Intensity Modulated Radiotherapy (IMRT)


Intensity-modulated radiation therapy (IMRT) is a type of radiation therapy that kills cancer cells inside your body. It allows your care team to match radiation beamlets to the unique shape of your tumor.

What is IMRT?

Before you begin IMRT, your doctor will order scans (pictures) of your cancer. These pictures help your doctor confirm the exact location of the cancer in your body. They also provide a 3-D map of your tumor.

IMRT uses a machine to send radiation into your body. It allows your doctor to shape the radiation to the contours of your tumor while sparing normal tissues near your tumor. Special computer software is used to control the intensity of each radiation beamlet. This means the highest doses of radiation hit your tumor instead of healthy tissue.

Because of its precision, IMRT is ideal for shrinking or destroying tumors next to vital organs. It is often used to treat cancers of the prostatebreastlung, gastrointestinal tract, brain and other structures in the head or neck.

Benefits of IMRT 

All types of radiation therapy kill cancer cells, but IMRT offers several advantages. These include:

  • More accurate radiation delivery that is shaped to your tumor.
  • Higher doses of radiation can be sent to the tumor, increasing the efficacy of treatment.
  • A markedly reduced amount of radiation reaches healthy organs and tissue next to the tumor. This helps reduce side effects and long-term complications.

What to Expect from IMRT Treatment

Your Mercy care team will make sure you understand what to expect before, during and after IMRT treatment. For example:

  • Some patients need to have tiny tattoos inked on their skin. These marks help your care team line up the radiation equipment with the treatment area.
  •  You may also need to use a custom-fit, molded device. It will help you get into the same position before each treatment, and stay still during treatment.
  • Like any form of radiation therapy, IMRT may cause temporary side effects. These often include fatigue and skin changes (such as redness, itching or peeling). You may also have side effects in the specific part of your body receiving radiation. For example, if your cancer is in your head, you may experience headaches and hair loss. Our team will make sure you're fully informed of possible side effects before you begin treatment. If your doctor recommends you have IMRT, it’s because he or she believes the benefits outweigh the risks. Your care team will carefully plan your treatments to ensure they are safe and effective.

If you have questions or concerns about IMRT, don’t hesitate to talk to one of your Mercy caregivers. Our goal is to get rid of your cancer, so you can get on with your life.

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