99m Tc-MIBI scintigraphy versus 131I whole body scan in the follow-up of patients with differentiated thyroid carcinoma

Abstract

Thyroid cancer is the most common endocrine malignancy. More than 90% of primary thyroid cancers are papillary or follicular types, together termed Differentiated Thyroid Cancers (DTC. The aim of this study was to assess to what extent 99mTc-MIBI Whole Body Scan (WBS) improves detectability of negative 1311 scan in follow-up of patients with DTC. This descriptive and prospective study was performed over 40 patients with DTC who were referred to Dr. Dabiri Nuclear Medicine Center from 2004-2005. Six months after total thyroidectomy and 1311 ablation therapy, all patients underwent 131199mTc-MIBI WBS. Serum thyroglobulin was measured by radioimmunoassay method. Serum TSH levels was >30 ?U mL-1 in all patients. 99mTc-MIBI showed 93.75% sensitivity and 87.5% specificity. The figures for 1311 scan were 87.5 and 100%, respectively. It is concluded that considering the slightly higher sensitivity of 99mTc-MIBI, this radio tracer can be used for follow-up of patients with negative 1311 study and patients on suppression therapy.