Radiation Oncology

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Additional Patient Information

What is Radiation Therapy?

Radiation therapy is the use of ionizing radiation in the treatment of malignant tumors or cancers.  Radiation can be administered in several different ways, the most common being through high energy x-rays.

A tumor is a growth or swelling on the surface of or inside the body.  Tumors may be benign or malignant.  Most benign tumors need only simple treatment which may include radiation therapy.

Malignant tumors can grow out of control and may spread within the body.  They must be treated promptly to prevent further growth.  Radiation therapy kills the cells of the tumor by preventing the from reproducing.  The growth of the tumor can be slowed and in many cases completely stopped.  Depending on the type of cancer, radiation therapy may be used alone or in combination with surgery, or drugs (chemotherapy).

Meet the Radiation Therapy Team

You are first referred to a radiation oncologist.  The radiation oncologist is a medical doctor with many years of specialized training in the treatment of cancer and related medical diseases by radiation therapy.  He or she examines you and studies your medical history.  The need for treatment and the treatment schedule is discussed with you and your referring physician.

Under care in the department, you will meet a number of highly trained professionals.  The radiation oncologist is the the leader of a team of individuals that will help you with your treatment.  He or she will make the decisions about whether radiation therapy is needed, the areas to be treated, the doses to be given and the equipment to be used.

You are examined at least once a week by the radiation oncologist who supervises your treatment and who makes any changes necessary to match the changes in the tumor and your general condition.  Your radiation oncologist manages any side effects and notes any physical changes, keeps in contact with your referring doctor and if necessary, recommends other forms of treatment to achieve the best result.  When your treatment is complete, you will be examined periodically to keep track of your progress.

Resident physicians help your doctor and take an active part in your treatment.  They are licensed physicians who are training in the advanced specialty of radiation oncology.  They interview and examine you weekly and are excellent sources of information if you have questions.

Radiation therapists, under the direction of your doctor, give you the radiation treatments. They schedule your daily appointments, position you on the table, adjust the devices used in your treatment, operate the machine, take the appropriate films, and keep records of your treatment course.

Physician assistants, advanced nurse practitioners, and registered nurses all work with the doctor in coordinating and monitoring your care and treatment and are able to assist you with any medical problems that may arise. They are always available to you and your family and are also a good source of information.

Radiation (or medical) physicists are scientists who specialize in the delivery and measurement of radiation. Dosimetrists specialize in radiation dosage. Both are important components of the team.


Radiation therapy involves using many terms you may have never heard before. Below is a list of words you may hear during your 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 that involves placing radioactive sources inside or adjacent to the tumor.
  • Cancer
    A group of diseases in which abnormal cells divide uncontrollably, forming a tumor or mass.
  • Catheter
    A tube inserted into the body that can be used to deliver radiation during brachytherapy.
  • Clinical trials
    Studies that test new cancer therapies.
  • CT or CAT scan
    A computer assisted tomography scan is an X-ray procedure that uses a computer to produce detailed pictures of the body.
  • High-dose-rate 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.
  • Implants
    Another term for brachytherapy, internal radiation therapy involves placing radioactive sources inside the patient close to or in the tumor.
  • 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."
  • Metastases
    Cancer that has spread from one part of the body to another, such as from the breast to the lymph nodes or bones.
  • Monoclonal antibody
    A type of antibody that is created in the laboratory.
  • MR or MRI scan
    A magnetic resonance imaging scan is a procedure that uses a magnetic field to create detailed pictures of the body.
  • Multileaf collimator or MLC
    A part of a linear accelerator that is used to shape the radiation beam.
  • Neutron beam therapy
    A specialized type of external beam radiation therapy similar to proton therapy.
  • Palliative care/palliation
    Treatment that is intended to relieve symptoms, but not cure 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.
  • Radiation oncologist
    A doctor who specializes in treating cancer and other diseases with radiation therapy.
  • Radiation oncology
    The medical specialty that deals with treating cancer and other diseases with radiation.
  • Radiation therapy
    The careful use of various forms of radiation to treat cancer and other diseases.
  • 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.
  • Systemic radiation therapy
    The use of radioactive isotopes that can travel throughout the body to treat certain cancers.
  • Treatment plan
    A radiation oncologist's prescription describing 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.
  • Tumor
    abnormal lump or mass of tissue.


© 2014 Medical College of Wisconsin
Page Updated 09/08/2014