Comparison of different tracers in the follow up of differentiated thyroidcarcinoma

In the follow up of differentiated thyroid carcinoma (DTC) several scintigr aphic methods are used in addition to the serum thyroglobulin and ultrasono graphy of the neck, iodine-131 whole body scintigraphy (WBS), which is perf ormed since many years, is able to detect iodine positive recurrence, lymph node metastases and distant metastases in a very specific way. However, th e problem of I-131 WBS is the fact that only 67% of metastases from DTC acc umulate iodine. Therefore non specific radionuclides like TI-201 or tracers such as Tc-99m Sestamibi or Tc-99m Tetrofosmin and new metabolic tracers l ike F-18 FDG were introduced in the diagnostic work up to detect iodine neg ative metastases as well. This study describes the comparison of different tracers in 35 patients with elevated thyroglobulin and suspicion of metasta tic disease or already known metastases from DTC.