Evaluation of Clinical Application and Dosimetric Comparison of Treatment Plans of Gamma Knife and CyberKnife in Treating Arteriovenous Malformations.

Purpose: To analyze and compare the characteristics of dose distributions for Leksell Gamma Knife Perfexion (LGK-PFX) and CyberKnife (CK) in treating arteriovenous malformations (AVMs). Subjects and Methods: Twenty-four patients with AVMs who received CK radiosurgery at a prescribed dose (PD) of 16-25 Gy in a single fraction were selected. A LGK-PFX treatment plan with the same PD was designed for each patient. Dosimetric values for both systems were compared with respect to the conformity index (CI); selectivity index (SI); gradient index (GI) of 75, 50, and 25% of the PD; heterogeneity index; volume of the brain tissue covered by doses of 10 and 12 Gy; maximum dose delivered to the brainstem; and beam-on time. Results: The CIs of LGK-PFX and CK were 0.744 +/- 0.075 and 0.759 +/- 0.071 (p = 0.385), respectively. The SIs of LGK-PFX and CK were 0.764 +/- 0.081 and 0.780 +/- 0.076 (p = 0.424), respectively. The GI(75%), GI(50%), and GI(25%) values of LGK-PFX and CK were 1.028 +/- 0.123 and 2.439 +/- 0.338 (p < 0.001), 3.169 +/- 0.265 and 4.972 +/- 0.852 (p < 0.001), and 8.650 +/- 0.914 and 14.261 +/- 2.476 (p < 0.001), respectively. Volumes of the brain tissue covered by 10 Gy and 12 Gy for LGK-PFX and CK (p < 0.001) exhibited a significant difference. Conclusions: LGK-PFX and CK exhibited similar dose conformity. LGK-PFX showed superior normal tissue sparing. (C) 2017 S. Karger AG, Basel