Iodine [131I] sodium oral solution is mainly used for the diagnosis and treatment of thyroid diseases and the preparation of iodine [131I] labeled compounds.

　　Iodine [131I] nuclide is a beta decay nuclide, emitting beta rays (99%) and gamma rays (1%). The maximum energy of beta rays is 0.6065 MeV, the main gamma ray energy is 0.364 MeV; the half-life is 8.02 day. Due to the thyroid's ability to concentrate iodine, it occupies an important position in the treatment of thyroid diseases.