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.

Hearing Function after CyberKnife for Vestibular Schwannoma: A Systematic Review

“…After 99 duplicates were removed, 123 articles were submitted an analysis of the title and abstract, and 77 were excluded. The 46 remaining articles had their full text read, and 33 were excluded due to the following reasons: the hearing classification system specified in the eligibility criteria was not used or it was used inadequately (for example: considering GR grade III or AAO-HNS class C as serviceable hearing); [15][16][17][18][19] inadequate study design; [20][21][22][23] incomplete study; [24][25][26][27][28][29][30][31][32][33][34] use of another radiation source; 35,36 same population from others studies; [37][38][39][40][41] and inadequate data report [42][43][44][45][46][47] (the corresponding authors of these studies were contacted to request additional information, but there was no response). Then, a total of 13 studies [48][49][50][51][52][53][54][55][56][57][58]…”