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 2014-04-01.
No entries appear in the Federal Register after this date, for 21 CFR Part 315.