radiolabelled thyroxine

Radiolabelled T4 refers to the thyroid hormone thyroxine (T4) that has been chemically tagged with a radioactive isotope, typically iodine-125 or iodine-131. This compound is primarily used as a diagnostic tool in nuclear medicine and laboratory research to study thyroid function, hormone kinetics, and protein binding. In clinical settings, radiolabelled T4 is used in radioimmunoassays for measuring serum levels of free or total T4 and for investigating disorders of thyroid hormone transport or metabolism. The mechanism involves the same biological activity as endogenous thyroxine—regulation of metabolism via activation of nuclear thyroid hormone receptors—but the radioactive label allows tracking and quantification through imaging or detection equipment. Radiolabelled T4 is not used therapeutically but rather as a tracer in diagnostic procedures and research applications[1][7].

Other names

radiolabeled T4radioiodinated thyroxineradioactive T4