24. Neck CT#3, axial plane

The plane of imaging is through the T1 vertebra. Note how the two lobes of the thyroid gland stand out because they are denser than any of the surrounding muscles; this is due to the high concentration of iodine in the thyroid gland. Iodine is a component of thyroid hormone, and its high atomic number makes the thyroid denser than muscle and most other glandular tissue.