c) Contrast medium

e) x-ray imaging with contrast media; barium and iodine


contrast media → used to improve the visibility of structures with a low attenuation coefficient


for the photoelectric effect

  • attenuation coefficient atomic number³


soft tissues → average atomic number of 7

barium → atomic number of 53

iodine → atomic number of 56

  • barium/iodine → more absorbant than soft tissues


barium sulfate → used in the digestive system

iodine → used in liquids (blood)