Final answer:
Thyroid nodules do not spread via blood although cancerous thyroid nodules can metastasize. The thyroid gland, which produces hormones like thyroxine, can be imaged and treated with radioactive iodine isotopes.
Step-by-step explanation:
Thyroid nodules themselves do not typically spread through the blood. Instead, they are localized growths within the thyroid gland, which is located at the front of the neck and plays a crucial role in regulating metabolism. However, if a thyroid nodule is cancerous, it is possible for the cancer to spread or metastasize to other parts of the body through the bloodstream or the lymphatic system. Thyroid cancer metastasis varies depending on the type of cancer and its aggressiveness. Treatment and diagnosis may involve the use of radioactive iodine due to the gland's unique ability to absorb iodine for the production of thyroid hormones.
Within the thyroid gland, there are two types of cells that produce hormones: follicular cells, which synthesize thyroxine (T4) and triiodothyronine(T3), and parafollicular cells, which produce calcitonin. Medical imaging with radioactive isotopes such as I-131 and I-123 is often used in the diagnosis and treatment of thyroid conditions because they are taken up by the thyroid gland.