Table 2.

The α, β, and α/β parameter estimates for the fitted survival curves when 9L cells were treated with 0-16 Gy using the LGK U, LGK 4C, and LGK PFX. Survival (S) was measured 4 times for each unit and fitted to the equation log(S) = αD – βD² for each experiment where D is the dose in Gy. The values given for α, β, and α/β represent the mean ± SEM average over the 4 experiments for each LGK unit. There were no significant differences among the units for α, β, or the α/β ratio.

Leksell Gamma Knife Unit	α	β	α/β
U	0.033 ± 0.004	0.0082 ± 0.0007	4.16 ± 0.86
4C	0.052 ± 0.002	0.0076 ± 0.0009	7.10 ± 0.98
Perfexion	0.032 ± 0.009	0.0083 ± 0.0007	3.90 ± 1.07