“Radiopharmaceutical” means any substance defined as a drug in 21 U.S.C. § 321(g)(1) which:
1. Exhibits spontaneous disintegration of unstable nuclei which emit nuclear particles or photons; or
2. Is intended to be made radioactive.
Ê The term includes nonradioactive reagent kits and nuclide generators which are used in the preparation of any substance. The term does not include drugs containing compounds of carbon or potassium or salts containing potassium which contain trace quantities of naturally occurring radionuclides.