massachusetts Medical School, Worcester, MA 01655, USA. charles.mayo@umassmemorial.org
authors.forename: Charles S
authors.initials: CS
authors.lastname: Mayo
authors.forename: Linda
authors.initials: L
authors.lastname: Ding
authors.forename: Anthony
authors.initials: A
authors.lastname: Addesa
authors.forename: Sidney
authors.initials: S
authors.lastname: Kadish
authors.forename: T J
authors.initials: TJ
authors.lastname: Fitzgerald
authors.forename: Richard
authors.initials: R
authors.lastname: Moser
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D005260:Female; D006801:Humans; D007103:Immobilization / Q000379:methods; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D011859:Radiography; D016634:Radiosurgery / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D013997:Time Factors; D047368:Tumor Burden