CT exams over a lifetime and Iodine necessity?

In the last 12 years I have undergone 4 CT scans.  2 Brain and 2 Pelvic.  The two pelvic scans were with contrast, the first one I had to drink a large amount of Berrium, and the second was with Iodine. One brain and one pelvic have been done within two months of each other.  I am quite concerned with the number of CT scans that I have had, and honestly speaking all of them have been unnecessary.  I would like to know what my risk is for any radiation damage or increased risk of cancers because of all of these scans?  In addition my last CT was just a week ago and I would like to know if I should take Iodine tablets now for awhile to avoid thyroid uptake of the radition?  How long should I take them at what dosage and how many per day for how long?

Thanks!

[demtlard]

As a year has almost approached, I am bumping this topic back up to try to get a reply