X-ray contrast agents — the contrast agents used in radiodiagnosis. Are applied to improvement of visualization of internals and anatomical structures at beam methods of a research (a x-ray computer tomography and a X-ray analysis).
X-ray contrast means subdivide into two groups. Carry the drugs absorbing x-ray emission to the first group is weaker than body tissues (X-ray negative X-ray contrast means), the second group is made by the substances absorbing x-ray emission in much bigger degree than biological fabrics (X-ray positive X-ray contrast means).
The X-ray positive drugs used in most cases, as a rule, contain iodine or barium. As X-ray negative contrast agents air, nitrous oxide, carbon dioxide are applied.
Most often use X-ray positive means. They have to meet following requirements: to absorb x-ray emission much stronger, than body tissues, i.e. to be high-contrast; to have hypotoxicity as are entered into bodies in high doses; to be brought quickly out of an organism; to have high solubility in water (75-80% solutions are applied to some types of researches); on osmotic effect to be close to blood. Best of all RKS on the basis of derivatives of triiodbenzoyny acid meet these requirements.