Condition of Patient with Well-differentiated Thyroid Cancer for ¹³¹I Scintigraphy or Therapy

To assess whether the patient preparation procedure for  ¹³¹ I scintigraphy could be streamlined, the time course of TSH elevation were analysed after total thyroidectomy and after ablation thyroid remnants and the first follow up withdrawal thyroxine(T4) in patient with thyroid cancer. The clinical records of 142 patients with differentiated thyroid cancer were studied. All patients had undergoes total thyroidectomy. Two group patients were evaluated. The immediate postoperative group consisted 83 patients who were not given thyroid hormone replacement after surgery because of planned postoperative ^{ 131} I ablation thyroid remnants. The other group consisted of 59 patients in whom T4 replacement was stopped in preparation for whole body  ¹³¹ I scintgraphy. The first TSH measurement and number of days were recorded after surgery or stopped thyroid hormone for each patient. In immediate postoperative group, TSH levels obtained 14 30 d (median 16 d) after surgery ranged from 15.8 to 145 mIU/L (median, 45.4 mIU/L). The TSH values exceed 30 mIU/L in 83% of patients evaluated at 2 weeks, in 86% of those evaluated at 3 weeks, and in 88% of those valuated after 3 weeks. In withdrawal T4 group, TSH levels obtained from 13 35 d (median 22 d), later ranged from 21 92 mIU/L (median, 60.1 mIU/L). The TSH values exceeded 30 mIU/L in 87% of patients evaluated at 2 weeks, in 90% of those evaluated at 3 weeks and in 97% of those valuated after 3 weeks. In most patients with thyroid cancer being prepared for  ¹³¹ I imaging or therapy, a TSH level exceeding 30 mIU/L can be attained by withdrawal of thyroid hormone therapy 2 3 weeks, the duration of thyroxine withdrawal can be decreased to 3 weeks.