Sharif M et al. Serum hyaluronic acid level as a predictor of disease progression in osteoarthritis of the knee. Arthritis Rheum 38:760-767, 1995; Hochberg MC et al. Serum levels of insulin-like growth factor 1 in subjects with osteoarthritis of the knee. Arthritis Rheum 37:1177-1180, 1994
Stable isotopes of an element do not change over time. Atoms of unstable isotopes â also called radioisotopes--change into other elements over time through radioactive decay. Radioisotopes are used in many medical imaging and diagnostic procedures, with the isotope Tc-99m being used in 80 percent of tests.
Autoradiography not only permits the definition of the radioisotopeâs localization in a biological object but also helps to find the quantity of the radioisotope, since the number of reduced silver grains in the emulsion is proportional to the number of particles reacting with the emulsion.