. . "0"^^ . . . . . . . . . "(radiology) any radioactive isotope introduced into the body to study metabolism or other biological processes"@en-us . . . "0"^^ . . . "04462835-n"^^ . . . . . "tracer"@en-us . "104290021"@en-us . . . . "104462835"^^ . "tracer"^^ .