X-ray photon attenuation by iodine via photoelectric absorption

This entry does not refer to a biological target such as a receptor, enzyme, or transporter. Instead, it describes a *physical process*: the strong attenuation (absorption) of X-ray photons by iodine, a high atomic number element, via the photoelectric effect. This property is exploited in diagnostic radiology, particularly as iodinated contrast media for imaging modalities such as CT, angiography, and fluoroscopy. When X-ray photon energy is near iodine's k-edge (33.2 keV), photoelectric absorption is maximized, resulting in increased local image contrast. This is a physical-chemical effect, not a biological mechanism. No direct biological pathway, signaling, or molecular interaction underlies this "target".

Other names

Iodine photoelectric absorptionIodine X-ray attenuationIodine-based X-ray contrast enhancement

Physical attenuation of X-ray photons by high atomic number element (iodine) via the photoelectric effect at diagnostic energies