Re: Radioactive Iodine Pill
The pill is given most often for overactivity of the gland - like you had. It most often kills off all of the gland, which cures the hyperT by trading it for hypoT. Even though doctors tell patients it will kill only part, it nearly always renders a person hypothyroid afterward.
RAI is also given as part of the treatment for thyroid cancer. The gland is first removed surgically, but because thyroid tissue can regenerate from the remaining bits of tissue surrounding the parathyroids that have to be left in place, administering RAI will kill off those remaining bits in order to prevent regrowth and possible recurrence of cancer.
It appears that you did NOT have cancer, because your gland was not removed and your nodules went away or reduced.