Intensity Modulated Radiotherapy (IMRT)


What is IMRT?

IMRT is a type of radiation therapy that varies the intensity of radiation beams, allowing stronger doses to reach specific tumor areas. It’s often combined with IGRT, which uses detailed scans taken before each radiation treatment to narrowly target tumors. Together, these therapies help Mercy cancer specialists treat tumors with greater precision, causing less damage to nearby healthy tissues.

How Does IMRT Work?

Traditional radiation therapy uses radiation beams of uniform intensity to destroy tumor cells. With IMRT, special software is used to vary the intensity of each radiation beam. This means the highest doses of radiation reach your tumor instead of healthy tissue. Beams can also rotate around you, aiming radiation at your tumor from the best angles and locations.

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

Benefits of IMRT

IMRT is a treatment option with several advantages, including:

  • Shapes radiation intensity to the unique size and shape of your tumor
  • Accurately delivers high-dose radiation, potentially increasing treatment effectiveness
  • Avoids radiation of healthy organs and tissues, reducing side effects and complications
Coordinated Radiation Oncology Care

Treating the whole patient requires a whole team. At Mercy, your radiation oncology team includes oncologists, physician assistants, radiation therapists, nurses, medical physicists, dosimetrists and other professionals who provide coordinated care and support.

What to Expect From IMRT Treatment

Your Mercy care team provides an outpatient treatment schedule, which typically includes daily treatments over five to eight weeks. Each treatment session lasts about an hour.

When you arrive for each session, you’ll be taken to the treatment room, where a Mercy radiation therapist will help you get positioned. You’ll most likely lie on your back, and the therapist may fit you with a device to help you remain still during treatment. Tiny markings may be made on your skin to line up equipment with the treatment area.

You’ll move through the machine once for pre-treatment imaging. Based on these images, your radiation plan or position may be adjusted. Then, you’ll move through the machine again slowly as customized IMRT treatment is delivered.

IMRT is noninvasive and as painless as a CT scan or x-ray.

Side Effects & Risks of IMRT

IMRT can cause temporary side effects like fatigue, nausea or skin irritation. You may also have side effects in the area treated with radiation. For example, if your cancer is in your head, you may have headaches, hair loss or dry eyes.

Most side effects go away after treatment ends, but it’s possible to have long-lasting effects or experience them months or years later. Talk with your Mercy care team about potential side effects and ways to manage them.

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