I'm not a pharm student, but I used to be a nuclear medicine technologist a couple years back. We had a bunch of nuclear pharmacy post-docs but they were all doing research after getting their PhD's (this was in Massachusetts). One of them (the lead one) may have been a PharmD, but maybe not--I have no idea what the regulations are that govern that, because the Pharmacist/PhD wasn't actually dispensing those tracers to patients--the nuclear techs do it. Furthermore, radiopharmaceuticals aren't really "pharmaceuticals" at all--they don't really change the physiology of a normal body enough to be considered a "treatment" for anything.... unless you're talking about bone palliation with heavy radioactive stuff (Strontium, I believe it was), or non-Hodgkins treatments with Bexxar or Zevalin.
p.s. Nuclear Medicine is slowly but surely losing steam. Its clinical applications are getting fewer and fewer, and though there are certain quintessential nuclear exams that will probably always be beneficial (bone scanning for mets, PET scans, stress-tests), different radiologic modalities are making great strides in the treatment of many new/prevalent diseases (angio/fluoroscopy, MRI, fMRI, thin slice CT, etc, etc).
If you love it, do a rotation--really, because you'll learn a lot and it will expose you to the field. But I think--and someone correct me if I'm way off base--the field of nuclear pharm is geared more towards people who are doing *research*--new antibody tracers, new studies in new populations with old tracers, finding new indications for new diseases, using radiopharmaceuticals to trace normal/pathological patterns, and all that).
Good luck to you in school, whatever you choose!