Internal Radiation Therapy (Brachytherapy)

Internal radiation is also called brachytherapy. A radioactive implant is put inside the body in or near the tumor. Getting the implant placed is usually a painless procedure. Depending on your type of cancer and treatment plan, you might get a temporary or a permanent implant.

What is internal radiation therapy?

Internal radiation therapy (brachytherapy) allows a higher dose of radiation in a smaller area than might be possible with external radiation treatment. It uses a radiation source that’s usually sealed in a small holder called an implant. Different types of implants may be called pellets, seeds, ribbons, wires, needles, capsules, balloons, or tubes. No matter which type of implant is used, it is placed in your body, very close to or inside the tumor. This way the radiation harms as few normal cells as possible.

  • During intracavitary radiation, the radioactive source is placed in a body cavity (space) , such as the rectum or uterus.
  • With interstitial radiation, the implants are placed in or near the tumor, but not in a body cavity.

How are implants placed in the body?

The implant procedure is usually done in a hospital operating room designed to keep the radiation inside the room. You’ll get anesthesia, which may be either general (where drugs are used to put you into a deep sleep so that you don’t feel pain) or local (where part of your body is numbed).

One or more implants is put into the body cavity or tissue with an applicator, usually a metal tube or a plastic tube called a catheter. Imaging tests (an x-ray, ultrasound, MRI, or CT scan) are usually used during the procedure to find the exact place the implant needs to go.

Before being placed, implants are kept in containers that hold the radiation inside so it can’t affect others. The health professionals handling the implants may wear special gear that protects them from exposure once the implants are taken out of the container.

How long do implants stay in place?

The length of time an implant is left in place depends on the type of brachytherapy you are getting. Some implants are permanent, while others are taken out after a few minutes or days. The type of implant you get will depend on the kind of cancer, where it is in your body, your general health, and other treatments you have had.

High-dose rate brachytherapy

High-dose-rate (HDR) brachytherapy allows a person to be treated for only a few minutes at a time with a powerful radioactive source that’s put in the applicator. The source is removed after several minutes. This may be repeated over the course of a few days to weeks. The radioactive material is not left in your body. The applicator might be left in place between treatments, or it might be put in before each treatment.

Low-dose-rate brachytherapy

In this approach, the implant gives off lower doses of radiation over a longer period.

Some implants are left in from 1 to a few days and then removed. You’ll probably have to stay in the hospital, sometimes in a special room, during treatment. For larger implants, you might have to stay in bed and lie still to keep it from moving.

Some smaller implants (such as the seeds or pellets) are left in place – they’re never taken out. Over the course of several weeks they stop giving off radiation. The seeds are about the size of rice grains and rarely cause problems. If your implants are to be left in, you may be able to go home the same day they’re put in.

How will I feel during implant therapy?

You’re not likely to have a lot of pain or feel sick while implants are being put in. The drugs used while they’re being placed might make you feel drowsy, weak, or sick to your stomach, but these side effects don’t last long. If your implant is held in place by an applicator, you may have some discomfort in that area. Ask for medicine to help you relax or to relieve pain if needed. Be sure to tell your cancer care team if you have  burning, sweating, or other symptoms.

What happens after a temporary implant is removed?

In most cases, anesthesia is not needed when the applicator and/or implant is removed. It’s usually done right in your hospital room. The treated area may be sore or tender for some time after treatment, but most people can return to normal activities quickly. Keep in mind that your body is recovering from radiation treatments, and you may need extra sleep or rest breaks over the next few days.

What happens to permanent implants?

The radioactive materials stop giving off radiation over time. It may take weeks or months. Talk to your cancer care team about how long it will take in your case. Once the radiation is gone, the implant(s) are no longer active. They usually stay in place and cause no harm, so there’s no need to take them out.

Will I be radioactive during or after internal radiation treatment?

With internal radiation therapy, your body may give off a small amount of radiation for a short time.

If you have a temporary implant, you’ll be asked to stay in the hospital and might have to limit visitors during treatment. You also may be asked to stay a certain distance away from them. Pregnant women and children might not be allowed to visit you. Once the implant is removed, your body will no longer give off radiation.

Over a few weeks to months, permanent implants will slowly stop giving off radiation. The radiation usually doesn’t travel much farther than the area being treated, so the chances that others could be exposed to radiation is very small. Still, your health care team might ask you to take certain precautions such as staying away from small children and pregnant women, especially right after you get the implants.  

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

American College of Radiology and the Radiological Society of North America. Brachytherapy. Accessed at on March 21, 2016.

Halperin EC, Perez CA, Brady LW (Eds). Principles and Practice of Radiation Oncology. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2013.

Last Medical Review: February 10, 2017 Last Revised: February 10, 2017

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