What Is Radiation Therapy?

Radiation therapy is the treatment of cancer and other diseases with ionizing radiation. Ionizing radiation deposits energy that injures or destroys cells in the area being treated (the "target tissue") by damaging their genetic material and making it impossible for these cells to continue to grow. Although radiation damages both cancer cells and normal cells, the normal cells are able to repair themselves and function properly.

What to Expect


Once you have been referred to radiation therapy you will meet with the radiation oncologist to discuss your simulation appointment, treatment plans and potential side effects.

  • Bring all recent imaging results, current medications, and any insurance information.
  • If available, please bring with you a family member or designated caregiver.
  • Allow for one to two hours for total visit time.

If radiation has been deemed a treatment option you will be given a subsequent appointment for radiation simulation.

  • It is very important to clarify with radiation staff if a certain diet is needed prior to the radiation simulation.
  • If you have issues with anxiety in close spaces or with previous imaging, please inform your treating physician in advance so that actions may be taken to ensure you do not experience these during CT simulation.


The simulation procedure will be the first step of radiation therapy. You should expect this appointment to last two hours.

During this procedure, the radiation therapist will place you in treatment position and obtain CT images of the treatment area. The therapists will place a small mark on your skin to mark the designated alignment position. This tattoo will be the size of a freckle. Additional marks will be placed on your skin to allow for reproduction of treatment position. Do not wash off these marks. Should you lose them, please notify your treatment team.

Upon completion of CT simulation, you will be given an appointment to start your radiation treatment approximately three days after your simulation. Your radiation therapist will schedule your appointments.


Your daily treatments will take approximately 15-30 minutes depending on the complexity of treatment. Treatment days are, Monday through Friday. The radiation oncologist will also meet with you once weekly. Please plan to spend additional time for this visit.  It is important to bring all medications to weekly appointments. Also, if available, please bring friend, family member, or designated caregiver.

See Types of Radiation Therapy.

Precautions During Treatment

Diet and Exercise

  • Get plenty of rest. Treatments may cause you to be tired after a few weeks.
  • An alternate to rest can include a brisk walk of 15-20 minutes which can help reduce fatigue as well.
  • Maintain a balanced diet. Avoid weight loss diets during your treatment. If applicable, please avoid foods heavy in spice, fried foods, or foods with sharp edges.


  • Do not remove the marks placed on your skin. Showers are recommended for daily hygiene. Allow water to run over the marks. Avoid using soap in the area. Pat the area dry. Soaps with alcohol are NOT recommended. Fragrance free Dove or Tone are safe.
  • The marks may rub off on clothing, therefore old undergarments or t-shirts are suggested to avoid staining newer clothing.
  • Avoid swimming, Jacuzzi and any activity that will cause you to perspire, which will cause the marks to fade.
  • Deodorant may be used.
  • Do not shave with razor the treated area.. This can cause skin irritation. If needed please use electric razor. **TALK TO YOUR DOCTOR ABOUT SHAVING BEARD OR CUTTING HAIR PRIOR TO ANY ADJUSTMENT AS THIS MAY RESULT IN COMPLICATIONS WITH RADIATION TREATMENT.

Other Precautions

  • If designated area includes region of interest you doctor may ask you to have oral cleansing solution or perhaps designated bathes during treatment. Please confirm with your treating physician or nurse about required upkeep.
  • Protect the treatment area from sun exposure during treatment.
  • Inform your radiation oncologist of all medications you are taking.
  • Inform your radiation oncologist if you experience a sore throat, as part of the esophagus may be in the treatment field.