X-ray attenuation via photoelectric absorption by iodine

X-ray attenuation via photoelectric absorption by iodine refers to the process in which iodine atoms, due to their high atomic number (Z = 53), absorb x-ray photons primarily through the photoelectric effect. This property is exploited in medical imaging, particularly with iodinated contrast agents used in computed tomography (CT) and other x-ray-based modalities. The high atomic number of iodine (Z = 53) causes a significant increase in photoelectric absorption of x-rays, particularly at energies near its k-edge (33.2 keV). This enhanced absorption provides a mechanism to enhance image contrast in tissues where iodine is present. Iodinated compounds are used as exogenous CT contrast agents because they significantly increase local x-ray attenuation. Factors affecting x-ray absorption include x-ray energy, iodine concentration, and molecular structure. Clinical applications include vascular imaging, tumor detection, organ delineation, and perfusion studies. Limitations include reduced efficacy at higher tube voltages and potential adverse effects such as hypersensitivity reactions and nephrotoxicity.

Other names

Iodine contrast enhancementIodine x-ray absorptionIodine k-edge absorption

Photoelectric absorption of x-ray photons by iodine atoms, particularly near the k-edge (33.2 keV), leading to increased x-ray attenuation and image contrast.