University of Nebraska Medical Center


Radiation therapy may involve terms that are new to you. The following terminology may be used during treatment.

  • Adjuvant treatment: A treatment that is given in addition to the primary treatment to enhance its effectiveness and reduce the chance of the tumor recurring.
  • Applicator: A device used to hold a radioactive source in place during brachytherapy.
  • Beam films: Another term for port films, beam films are pictures of the position of the radiation beams used to treat cancer. They are used to verify the position of the beams and confirm that treatment is delivered to the right place.
  • Blocks: Pieces of metal alloy that can be used to shape the radiation beam.
  • Boost: An additional dose of radiation that is given after an initial course of radiation to enhance tumor control. A boost may be given to the tumor and areas to which the tumor may have spread.
  • Brachytherapy: Internal radiation therapy which involves placing radioactive sources inside or adjacent to the tumor.
  • Clinical trials: Studies that test new cancer therapies.
  • High-dose-rate (HDR) remote afterloading machine: A medical device that allows radiation to be delivered into a patient's body through catheters during brachytherapy.
  • Hyperfractionated radiation therapy: A type of radiation therapy in which the radiation doses are divided into smaller amounts (hyperfractionation) and patients undergo radiation treatment more than once a day.
  • Hypofractionated radiation therapy: A type of radiation therapy in which patients undergo one or just a few treatments.
  • Immobilization device: A device that is used to help a patient remain in the same position during every treatment.
  • Intensity modulated radiation therapy or IMRT: IMRT is a specialized form of external beam therapy that allows radiation to be shaped to fit your tumor.
  • Interstitial brachytherapy: A form of seed implant where the radioactive sources are placed directly into the tumor, such as the prostate.
  • Intracavity brachytherapy: A type of brachytherapy where the radioactive seeds are put into a space where the tumor is located, such as the cervix or windpipe.
  • Linear accelerator: The most common type of machine used to deliver external radiation therapy. Sometimes called a "linac."
  • Multileaf collimator or MLC: A part of a linear accelerator that is used to shape the radiation beam.
  • Palliative care/palliation: Treatment that is intended to relieve symptoms, but not cure a disease.
  • PET scan: A positron emission tomography scan uses a small dose of a chemical called a radionuclide combined with a sugar, which is injected into the patient. The radionuclide emits positrons. The PET scanner detects the positron emissions given off by the radionuclide.
  • Proton beam therapy: An external beam therapy that uses protons rather than X-rays to treat tumors.
  • Radioimmunotherapy: The use of radiolabeled antibodies to deliver radiation directly to a tumor.
  • Radiolabeled antibodies: Monoclonal antibodies (antibodies produced in a laboratory) that have had a radioactive isotope attached to them in a process called radiolabeling.
  • Radioprotector: A type of drug that protects normal tissues in the area being treated.
  • Radioresistant: A term used to describe a tumor that does not respond well to radiation therapy.
  • Radiosensitize: A type of drug that can make a tumor respond better to radiation therapy.
  • Simulation: The process of planning radiation therapy to allow the radiation to be delivered to the intended location.
  • Treatment plan: A radiation oncologist's prescription which describes how a patient should be treated with radiation therapy. The radiation oncology team uses sophisticated treatment planning software to maximize radiation to the tumor while sparing healthy tissue.