In scintigraphy, which tracer is primarily used for thyroid imaging?

In scintigraphy for thyroid imaging, Iodine-123 is primarily used because it closely mimics the behavior of naturally occurring iodine in the body, particularly in the thyroid gland. This isotope is selectively taken up by the thyroid tissue, allowing for detailed visualization of thyroid function and anatomy.

Iodine-123 has a suitable half-life of about 13 hours, which makes it ideal for diagnostic imaging without exposing the patient to excessive radiation. Additionally, it emits gamma rays that can be easily detected by a gamma camera, providing clear images of the thyroid gland.

The other tracers mentioned are not suitable for thyroid imaging. Fluorine-18 is commonly used in PET scans for different types of imaging, particularly for cancer detection and metabolic activity assessment. Gallium-67 is primarily utilized in imaging certain types of infections and tumors. Technetium-99m is a widely used tracer in nuclear medicine, but it is more often associated with procedures such as bone scans and cardiac imaging rather than specifically for evaluating thyroid function.