title: Philosophy of the tracer method.
mesh_terms: D002140:California; D049673:History, 20th Century; D007553:Isotope Labeling / Q000379:methods; D009683:Nuclear Medicine / Q000266:history; D011849:Radioactive Tracers; D011868:Radioisotopes
chemical_list: D011849:Radioactive Tracers; D011868:Radioisotopes