This is a multi-centered, open-labeled, randomized, two parallel-arm study designed to compare quantitative radiation dosimetry assessments obtained during thyroid hormone suppression therapy with recombinant human TSH (Thyrogen® (Registered Trademark)) and hypothyroidism in thyroid cancer patients preparing for post-surgical radioiodine ablation. The primary endpoint of this study is to identify the ratio of administered activity of radioiodine (131I) to deliver a targeted dose of 30,000 rad to the thyroid remnant when patients are euthyroid on Thyrogen® (Registered Trademark) and hypothyroid after hormone withdrawal. Secondary endpoints are to identify and compare effective 131I clearance and cumulated activity in the whole body and blood during euthyroid and hypothyroid states.