Overview

Brachytherapy (brak-e-THER-uh-pee) is a type of radiation therapy used to treat cancer. It places radioactive material in or near the cancer inside the body. This is sometimes called internal radiation.

Another type of radiation therapy, called external beam radiation therapy (EBRT), is more common than brachytherapy. During EBRT, a machine moves around you and directs beams of radiation to specific points on the body.

Radiation therapy uses powerful sources of energy to damage or kill cancer cells. As part of cancer treatment, it can help shrink tumors. And it can help lower the risk of the cancer coming back.

Brachytherapy allows your healthcare team to use a higher total dose of radiation on a smaller, targeted area. This lowers the risk of damage to healthy tissue nearby.

Types

There are two types of brachytherapy:

  • High dose rate (HDR) brachytherapy delivers a higher dose of radiation over a short time. The radioactive material is inserted, typically left in place for a few minutes and then removed. Treatment may involve a few sessions.
  • Low dose rate (LDR) brachytherapy typically uses small radiation seeds, about the size of a grain of rice. These are implanted into the tumor. The seeds deliver a lower dose of radiation over several months until the radiation is gone. The seeds stay permanently in the body. They are not harmful. LDR brachytherapy is a common treatment for prostate cancer.

Why it's done

Brachytherapy is most often used to treat cancer. Sometimes, it may be used to treat other conditions, such as heart conditions.

As part of cancer treatment, brachytherapy can be an alternative to external beam radiation therapy in some situations. It may be used on its own or with other cancer treatments. For example, brachytherapy sometimes is used after surgery to destroy any remaining cancer cells. Brachytherapy also can be used as an extra boost of radiation with external radiation.

Brachytherapy is used to treat many types of cancer. Some examples include:

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Risks

Side effects of brachytherapy are specific to the area being treated. Because brachytherapy focuses radiation in a small treatment area, only that area is affected.

Common side effects

Depending on the area being treated, side effects may include:

  • Tenderness and swelling in the treatment area.
  • Some discomfort or pain.
  • Changes in urination and the passing of stool.
  • Bleeding or spotting.
  • Changes in sexual function with treatment of reproductive areas.
  • Infection.

These side effects typically are mild and short-term. Ask your healthcare team what you may expect from your treatment.

Rare complications

Serious complications can sometimes occur, but these are rare. They may include:

  • An opening, called a fistula, into nearby organs.
  • Changes to tissue in or around the treatment area. Sometimes, brachytherapy can cause tissues in the area to stiffen or narrow. On occasion, it can keep wounds from healing or cause tissue to die.

How you prepare

Before you begin brachytherapy, you:

  • Meet with your radiation oncologist. This is a doctor who specializes in treating cancer with radiation. Your radiation oncologist oversees your brachytherapy treatment.
  • Have imaging tests. You have imaging scans done to help plan your treatment. These may include X-rays, MRIs or CT scans. The images help your radiation oncologist and other members of the care team decide the dose and positioning of the radiation. You have these tests either before your procedure or at the start of your procedure.
  • Plan for anesthesia. You and your healthcare team may talk about anesthesia for you during the procedure. Anesthesia can be conscious sedation or general anesthesia. Conscious sedation means you are awake during the procedure but feel no pain. General anesthesia means you sleep through the procedure. Some procedures don't require anesthesia. It depends on your cancer and the type of brachytherapy planned for you.
  • Follow your care team's instructions. Your care team gives you instructions on how to prepare. Instructions include whether you need to stop eating or drinking. They also include whether you need lab tests and, if so, whether you need to change how you take your medicine that day.

What you can expect

Typically, you receive brachytherapy as an outpatient, which means you go home the same day as your treatment. Depending on the treatment plan, you may have a hospital stay.

HDR brachytherapy

During HDR brachytherapy, the radioactive material is inserted for a short time and then removed.

  • Positioning. At the start of the procedure, your care team helps you into a comfortable position in the treatment room. You may receive anesthesia at this time.
  • Placement of the device. Your radiation therapy team places a radiation delivery device in or near the cancer. Delivery devices may look different depending on the treatment area. For vaginal cancers, the delivery device may be a tube or cylinder made to fit the specific body opening. For cancers of the breast or prostate, the device may consist of needles or special applicators inserted directly into body tissue. Sometimes, narrow flexible tubes called catheters connect the device to a radiation delivery machine.
  • Imaging. CT scans, ultrasounds or other imaging tests help guide the devices into place. The images help make sure that the treatment is in the right spot.
  • Planning. Your radiation therapy team uses computer software to create your custom treatment plan. The plan details where the radiation doses are given along the path of the brachytherapy device. Planning often is done while you wait in the room. Planning can take some time, up to a few hours. Time depends on the type of cancer and the treatment.
  • Radiation delivery. The radiation therapy team leaves the room. The radioactive material is inserted into the delivery device with the help of a machine. The team members observe from a nearby room where they can see and hear you. If you are awake and have any concerns or do not feel comfortable, tell the team. The radioactive material stays in your body for several minutes. You won't feel the radiation. It doesn't hurt or burn.
  • Removal of the radioactive material. When the session is finished, the radioactive material is taken out. After the radioactive material is removed from your body, you won't give off radiation. You are not radioactive. You aren't a danger to other people, and you may go on with your usual activities.

You may have more than one session a day over a number of days. The delivery device may stay in place until treatment is finished. Or it may be taken out and placed again at each session.

LDR brachytherapy

LDR brachytherapy typically is permanent. Radioactive seeds that do not need to be taken out later are placed inside the body. Radiation from the seeds is released to the surrounding area at a low dose rate over several months. It eventually fades away.

  • Placement of the seeds. While you are under anesthesia, your radiation oncologist uses thin, hollow needles to implant the radioactive seeds in or near the cancer. An imaging test, such as ultrasound or CT, often is used to make sure the seeds are in the right place. You should not feel any discomfort once the seeds are in place.
  • After the procedure. The seeds continue to give off radiation for a short amount of time. This radiation usually stays near the treatment area. It is not likely that people around you are affected. As a precaution, your healthcare team may advise you to limit for a few days the time you spend around children and anyone who is pregnant. The amount of radiation in your body becomes lower over time.

Results

Your healthcare team may recommend imaging tests or physical exams after brachytherapy. Follow-up testing can help show whether treatment was a success. Testing also can help guide next steps in your treatment. The types of scans and exams you have depend on the type and location of your cancer.

During follow-up exams, your team asks you about possible side effects. Let team members know if you have any symptoms. Team members usually can help you find ways to feel better.

Call your care team if you have:

  • Fever or chills, which can be a sign of infection. A fever is a temperature greater than 100.4 degrees Fahrenheit (38 degrees Celsius).
  • Heavy bleeding.
  • Pain that gets worse, even with medicine.
  • Any other side effects that you did not expect.
April 16, 2026
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