The injection that may be given prior to Radioactive Iodine (RAI) treatment is recombinant human TSH (brand name Thyrogen). In order for RAI treatment to work effectively, the remaining thyroid tissue must be stimulated to take up as much iodine as possible. One way to do this is by injecting thyrogen to stimulate the thyroid. Radioactive iodine is used to destroy any remaining thyroid cells including cancer cells. Important note: a low iodine diet is recommended for 1 - 2 weeks prior to RAI treatment.