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.
Medical Definition of RADIOISOTOPE. : a radioactive isotopeâcompare radioelement. â raÂ·dioÂ·isoÂ·toÂ·pic \-ËÄ«-sÉ-Ëtaep-ËtÃ¤p, -ik-ËtÅp\ ik. â adjectiveÂ·raÂ·dioÂ·isoÂ·toÂ·piÂ·cal \-ly-i(k-)É\ lÄ. adverbedical Definition of RADIOISOTOPE. : a radioactive isotopeâcompare radioelement. â raÂ·dioÂ·isoÂ·toÂ·pic \-ËÄ«-sÉ-Ëtaep-ËtÃ¤p, -ik-ËtÅp\ ik. â adjectiveÂ·raÂ·dioÂ·isoÂ·toÂ·piÂ·cal \-ly-i(k-)É\ lÄ. adverb