It is not a pleasant procedure. Don't let these folks fool you into thinking it is easy. But it's a lot easier than surgery. They give you Valium, the put 4 screws into your head and attach a frame (metal, heavy). You don't feel it at at that point because you get local anesthesia but you will feel it when the screws come out and the anesthesia has worn off. You go into the machine. It's like an MRI but silent, completely silent, no noise, no smell, no lights. You are there for 45 minutes usually. After wards they take the frame out, bandage your head and you go home.
From that point on everyone reacts differently. So I can't tell you how you will feel. I did not feel well after the procedure and a year later still don't feel well.
I had severe problems after the GK, which continue and my tumor has grown. Bad headaches, which still continue, eye swelled up and bled (I think they screwed the screws too tight in one side of my head). A feeling of pressure in the head which still continues; eye spasms, memory problems, concentration problems which all continue etc. My tongue tingles and my taste buds have changed. But you may not have any symptoms other than it will hurt where they put in the screws for a while. Take some pain killers and you may be fine. I am still struggling and I was told that 18 months out is when the worst side effects occur. I am not there yet. But my tumor has grown by 5 mm after the radiation, a lot more than they said it would. I am now in the large category. This growth seems different than what others have experienced from the radiation.
Good luck. You will be fine. I seem to be more of an exception.
dee-dee