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.
It is nuclear. reactor produced. The quantities of radioisotopes used per analysis are of course much. lower than per in vivo study of a patient, and hence so are the total quantities. involved. Therefore, and not because they are not important, we will not further deal. with these in vitro aspects in this report.