Sodium Iodide is a crystalline salt commonly used in the Finkelstein reaction via an SN2 pathway, detection of radiation, and in the conversion of an alkyl chloride into an alkyl iodide. When activated with thallium, Sodium Iodide can be subjected to ionizing radiation, emitting photons, which makes it essential in detecting gamma rays using scintillation detectors. Biologically, Sodium Iodide is used in PCR, the Sodium Iodide symporter, and to produce chemokines, particularly CCL2, CXCL8, and CXC14 by stimulation of thyroid follicular cells.