title: Integration of functional neuroimaging in CyberKnife radiosurgery: feasibility and dosimetric results.
abstract: OBJECTIVE
  The integration of state-of-the-art neuroimaging into treatment planning may increase the therapeutic potential of stereotactic radiosurgery. Functional neuroimaging, including functional MRI, navigated brain stimulation, and diffusion tensor imaging-based tractography, may guide the orientation of radiation beams to decrease the dose to critical cortical and subcortical areas. The authors describe their method of integrating functional neuroimaging technology into radiosurgical treatment planning using the CyberKnife radiosurgery system.
  
  
  METHODS
  The records of all patients who had undergone radiosurgery for brain lesions at the CyberKnife Center of the University of Messina, Italy, between July 2010 and July 2012 were analyzed. Among patients with brain lesions in critical areas, treatment planning with the integration of functional neuroimaging was performed in 25 patients. Morphological and functional imaging data sets were coregistered using the Multiplan dedicated treatment planning system. Treatment planning was initially based on morphological data; radiation dose distribution was then corrected in relation to the functionally relevant cortical and subcortical areas. The change in radiation dose distribution was then calculated.
  
  
  RESULTS
  The data sets could be easily and reliably integrated into the Cyberknife treatment planning. Using an inverse planning algorithm, the authors achieved an average 17% reduction in the radiation dose to functional areas. Further gain in terms of dose sparing compromised other important treatment parameters, including target coverage, conformality index, and number of monitor units. No neurological deficit due to radiation was recorded at the short-term follow-up.
  
  
  CONCLUSIONS
  Radiosurgery treatments rely on the quality of neuroimaging. The integration of functional data allows a reduction in radiation doses to functional organs at risk, including critical cortical areas, subcortical tracts, and vascular structures. The relative simplicity of integrating functional neuroimaging into radiosurgery warrants further research to implement, standardize, and identify the limits of this procedure.
authors.affiliation: Departments of Neurosurgery, CyberKnife Center, University of Messina, Messina 98125, Italy. alfredo.conti@unime.it
authors.forename: Alfredo
authors.initials: A
authors.lastname: Conti
authors.forename: Antonio
authors.initials: A
authors.lastname: Pontoriero
authors.forename: Giuseppe K
authors.initials: GK
authors.lastname: Ricciardi
authors.forename: Francesca
authors.initials: F
authors.lastname: Granata
authors.forename: Sergio
authors.initials: S
authors.lastname: Vinci
authors.forename: Filippo F
authors.initials: FF
authors.lastname: Angileri
authors.forename: Stefano
authors.initials: S
authors.lastname: Pergolizzi
authors.forename: Concetta
authors.initials: C
authors.lastname: Alafaci
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Rizzo
authors.forename: Angelo
authors.initials: A
authors.lastname: Quartarone
authors.forename: Antonino
authors.initials: A
authors.lastname: Germanò
authors.forename: Roberto Israel
authors.initials: RI
authors.lastname: Foroni
authors.forename: Costantino
authors.initials: C
authors.lastname: De Renzis
authors.forename: Francesco
authors.initials: F
authors.lastname: Tomasello
mesh_terms: D001921:Brain / Q000473:pathology / Q000601:surgery*; D056324:Diffusion Tensor Imaging / Q000379:methods / Q000592:standards; D005240:Feasibility Studies; D059907:Functional Neuroimaging / Q000379:methods* / Q000592:standards; D006801:Humans; D011829:Radiation Dosage; D016634:Radiosurgery / Q000379:methods* / Q000592:standards; D012189:Retrospective Studies