March 16, 2009 -- Question: How long will I be "radioactive" after seed implant therapy?
Answer: The permanent radioactive seeds have a half-life dependent upon what type of seeds are used. Half-life means the time it takes for the radioactive source to decay by half the amount. Typically three half-lives -- the decay would then be at 12 percent. So, for an iodine seed implant, three half-lives would be approximately six months. After six months, the radioactivity would be very small.