This study was conducted in patients with differentiated thyroid cancer who had undergone total/near-total thyroidectomy. After surgery patients were randomized to one of two methods of performing thyroid remnant ablation. One group of patients who took thyroid hormone medicine and were euthyroid [i.e. their thyroid stimulating hormone (TSH) levels are normal], and received injections of rhTSH (0.9 mg daily on two consecutive days) followed by oral radioiodine. The second group of patients did not take thyroid hormone medicine so that they were hypothyroid (i.e. their TSH levels were high), and were given oral radioiodine.

Inclusion Criteria:

• Subjects voluntarily sign the informed consent form (ICF).
• Age ≥ 18 years old, either male or female.
• Patients with diagnosed differentiated papillary or follicular thyroid carcinoma, including papillary-follicular variant, characterized as pT 1-3, N 0-1or Nx, and M0.
• Eastern Cooperative Oncology Group (ECOG) score of 0-2;
• Expected life expectancy is greater than 12 weeks;
• Patients with a total or near-total thyroidectomy within 12 months prior to randomized.
• Low iodine diet for two weeks prior to randomized.

Exclusion Criteria:

• patients with recent history of 131I whole body scan within 2 weeks prior to randomized.
• Pregnant or breast feeding women.
• patients with other malignancies (exception for in situ cervix uterine cancer, baso cellular skin cancer or breast cancer in remission)
• Subjects who are unsuitable to the trial in combination with other serious diseases, as identified by the investigator.
• Subjects who have participated in another clinical trial of a new drug or medical instrument within 1 months before screening.