They are basically radioactive chemicals/elements that can be injected (harmlessly) into your body for CT scans that could reveal damaged/clogged capillaries in the human body. (That's just one use)
THEY ARE USED TO TRACE THE MOVEMENT OF THE ATOMS, MOLECULES In the Various Metabolic pathways. Also used to trace out secendory metabolites and Intermediate products of cycle like krebs cycle,CALVIN CYcle. ALSO USED IN D.N.A FINGERPRINTING.
