title: Radiation sparing of cerebral cortex in brain tumor patients using quantitative neuroimaging.
abstract: OBJECTIVE
  Neurocognitive decline in brain tumor patients treated with radiotherapy (RT) may be linked to cortical atrophy. We developed models to determine radiation treatment-planning objectives for cortex, which were tested on a sample population to identify the dosimetric cost of cortical sparing.
  
  
  METHODS
  The relationship between the probability of cortical atrophy in fifteen high-grade glioma patients at 1-year post-RT and radiation dose was fit using logistic mixed effects modeling. Cortical sparing was implemented using two strategies: region-specific sparing using model parameters, and non-specific sparing of all normal brain tissue.
  
  
  RESULTS
  A dose threshold of 28.6 Gy was found to result in a 20% probability of severe atrophy. Average cortical sparing at 30 Gy was greater for region-specific dose avoidance (4.6%) compared to non-specific (3.6%). Cortical sparing resulted in an increase in heterogeneity index of the planning target volume (PTV) with an average increase of 1.9% (region-specific) and 0.9% (non-specific).
  
  
  CONCLUSIONS
  We found RT doses above 28.6 Gy resulted in a greater than 20% probability of cortical atrophy. Cortical sparing can be achieved using region-specific or non-specific dose avoidance strategies at the cost of an increase in the dose heterogeneity of the PTV.
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Roshan A
authors.initials: RA
authors.lastname: Karunamuni
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Moore
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Tyler M
authors.initials: TM
authors.lastname: Seibert
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Radiology, University of California San Diego, La Jolla, United States.
authors.forename: Nathan S
authors.initials: NS
authors.lastname: White
authors.affiliation: Department of Radiology, University of California San Diego, La Jolla, United States.
authors.forename: Hauke
authors.initials: H
authors.lastname: Bartsch
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Ruben
authors.initials: R
authors.lastname: Carmona
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Deborah
authors.initials: D
authors.lastname: Marshall
authors.affiliation: Department of Psychiatry, University of California San Diego, La Jolla, United States.
authors.forename: Carrie R
authors.initials: CR
authors.lastname: McDonald
authors.affiliation: Department of Radiology, University of California San Diego, La Jolla, United States.
authors.forename: Nikdokht
authors.initials: N
authors.lastname: Farid
authors.affiliation: Department of Radiology, University of California San Diego, La Jolla, United States.
authors.forename: Anithapriya
authors.initials: A
authors.lastname: Krishnan
authors.affiliation: Department of Radiology, University of California San Diego, La Jolla, United States.
authors.forename: Joshua
authors.initials: J
authors.lastname: Kuperman
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Loren K
authors.initials: LK
authors.lastname: Mell
authors.affiliation: Department of Radiology, University of California San Diego, La Jolla, United States.
authors.forename: James
authors.initials: J
authors.lastname: Brewer
authors.affiliation: Department of Radiology, University of California San Diego, La Jolla, United States.
authors.forename: Anders M
authors.initials: AM
authors.lastname: Dale
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States.
authors.forename: Vitali
authors.initials: V
authors.lastname: Moiseenko
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, United States. Electronic address: jhattangadi@ucsd.edu.
authors.forename: Jona A
authors.initials: JA
authors.lastname: Hattangadi-Gluth
mesh_terms: D000328:Adult; D001284:Atrophy / Q000517:prevention & control; D001932:Brain Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D002540:Cerebral Cortex / Q000473:pathology / Q000528:radiation effects*; D015331:Cohort Studies; D005240:Feasibility Studies; D005260:Female; D005910:Glioma / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D059906:Neuroimaging / Q000379:methods*; D011832:Radiation Injuries / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*
keywords: Cortex; Glioma; OAR; Radiation sparing