One resource I used was US News rankings of not only Neurology/Neurosurgery Dept. but also their more specific category called:
Advanced technologies
Diagnostic radioisotope services, image-guided radiation therapy, PET/CT scanner, single-photon-emission CT and stereotactic radiosurgery.
Example:
University of Texas MD Anderson Cancer Center - an "Excellent" rating of 5 out of 5
...as well as looking at their general rankings in Neurology/Neurosurgery
Example:
Mayo Clinic
(507) 405-0312 | Rochester, MN 55902-1906
#1 in Adult Neurology & Neurosurgery Hospitals
Mayo Clinic in Rochester, MN is nationally ranked in 15 adult specialties and 9 pediatric specialties.
I only considered places ranked in the top 50 and had a perfect score in the category that included:
Advanced technologies of -
Diagnostic radioisotope services, image-guided radiation therapy, PET/CT scanner, single-photon-emission CT and stereotactic radiosurgery.
But that was just me coming up with my own system. Everybody is different.