I'm doing FSR in Atlanta in a couple of weeks. The way I went about it was that I did a lot of research on the web and on this site to see which radiation methods can be fractionated. Then I searched for hospitals in the area which had these radiation methods, and I'm working with a radiation oncologist at a local hospital here. The Trilogy System is what I'll be using at Piedmont in Atlanta and the radiation oncologist was trained on it at Emory (a teaching hospital here) by the expert here in Atlanta.
Most neurosurgeons are trained to do surgery and gamma knife or cyberknife. Usually they do not do FSR, which is why they don't typically recommend it. I didn't get the information and support I wanted until I talked to a well-trained radiation oncologist about it. FSR has not been used as long as GK and CK, but there is research on it and it does look promising, even though there are obviously cases of failure and poor side effects which you'll see on this site.
FSR is fractionated stereotactic radiotherapy. If you go to pubmed.gov and search for it in regards to AN, you will find the latest research on it. Also I've seen others here mention the Univ. of Pittsburgh site which apparently also has a lot of information on ANs. You can also google the Trilogy System (Craig has it's website address on one of his posts) to find out more about it. There probably is one in PA, and the site will locate it for you.
If you do your research and read posts on this site, as well as consult with different kinds of doctors, you'll be able to make the right choice for you. I wish you luck in your journey, and if you'd like to know more about my FSR treatments, I'll be starting on June 18 and I'll be posting my experience while I'm doing it.