Reacquisition of Radioactive Iodine (RAI) Uptake of RAI-Refractory Metastatic Thyroid Cancers by Pretreatment With the Selective MEK Inhibitor AZD6244

"Within 1 week of starting the study: Low iodine diet~The patient will receive three bottles of capsules containing the drug AZD6244. Each capsule contains 25 milligrams of AZD6244. They will take 3 capsules orally, by mouth twice a day for 4 weeks. AZD6244 should be taken on an empty stomach (either one hour before or 2 hours after meals). AZD6244 capsules should be taken with water only. Lesional dosimetry with iodine-124 PET will be done twice, at the beginning and at the end of the study. This is done the same way that a radioactive iodine scan is done and is spread out over 5 days. It requires injection with human recombinant TSH (Thyrogen) on day 1 and 2, as well as blood tests on day 1 and day 5. On day 3, you will receive the iodine-124 in form of an oral drink, and the PET scan will be obtained on day 5. You will need to follow a low iodine diet starting 5 days before and throughout the process."