21 CFR 315.2 - Definition.
For purposes of this part, diagnostic radiopharmaceutical means:
(a) An article that is intended for use in the diagnosis or monitoring of a disease or a manifestation of a disease in humans and that exhibits spontaneous disintegration of unstable nuclei with the emission of nuclear particles or photons; or
Title 21 published on 2013-04-01
no entries appear in the Federal Register after this date.