For the short term iodine can be very helpful to prevent the uptake of iodine 131. Using iodine for more than two weeks can have problems. Using mixed antioxidants is the best defense against all ionizing radiation. Iodine can induce both hypothyoidism and hyperthyroidism. If you're going to use iodine for more than two weeks it may be helpful to supplement with a grain of thyroid extract a day.