Technetium

Technetium occurring as TcO₄⁻ is specifically taken up by cells expressing the human sodium/iodide symporter (hNIS), a transmembrane glycoprotein that normally mediates iodide uptake into thyroid follicular cells. This restricts the optake to the thyroid, gastric mucosa, salivary, and lacrimal glands, making it a potential radionuclide for therapy in oncology [6].