Stereotactic Body Radiotherapy (SBRT) for Cancer

Cross section of skin showing high-energy radiation waves penetrating to reach a tumor.

Stereotactic body radiotherapy (SBRT) is a form of radiation therapy that is used to treat cancer. Your healthcare provider may suggest SBRT if your cancer cannot be treated with surgery or other methods. SBRT may be used to help cure or control the growth of your cancer. Or, it may be used to help reduce pain and other symptoms caused by your cancer. This sheet tells you more about SBRT and what to expect. If you have more questions about the treatment, talk with your healthcare provider.

How SBRT Works

SBRT uses strong  X-rays to destroy cancer cells. Imaging studies are used to get very clear pictures of the tumor. Then a machine called a linear accelerator (linac) is aimed at the tumor. It sends high doses of X-rays into the tumor. This can help kill cancer cells or slow their growth. It can also shrink the size of the tumor. Each radiation dose is precisely aimed so that normal tissue around the tumor receives little or no radiation. This helps reduce the risk of side effects.

Preparing for Your Treatment

SBRT is performed by a radiation therapy team. This team often includes a radiation healthcare provider, nurse, radiation therapist, physicist, and dosimetrist. Before your treatment begins, you’ll have one or more visits with your team to plan and prepare for your treatment. This may involve having other tests and procedures done. Prior to your first treatment session:

  • You may need to have fiducial markers (also called seeds) placed in or near the tumor site. The markers are tiny pieces of gold metal. They show up clearly on imaging studies and are used later to help guide your radiation treatment. Your healthcare provider will explain this procedure to you in more detail if it is needed.

  • You may have scans or other imaging tests done. These are used to map out the exact sites in your body that will be treated.

  • You may have things made that will help hold your body in the same position for each treatment session. These can include molds, masks, rests, and cushions.

Having SBRT Treatments

With SBRT, one to five doses are given over the course of one to two weeks. You and your team will discuss the exact schedule for your treatment in advance. Each treatment session takes about 60 to 90 minutes. Here’s what to expect during each session:

  • You change into a patient gown. The radiation therapist positions you on the treatment table. If positioning devices were made, they are used at this time.

  • The therapist leaves the room and turns on the machine from outside. He or she watches you on a TV monitor. You and the therapist can speak through an intercom.

  • X-ray or other scan images are used to make sure that the beams from the machine are positioned and lined up correctly with your body. The beams are then directed at the tumor. You will hear the machine, but you won’t feel anything.

  • You can go home shortly after the treatment is done. Your healthcare provider or nurse will let you know if and when you need to return for your next session.

Possible Side Effects of SBRT

With any form of radiation therapy, healthy cells and tissue around the tumor can also be affected by the treatment. This can lead to side effects, such as fatigue and skin changes. Most side effects go away soon after treatment ends. But some side effects do not occur until months or even years after the treatment. The type of side effects you have and how severe they are will depend on the amount of radiation you get and the part of your body being treated. Your healthcare provider can tell you more about what side effects to expect and how to manage them. If needed, your healthcare provider may give you medicines to treat some side effects. Your healthcare team can also teach you ways to help cope with the side effects.

When to see your healthcare provider

Call your healthcare provider if you have any of the following:

  • Fever of 100.4 ºF (38 ºC) or higher, or as directed by your healthcare provider

  • Shortness of breath or trouble breathing

  • Tiredness that doesn’t go away between treatments

  • Pain that doesn’t go away, especially if it’s in the same place

  • A new or unusual lump, bump, or swelling

  • Dizziness or lightheadedness

  • Unusual rashes, bruises, or bleeding

  • Uncontrolled nausea and vomiting

  • Diarrhea that doesn’t improve over time

  • Skin breakdown or severe pain due to skin irritation

  • Any new or concerning symptom


You’ll have one or more follow-up visits with your healthcare provider. These allow your healthcare provider to check your health and the progress of your treatment. If more tests or treatments are needed, your healthcare provider will discuss these with you.