Radioactive tracer

A radioactive tracer, also called a radioactive label, is a substance containing a radioisotope. Tracers can be used to measure the speed of chemical processes and to track the movement of a substance through a natural system. Radioactive tracing was developed by George de Hevesy.

The tracers are applied in autoradiography, nuclear medicine, including single photon emission computed tomography (SPECT), and positron emission tomography.