It sounds like Stereo-tactic surgery. I have had it post craniotomy, but I guess they could use it for a tumor like your brothers. It is a method they use to deliver a one time high dose of radiation and it is very accurate. Keep in mind this is a guess here, but it sounds like that is what they're doing. I have read about it being used in conjunction with standard surgery and I imagine they would need a special operating room. I had mine 6 weeks post-op and it was done in a standard radiation room. Keep in mind, it may be a good sign that his hospital offers this procedure.