Internal radiation therapy (brachytherapy)

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was updated on December 13, 2022.

During brachytherapy, or internal radiation therapy (IRT), radioactive material is placed into a catheter or another implantable device, which carries the radiation directly into or near a tumor. Implanting the device is generally painless, and the implants may be temporary or permanent. A variety of cancers may be treated with brachytherapy, including prostate cancer, a variety of gynecologic cancers and, in rare cases, head and neck or other cancers.

Intraoperative radiation therapy (IORT) is a form of brachytherapy that delivers a concentrated dose of radiation to the site of a tumor during surgery. IORT may help reduce side effects and the need for additional radiation treatments.

What is brachytherapy?

Brachytherapy is cancer treatment that involves placing a radiation source inside the body near cancerous tissue. This form of internal radiation therapy allows for more targeted radiation treatment, designed to reduce the size of tumors and kill cancer cells.

Brachytherapy allows for a precise treatment in only a few minutes. It offers a quicker, more effective type of radiation treatment for some patients than traditional radiation delivered in smaller doses over a longer period of time. For many cancer types, the entire brachytherapy treatment takes one to two days, instead of five to seven weeks for external beam radiation therapy (EBRT). Depending on the type and stage of cancer, brachytherapy may be combined with other treatments, which can vary treatment times.

How is brachytherapy implanted?

The care team will typically insert brachytherapy into the patient’s body through a catheter or an applicator, depending on the cancer type, using one of the following techniques:

  • Intracavitary brachytherapy: The care team places the radiation source directly in a body cavity, or a cavity that the surgical team creates. For instance, the radiation may be placed in the rectum to treat rectal cancer.
  • Interstitial brachytherapy: The care team places the radiation source directly in or near the tumor rather than in a body cavity. For instance, the radiation may be placed next to a tumor in the breast to treat breast cancer.
  • Episcleral brachytherapy: The care team attaches the radiation source to the patient's eye to treat ophthalmic tumors.

After the catheter or applicator has been placed, it’s used to deliver the radiation source. Typically, devices such as pellets, seeds, ribbons, wires, needles, capsules, balloons and tubes are used to carry the radioactive material. These implants remain in place for a set period of time depending on the cancer type, other treatments, the type of radiation source, the cancer’s location and the patient’s overall health status.

Types of brachytherapy

High-dose rate (HDR) brachytherapy

This internal radiation therapy delivers a high-dose of radiation from implants placed close to, or inside, the tumor(s) in the body in a short burst lasting a few minutes. Before each treatment, we check the position of the catheters with millimeter precision. Next, a radioactive pellet is inserted into each catheter sequentially. Computer guidance controls how far the pellet goes into the catheter to precisely target the location of tumors, and how long the pellet stays in the catheter to release its radiation dose. With a few well-placed catheters, HDR brachytherapy can provide a precise treatment that takes only a few minutes. Brachytherapy offers a quicker, more effective type of radiation treatment for some patients.

Low-dose brachytherapy (LDR)

Also sometimes called permanent seed implants, LDR brachytherapy uses radioactive seeds permanently implanted into the organ. These pellets emit low levels of radiation for several weeks. When this radiation treatment ends, the harmless seeds are left in place permanently. Primarily used to treat prostate cancer, LDR brachytherapy is a one-time procedure performed on an outpatient basis. The procedure itself generally takes about an hour. Brachytherapy offers a quicker type of radiation treatment for some patients. 

What is IORT?

With IORT, which stands for interoperative radiation therapy, a radiation oncologist delivers a large dose of radiation in a single treatment session during a surgical procedure. A patient must be a surgical candidate to be eligible for IORT. This treatment is generally reserved for individuals with early-stage disease.

Advantages of IORT include:

Efficient dosing. IORT delivers a concentrated dose of radiation to a tumor site immediately after a tumor is removed, helping to destroy the microscopic tumor cells that may be left behind.

Helps spare healthy tissues and organs. During IORT, a radiation oncologist applies a precise radiation dose while shielding healthy tissues or structures, such as the skin, that may be damaged using other techniques.

Shortened treatment times. IORT may help reduce the need for additional radiation therapy, which is typically given over weeks.

