Could Gamma Knife Surgery Affect Memory And Intellectually?

Last year December my son age 24 yearshad undergone the Retrosigmoid of the Acoustic Schwannoma. This year end of June took MRI and the impression of the report is that residual /recurrent left vestibular schwannoma with predominant intracanicular and small extracanicular (cisternal) components.

No mass effect on brain stem.

But the surgeons suggested to for the option of gamma knife.

I would like to know would gamma knife cause any harm to him such as memory and intellectual since he is of young age still going to college.

Please advice