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Glossary

Showing 651-660 out of 1156 Terms

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  • Intrathecal

    (IN-truh-THEE-kul)

    Describes the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord. Drugs can be injected into the fluid or a sample of the fluid can be removed for testing.

  • Intrathecal Chemotherapy

    (IN-truh-THEE-kul KEE-moh-THAYR-uh-pee)

    Treatment in which anticancer drugs are injected into the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord.

  • Intravenous

    (IN-truh-THEE-kul)

    The administration of a drug or fluid directly into the vein.

  • Intravenous pyelogram

    (IN-truh-VEE-nus PY-eh-loh-GRAM)

    An x-ray image of the kidneys, ureters, and bladder. It is made after a substance that shows up on x-rays is injected into a blood vessel. The substance outlines the kidneys, ureters, and bladder as it flows through the system and collects in the urine. An intravenous pyelogram is usually made to look for a block in the flow of urine.

  • Invasive cancer

    (in-VAY-siv KAN-ser)

    Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called infiltrating cancer.

  • Investigational drugs

    A substance that has been tested in the laboratory and has been approved by the U.S. Food and Drug Administration (FDA) for testing in people. Clinical trials test how well investigational drugs work and whether they are safe to use. An investigational drug may be approved by the FDA for use in one disease or condition but still be considered investigational in other diseases or conditions. Also called experimental drug, IND, investigational agent, and investigational new drug.

  • Ionizing Radiation

    (I-uh-NY-zing RAY-dee-AY-shun)

    A type of high-energy radiation that has enough energy to remove an electron (negative particle) from an atom or molecule, causing it to become ionized. Ionizing radiation can cause chemical changes in cells and damage DNA. This may increase the risk of developing certain health conditions, such as cancer. Ionizing radiation can come from natural sources, such as radon and cosmic rays (rays that enter the earth's atmosphere from outer space). It may also come from medical imaging equipment, such as x-ray, CT scan, or PET scan machines. Nuclear power plant accidents and atomic weapons also release high levels of ionizing radiation. Being exposed to very high doses of ionizing radiation can cause immediate damage to a person’s body, including severe skin or tissue damage, acute radiation sickness, and death.

  • Irradiated

    (ih-RAY-dee-AY-ted)

    Treated with radiation.

  • Irradiation

    (ih-RAY-dee-AY-shun)

    The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy or brachytherapy). Systemic irradiation uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called radiation therapy and radiotherapy.

  • Irreversible toxicity

    (eer-ree-VER-sih-bul tok-SIH-sih-tee)

    Side effects that are caused by toxic substances or something harmful to the body and do not go away.