Sorry for the late reply but here it is. I live near NY and had my first surgery at NYU in 1988. When I had a recurrence, I visited Gamma centers in NY as well as surgeons (sometimes it is one and the same). I am aware of only two Gamma centers in NY - NYU and Columbia Presbyterian. I spoke to both just to find out what is Gamma is all about and whether or not I have to go through the open head surgery.
First of all, they both bad-mouth each other, the fact that I did not like. It kind of takes away from both of their competence. Secondly, NYU does not share their success rate with everybody else but Columbia does. That does not mean, of course, that you won't be a sucess at NYU. Plenty of people here on the board are and don't complain. Columbia was more thorough and told me about my tumor and already weakened facial nerve from the previous surgery. In additon, I found out that Columbia ( I am not sure about NYU, you would have to ask) uses a manual control system of positioning whereas between each shot of Gamma technicians will manually position me. The tumors that are not perfectly spherical get "hot" and "cold" spots from Gamma radiation. I don't know what your tumor is like but mine was far from it. I also don't know how many shots - isocenters- you would need. I needed a lot, way more than ten! Finally, Columbia program is older, they did more ANs and is very renowned for that. So. keep this in mind also.
The golden standard in US is Pittsburg location of Gamma. It is the oldest installation in the US and they wrote extensively on the subject in professional literature. They use automatic positioning system and newer system version which results in less radiation to the body as well as greater precision. They offer free consultations and have long term data. If you are interested, send me a PMl and I will find an e-mail that arranges a free consultation with Gamma center in Pittsburgh.
Good luck to you, I hope everything works out!