Positron emission tomography (PET) is a highly sensitive, low invasive technology for cancer biology imaging. The role of F-18 FDG PET/CT in differentiated thyroid cancer (DTC) is well established, particularly in patients presenting with elevated Tg levels and negative radioactive iodine WBS. It has been demonstrated that F-18 FDG uptake represents less differentiated thyroid cancer cells or dedifferentiated cells and PET positive lesions are more likely to be resistant to 131I treatment. The uptake of F-18 FDG is related to tumor size, thyroid capsule invasion and histological variants with a poor prognosis. As in other cancers, early detection of recurrences improves outcomes and survival. 124I PET/CT can also be used to image the patients with DTC, similarly to 123I WBS. Compared with F-18 FDG PET/CT, its spatial resolution is only slightly degraded but increasing the imaging time reduces this difference. In addition, F-18 FDG PET/CT has been found helpful in the management of patients with anaplastic and medullary thyroid cancer. Other radiopharmaceuticals such as 68Ga-DOTATOC and F-18 DOPA may provide complimentary information to F-18 FDG PET/CT in the detection of recurrent thyroid cancer.
From the Division of Nuclear Medicine, Stanford University Medical Center, Stanford, CA.
Received for publication February 19, 2011; revision accepted April 1, 2011.
Conflicts of interest and sources of funding: none declared.
Reprints: Andrei Iagaru, MD, Division of Nuclear Medicine, Stanford University Medical Center, 300 Pasteur Dr, H-2200, Stanford, CA 94305–5281. E-mail: email@example.com.