The study will accept patients with non-medullary thyroid cancer who are preparing for ablation therapy. The patients will be placed in one of two groups. Group one will receive Thyrogen in 2 doses 24 hours apart. Group two will receive Thyrogen in 3 doses 72 hours apart. The patients will undergo two 131I whole body scans: one after Thyrogen while taking thyroid hormone suppressive and the second after withdrawal from thyroid hormone. 131I ablative therapy will be given under hypothyroid conditions at the completion of the study.