I never had it either, but Tomo, a form of IMRT, different program, uses CT guidance in real time, which is good for moveable tumors, and works slice by slice, around the patient. There was a study with IMRT vs Tomo posted here a while ago, I think I may have, and believe Tomo was better in certain aspects, outcome.
Tomo seemed popular in 2009 when I was going to have radiation, and now I hardly read about it, everything is IMRT/IGRT, but some center who have it, still use it. Maybe other future investments seem worthwhile...Proton therapy.
http://en.m.wikipedia.org/wiki/TomotherapyHere it is. It's more of a challenge from the makers of Tomo.
http://medicalphysicsweb.org/cws/article/research/33598