Radioactive isotopes have many useful applications in medicine and research. In medicine, cobalt-60 is used as a radiation source to treat cancer. Radioactive isotopes are also used as tracers in diagnostic tests and to study metabolic processes. Tracer techniques involve using radioactive or stable isotopes as markers incorporated into precursor compounds to study biosynthetic pathways in plants. Different isotopes are used depending on the application, and their detection methods include mass spectroscopy and NMR spectroscopy.