<unk> s are substances used to enhance the visibility of internal structures in X-ray-based imaging techniques such as computed tomography (contrast CT), projectional radiography, and fluoroscopy.<unk> s are typically iodine, or more rarely barium sulfate. The contrast<unk> s absorb external X-rays, resulting in decreased exposure on the X-ray detector. This is different from radiopharmaceuticals used in nuclear medicine which emit radiation. Magnetic resonance imaging (MRI) functions through different principles and thus MRI contrast<unk> s have a different mode of action. These compounds work by altering the magnetic properties of nearby hydrogen nuclei.
Radiocontrast agent
Contrast agent
Blood pool agent
Radioactive tracer
Iodinated contrast
Steroid
Immunoconjugate
Antibiotic