tracer atom

Both S and P contain at least one isotopic expression of a tracer atom.

Environmental scientists use radioactive atoms, known as tracer atoms, to identify the pathways taken by pollutants through the environment.

The substitution location has to be specifically defined depending on the number of tracer atoms , number of substitutions , and molecule structure.

Technically, however, many radiopharmaceuticals incorporate a radioactive tracer atom into a larger pharmaceutically-active molecule, which is localized in the body, after which the radionuclide tracer atom allows it to be easily detected with a gamma camera or similar gamma imaging device.