Nuclear Medicine of the Thyroid and Parathyroid Glands

Abstract

The investigation of thyroid disease has changed dramatically during the last 60 years. With the change from clinical assessment alone to sophisticated imaging and in vitro techniques we now can readily diagnose and treat many of the pediatric thyroid diseases. With the introduction of radioactive iodine uptake in the early 1940s through radionuclide scanning in the 1950s and ultrasound in the 1970s, there has been a tremendous improvement in our ability to measure and image thyroid function. The very sensitive in vitro techniques that are now widely available for measuring serum hormone concentrations have improved our specificity and sensitivity in diagnosing thyroid disease especially in the newborn. More specifically, the ability to measure thyroid stimulating hormone (TSH) and thyroid hormones has substantially reduced the need to rely on clinical examination and the venerable radioactive iodine uptake. Now, with the wide availability of high-quality ultrasonography to evaluate the texture and morphology of the thyroid gland, masses not even palpable clinically are detectable; in fact nodules less than 5 mm in size are now often watched by surgeons, rather than investigated.