Value of Combined Technetium-99m Hydroxy Methylene Diphosphonate and Thallium-201 Imaging in Detecting Bone Metastases from Thyroid Carcinoma

Detectability of bone metastases from differentiated thyroid carcinoma by technetium-99m hydroxymethylene diphosphonate (99mTc-HMDP) bone scan is considered to be poor. Thallium-201 (201T1) is also widely used for detecting metastatic lesions. Our present study was aimed at the evaluation of the combined use of 99mTc-HMDP and 201T1 imaging in successful detection of bone metastases from differentiated thyroid carcinoma. Twenty-seven thyroidectomized thyroid cancer patients (19 females, 8 males; 12 papillary type, 15 follicular type) with 77 bone lesions were included in this retrospective study. All of these patients received ablative doses of radioiodine. Thyroidal origin of the lesions was proved by positive iodine-131 (131I) uptake. In 131I-negative lesions, histological proof or absence of tumor markers other than thyroglobulin was considered when computed tomography (CT) and/or magnetic resonance imaging (MRI) suggested metastatic nature of the lesions. Of the 77 lesions, 58 (75.3%) were positive and...