A "boost" for traditional radiation patients. Patients who must receive radiation therapy after surgery may receive a boost of radiation during IORT, allowing more time to recover from surgery before continuing radiation therapy.

What types of cancer are treated with brachytherapy?

Brachytherapy is a treatment option for several types of cancer. It may be the primary treatment or the primary method of delivering radiation therapy for some cancer types, while other cancers are treated with brachytherapy only in particular circumstances. According to the American College of Radiology and the Radiological Society of North America, among the more common cancers that may be treated with brachytherapy are:

  • Breast cancer. While most breast cancer patients treated with radiation receive external radiation therapy, brachytherapy may be an option for some women, such as those who had breast-conserving surgery to excise the cancer without removing the whole breast.
  • Lung cancer. For patients with non-small cell lung cancer that is blocking or causing problems in the airway, brachytherapy is sometimes used as a palliative treatment to shrink the tumor and relieve symptoms.
  • Prostate cancer. Brachytherapy is usually a treatment option for men with early-stage prostate cancer. It may be used alone or in combination with external radiation.
  • Rectal cancer. Brachytherapy may be a treatment option for some patients with rectal cancer, although its results for rectal cancer treatment are still being studied.
  • Cervical cancer. Most stages of cervical cancer can be treated with brachytherapy, but it is rarely a standalone treatment. It’s usually used in conjunction with external radiation therapy and other treatments.
  • Head and neck cancers. Early-stage cancers of the lip and mouth may be treated with brachytherapy alone. For throat (pharyngeal) cancer and other more advanced head and neck cancers, brachytherapy is sometimes a supplemental treatment option.

Other cancers that may be treated with brachytherapy include:

Brachytherapy side effects

You may experience discomfort in the days after a brachytherapy procedure, but side effects related to the radiation often aren’t felt right away. When they start, they may increase gradually, peaking in severity about one to three weeks after the device is implanted. The exact timeline depends on the type of brachytherapy and the cancer’s location.

Side effects from brachytherapy are often less severe than from external radiation, but both therapies can cause:

  • Fatigue
  • Skin irritation

Brachytherapy can also cause tenderness and swelling around the implantation site. Other, more specific side effects vary depending on the site of the cancer. For example:

  • Brachytherapy for breast cancer may lead to redness and bruising near the treatment site.
  • Brachytherapy for prostate cancer may cause rectal pain, diarrhea, urinary incontinence and erectile dysfunction.
  • For cervical cancer and other cancers in the female reproductive organs, brachytherapy may lead to vaginal dryness, painful sexual intercourse, urinary and bowel problems.

While most side effects of brachytherapy go away shortly after the treatment period, some can last for weeks, months or longer depending on individual circumstances, including the site of the cancer.

What to expect after brachytherapy

You generally won’t feel much pain during and after a procedure to place brachytherapy implants. You may be given a sedative or general anesthesia. Once the radiation device has been implanted, you may feel some discomfort or tenderness around the area.

Some patients go home soon after their procedure, while others need to stay at the hospital for a few days. The exact timeline depends on the type of brachytherapy and whether the implants are temporary or permanent.

If you receive permanent LDR brachytherapy with small implants, you may be able to go home after the procedure. After a few weeks or months, these implants will no longer give off radiation.

With HDR brachytherapy, treatment may be given once a week over a couple of weeks, but some patients receive multiple treatments a day, possibly over a couple of days, in which case they stay in the hospital until it’s completed.

Brachytherapy precautions

The radiation emitted by a brachytherapy device doesn’t travel far and generally affects only the site of the implant. Still, you will likely need to take some precautions, such as avoiding people during treatment in certain situations. If you are in the hospital with internal active radiation, you will likely be placed in a private room and may not be able to have visitors. Pregnant women and young children, who are particularly vulnerable to radiation, are generally banned from any visits during this time. However, if your implants are temporary, the radiation source is removed before you go home, making it safe for you to interact with others.

If you get permanent implants and are allowed to go home, ask your care team what safety precautions to follow. You may be told to stay away from pregnant women and children for some time. Also, if you’re planning any travel, consider asking your doctor for a note that explains your treatment in case an airport security system detects the radiation.

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Show references
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