This page was reviewed under our medical and editorial policy by

Kevin King, MD, Radiation Oncologist, City of Hope | Downtown Chicago

This page was reviewed on December 22, 2023.

What is TomoTherapy?

TomoTherapy® is a form of image-guided radiation therapy that combines a form of intensity modulated radiation therapy (IMRT), with the accuracy of computed tomography (CT) scanning technology, in one machine. The combination of these technologies allows doctors to adjust the radiation beam to better match the location, size and shape of the tumor. This radiation therapy delivery system is designed to allow doctors to target tumors more precisely while sparing surrounding tissue and nearby organs.

Cancer Treatment Centers of America® (CTCA) is now City of Hope®, joining forces to expand patient access to personalized, comprehensive cancer care.

What types of cancer is TomoTherapy used for?

TomoTherapy may be an option to treat multiple cancers in various stages. Cancers treated with TomoTherapy include:

It also may be used to treat metastatic cancers and tumors that may be hard to reach with other technologies.

Advantages of TomoTherapy

Because it’s designed to allow doctors to sculpt the radiation treatment more accurately to the size, shape and location of the tumor, TomoTherapy offers several advantages. Among them:

  • More radiation is focused on the tumor and less on surrounding tissue.
  • Higher levels of radiation may be aimed directly at the tumor.
  • Patients may experience fewer side effects.

Some cancer patients who have reached their maximum tolerance dose of traditional radiation may be a candidate for TomoTherapy radiation.

How does TomoTherapy treatment work?

Undergoing TomoTherapy treatment may seem similar to having a CT scan or an X-ray.

When it’s time for the treatment, a radiation therapist helps the patient into position on the table. In most cases, the patient will be face up. The therapist typically places a device or devices to keep the patient still during the procedure.

Before the radiation treatment begins, the patient moves through the machine while a clinician uses scanning technology to capture a 3D image of the treatment area. This allows the radiation oncologist and radiation therapist to adjust the way the radiation is delivered if needed.

During treatment, the patient moves through the machine slowly as radiation is applied from 360 degrees. The patient may hear clicking, humming or other noises from the machine.

The procedure may take as little as 15 minutes and is painless.

Side effects and risks

Like other radiation therapy technologies, TomoTherapy may cause short-term side effects.

Some side effects may depend on the area of the body being treated. For instance, if radiation treatment was delivered to the head, side effects may include headaches, mouth sores, difficulty eating and dry eyes.

General side effects of TomoTherapy may include:

  • Redness, skin irritation or peeling
  • Fatigue
  • Nausea
  • Hair loss to the treated area

Most side effects of TomoTherapy subside shortly after treatments have stopped. Others may linger after treatment but tend to fade away over several months.

As with many cancer treatments, TomoTherapy may have some long-term side effects, such as skin changes or a slight risk of developing a second cancer.

TomoTherapy at City of Hope

Your care team at City of Hope will share information on potential short-term or long-term side effects of your treatment. They also may recommend supportive care services designed to help address side effects of your treatment, including:

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