title: Dosimetric Analysis of Neural and Vascular Structures in Skull Base Tumors Treated with Stereotactic Radiosurgery.
abstract: Objective To examine the relationship between the prescribed target dose and the dose to healthy neurovascular structures in patients with vestibular schwannomas treated with stereotactic radiosurgery (SRS). Study Design Case series with chart review. Setting SRS center from 2011 to 2013. Subjects Twenty patients with vestibular schwannomas treated at the center from 2011 to 2013. Methods Twenty patients with vestibular schwannomas were included. The average radiation dose delivered to healthy neurovascular structures (eg, carotid artery, basilar artery, facial nerve, trigeminal nerve, and cochlea) was analyzed. Results Twenty patients with vestibular schwannomas who were treated with fused computed tomography/magnetic resonance imaging-guided SRS were included in the study. The prescribed dose ranged from 10.58 to 17.40 Gy over 1 to 3 hypofractions to cover 95% of the target tumor volume. The mean dose to the carotid artery was 5.66 Gy (95% confidence interval [CI], 4.53-6.80 Gy), anterior inferior cerebellar artery was 8.70 Gy (95% CI, 4.54-12.86 Gy), intratemporal facial nerve was 3.76 Gy (95% CI, 3.04-4.08 Gy), trigeminal nerve was 5.21 Gy (95% CI, 3.31-7.11 Gy), and the cochlea was 8.70 Gy (95% CI, 7.81-9.59 Gy). Conclusions SRS for certain vestibular schwannomas can expose the anterior inferior cerebellar artery (AICA) and carotid artery to radiation doses that can potentially initiate atherosclerotic processes. The higher doses to the AICA and carotid artery correlated with increasing tumor volume. The dose delivered to other structures such as the cochlea and intratemporal facial nerve appears to be lower and much less likely to cause immediate complications when shielded.
authors.affiliation: 1 University of California, Irvine Medical Center, Department of Otolaryngology-Head and Neck Surgery, Irvine, California, USA.
authors.forename: Yarah M
authors.initials: YM
authors.lastname: Haidar
authors.affiliation: 1 University of California, Irvine Medical Center, Department of Otolaryngology-Head and Neck Surgery, Irvine, California, USA.
authors.forename: Jay M
authors.initials: JM
authors.lastname: Bhatt
authors.affiliation: 1 University of California, Irvine Medical Center, Department of Otolaryngology-Head and Neck Surgery, Irvine, California, USA.
authors.forename: Yaser
authors.initials: Y
authors.lastname: Ghavami
authors.affiliation: 1 University of California, Irvine Medical Center, Department of Otolaryngology-Head and Neck Surgery, Irvine, California, USA.
authors.forename: Omid
authors.initials: O
authors.lastname: Moshtaghi
authors.affiliation: 2 Newport Diagnostic Cyberknife Center, Newport Beach, California, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Schwer
authors.affiliation: 2 Newport Diagnostic Cyberknife Center, Newport Beach, California, USA.
authors.forename: Stafford
authors.initials: S
authors.lastname: Chenery
authors.affiliation: 1 University of California, Irvine Medical Center, Department of Otolaryngology-Head and Neck Surgery, Irvine, California, USA.
authors.forename: Hamid R
authors.initials: HR
authors.lastname: Djalilian
mesh_terms: D000328:Adult; D000368:Aged; D002140:California; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D009464:Neuroma, Acoustic / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D011379:Prognosis; D011829:Radiation Dosage; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D018570:Risk Assessment; D019291:Skull Base / Q000098:blood supply* / Q000294:innervation* / Q000601:surgery; D019292:Skull Base Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D025321:Surgery, Computer-Assisted; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
keywords: dosimetric analysis; skull base tumors; stereotactic radiosurgery