Image-Guided Radiation Therapy (IGRT)

What is image-guided radiation therapy (IGRT)?

Image-guided radiation therapy (IGRT) is a type of radiation therapy. This treatment kills cancerous cells and shrinks or eliminates cancerous tumors. You may need IGRT if you have cancer in an area of your body that moves during treatment. For example, a tumor in your lung may move when you take a breath. To make sure providers target treatment areas accurately, your radiation team needs to do specific daily targeting. IGRT makes it possible for your radiation team to do that.

IGRT is a type of external beam radiation therapy (EBRT). It uses a machine called a linear accelerator (LINAC). The machine directs targeted radiation in the form of high-energy X-ray/photon beams into cancerous cells and tumors to destroy them. The machine never touches your body.

Like other types of EBRT, image-guided radiation therapy uses the results of imaging tests to target cancerous cell areas or tumor masses. With IGRT, radiation oncologists take images before and during your treatment sessions. That way, they can immediately redirect radiation — if needed — so energy beams stay optimally focused on cancerous tumors and avoid nearby healthy tissue.

When do radiation oncologists use IGRT?

Radiation oncologists typically use IGRT to treat:

• Lung cancer.
• Prostate cancer.
• Brain cancer.
• Abdominal cancer.
• Gynecological cancer like ovarian cancer, uterine cancer or vaginal cancer.
• Head and neck cancer.

They often use IGRT together with other routine technologies for radiation therapy like intensity-modulated radiation therapy (IMRT) or stereotactic body radiotherapy (SBRT).

How should I prepare for IGRT?

If you’re having this treatment, your radiation oncologist will explain what happens before, during and after treatment. For example, they may do a treatment simulation. This is a session before your actual treatment when your team makes treatment plans.

They’ll use images and scans of your body, along with laser light-based accuracy measurements to tailor treatment exactly to your situation. Before simulation, your radiation oncologist and team will explain what will happen so you know what to expect. They’ll tell you if there’s anything you need to do before the simulation session.

What happens during image-guided radiation therapy?

Like other types of EBRT, you receive treatment while lying on a treatment table while a machine directs energy beams toward the tumor.

During your treatment sessions, your radiation oncologist or care team member will take new imaging scans and compare them with images taken during the treatment simulation process.

Image-guided radiation therapy may involve scans including:

• X-rays.
• Computed tomography (CT) scans.
• Magnetic resonance imaging (MRI) scans.
• Positron emission tomography (PET) scans.
• Ultrasound test.

Sometimes, the machine delivering radiation has built-in imaging equipment. Other times, your radiation oncology team may move the treatment table to imaging equipment in the treatment room.

How long does an image-guided radiation therapy session take?

Most IGRT treatments take 15 to 20 minutes, but there may be times when a session will last 30 minutes to an hour. In IGRT, your radiation therapy team may deliver radiation, then stop treatment to take imaging tests and compare those results with scans taken previously.

Based on that comparison, they may need to make changes in the beam or table position. They may change your position on the treatment table. Your radiation oncology team will explain what you can expect.

What are the benefits of image-guided radiation therapy?

This treatment is an effective, very safe way to treat cancerous tumors in areas of your body that move or require very exact targeting. Some research suggests additional imaging information and accuracy may expose you to a limited and tolerable amount of radiation than treatment that doesn’t use IGRT.

How long does it take to recover from image-guided radiation therapy?

Your recovery time depends on factors like your treatment schedule and radiation therapy side effects. Common IGRT side effects may include:

• Diarrhea.
• Fatigue.
• Nausea and vomiting.
• Skin changes like irritation and itchiness.

When should I call my healthcare provider?

Contact your provider if your side effects don’t seem to go away when you expected or if they’re more severe than you expected. Your radiation oncologist and clinical team will discuss any likely or possible side effects for your specific treatments before and during your radiation therapy course.

What’s the difference between IGRT and IMRT (intensity-modulated radiation therapy)?

Like IGRT, intensity-modulated radiation therapy (IMRT) involves using images of the tumor to plan treatment that targets the tumor while protecting nearby healthy tissue.

In IMRT, radiation oncologists input images into a computer program. The program uses the tumor’s dimensions to design treatment that uses multiple energy beams or a single beam.

In IGRT, radiation oncologists do imaging tests during treatment.

Your radiation oncologist may combine both therapy types to deliver radiation.

What’s the difference between IGRT and stereotactic body radiation therapy (SBRT)?

In stereotactic body radiation therapy (SBRT), your radiation oncologist plans treatment based on images they obtain during the treatment planning process.

In IGRT, they take images before and during treatment.

Image-guided radiation therapy, stereotactic radiation therapy and intensity-modulated radiation are all examples of advanced and precision technology types of external radiation treatment (EBRT).