Radiation Terms

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  • Brachytherapy

    means radiation that is being emitted in close proximity to or inside the cancer tumor. It is also referred to as "implant therapy".

  • Half-life

    the time in which one half of the atoms of a particular radioactive substance disintegrates into another nuclear form. Half-lives vary from millionths of a second to billions of years.

  • Implant therapy

    small radioactive seeds are implanted in or near the cancer lesions. Seeds may be implanted permanently or temporarily depending on the type of cancer being treated.

  • mrem

    unit of radiation dose. It is the product of the absorbed dose (i.e., the amount of energy imparted in the body) and a quality factor for the type of ionizing radiation being measured.

  • Radiation

    particles or photons emitted from the nucleus of unstable radioactive atoms as a result of radioactive decay Also, it refers to x-rays emitted by an x-ray machine.

  • Radioactive contamination

    deposition of radioactive material in any place where it could potentially be harmful to individuals.

  • Radioactive decay

    decrease in the amount of any radioactive material with the passage of time due to the spontaneous emission of radiation from an atomic nucleus.

  • Radioisotope

    an unstable isotope of an element that decays or disintegrates spontaneously, emitting radiation.

  • Radiopharmaceutical therapy (capsule or liquid therapy)

    Patients who have had their thyroid removed because of cancer typically undergo this treatment. Radioactive I-131 capsules or liquid is administered to a patient orally. The I-131 enters the bloodstream and is "taken up" by any remaining thyroid cancer cells. The radiation from the I-131 will destroy these remaining cancer cells. Another type of treatment is radiolabeled antibody therapy. Patients undergoing treatment for lymphoma or leukemia are administered I-131 labeled antibodies intravenously, and will remain in radiation isolation for a much longer period of time than the thyroid cancer patients Remaining I-131 is eliminated via the urine, feces and other bodily fluids.

  • Seeds

    small metal sources containing radioactive material. Seeds are made of radioactive material which is sealed and doubly encapsulated in metal.

SEE ALSO Radiation Safety Manual Glossary


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