Thyroid Imaging

Nuclear medicine techniques, like iodine uptake measurements, planar scintigraphy, and positron emission tomography (PET), are very helpful in the management of a number of thyroid disorders. The thyroid gland can trap radioactive iodine as well as the widely used 99mTc isotope. Non-iodine radioactive isotopes are also useful, primarily in the context of PET. The emission of γ‎ -photons enables detection by a gamma camera, resulting in the generation of a two- or three-dimensional thyroid image. In contrast to most other imaging methods, nuclear medicine techniques reflect the functional status of the thyroid tissue. Among other advantages, this feature aids in the management of patients with thyroid nodular diseases in order to diagnose thyroid malignancy. In patients with established thyroid cancer, various techniques, like radioiodine whole-body scan or PET, are very sensitive for detection and localizing of residual malignant thyroid tissue. This chapter focuses on and discusses advantages and limitations of nuclear medicine techniques in thyroid diseases.