ABSTRACT
To investigate diagnostic value of Thallium 201(T1-201) thymid scan in differentiating malignant nodule from benign, 135 patients with thyroid nodule were evaluated with Tl-201 thyroid scan, fine needle aspiration(FNA), clinical characteristics and laboratory data. Each had histological diagnosis after thyroidectomy. Tl-201 scan had a sensitivity of 67.3% and a specificity of 66.3% and FNA had sermitivity of 46.9% and specificity of 100% in predicting malignancy. As the size of thyroid nodule and age of patient incteases, diagnostic value of 11-201 thyroid scan was improved. In the thyroid nodules larger then 3cm, sensitivity, specificity and negative predictive value were 100%, 70% and 100%, reqectively. By cornbining Tl-201 throid scan and FNA, sensitivity had 91.8%. From the data we conclude that Tl-201 thyroid scan is valuable with adjuvant diagnostic method in differentiating malignant fmm benign thyroid nodule and treatment planning.