Prostate Cancer brachytherapy may expose the thyroid gland to radiation?

It seems a long way from the prostate to the thyroid gland, but the tiny seeds implanted in the prostate, which contain radioactive iodine, may break open and release I/131 iodine into the blood stream. The thyroid is the main site for uptake of the iodine. Cleveland Clinic doctors describe a case where there was increased uptake of the radioiodine in the patients thyroid gland.The doctors looked for seed migration in 246 cases. 23,184 seeds were implanted. 75 seeds were released into the urine, while 25 migrated to the chest.The case with the thyroid radiation probably had the seeds damaged inside the prostate, releasing I/131 into the blood stream, where it would head to the thyroid for uptake. The use of this type of therapy is on the increase. If the radiation dose to the thyroid is above normal, they can block the radioiodine uptake with iodine solution, or KI. Any radiation to the thyroid is significant, and therefore this may be another source of radiation induced thyroid disease.The thyroid doctor may need to ask about the type of prostate cancer therapy in his history taking from now on. Read the whole article at Journal of Urology Nov 2004.