Brachytherapy: The Basics

Author: Courtney Misher, MPH, BS R.T.(T)
Last Reviewed: January 25, 2024

There are two main ways of giving radiation therapy. It can either be given from outside of the body (external beam radiation therapy or EBRT) or from inside the body (internal radiation therapy or brachytherapy). Patients can receive one type of radiation or both types of radiation as part of their treatment plan.

What is brachytherapy?

Brachytherapy is a type of radiation therapy that is given inside the body. Radioactive material is put either into or near the tumor. The material may be left in your body or taken out. The tissues closest to the radioactive material receive the most radiation. The tissues further away receive less radiation. Brachytherapy delivers a higher dose of radiation in a shorter period of time than external beam radiation. This results in less damage to healthy tissues compared to EBRT.

What type of cancer is brachytherapy used to treat?

Brachytherapy can be used to treat cancers of the:

  • Uterus, cervix, and vagina.
  • Prostate.
  • Head and neck.
  • Breast.
  • Lung.
  • Thyroid.
  • Eye.

In some cases, bracashytherapy is used to prevent your tumor from coming back after it has been removed with surgery. This is the case with some sarcomas.

What type of radioactive material is used for brachytherapy?

There are a few radioactive materials that are used to give brachytherapy treatments. The most common materials used are:

  • Cesium-131.
  • Iridium-192.
  • Iodine-125.
  • Palladium-103.

In most cases, the radioactive substance is "sealed" in small containers (such as seeds, pellets, thin wires, or tubes).

How is brachytherapy put in place?

This depends on the type of cancer you have. Brachytherapy can be placed using catheters (small, hollow, and stretchy tubes), needles (small, hollow, non-stretchy tubes), or an applicator (larger, hollow device). The catheters or applicator will be put into your body, either in the operating room or in the radiation treatment room. Ways of putting brachytherapy in your body:

  • Intracavity brachytherapy: Radiation is put into a body cavity or cavity from surgery. For example, radiation can be put into the windpipe to treat lung cancer or into a woman’s vagina to treat cervical or endometrial cancer.
  • Interstitial brachytherapy: Radiation is put into or near the tumor. For example, radiation is placed in the prostate gland for prostate cancer.
  • Systemic radiation therapy: Radioactive material is "unsealed" and is taken by mouth or injected into the bloodstream, where it travels through the body to the cancer. For example, a radioactive iodine (I-131) pill can be taken to treat thyroid cancer.

Your care team may use CT scans, MRI scans, or Ultrasound to guide the placement of the catheters or applicator.

High-Dose Rate (HDR) Brachytherapy Versus Low-Dose Rate (LDR) Brachytherapy.

Radiation can be given quickly in a few minutes, can be left in the body for a few days, or can be put in your body and never removed. The type of brachytherapy you will get will depend on where your cancer is, how much it has grown, your overall health, and the treatment goals.

  • HDR brachytherapy: The radioactive material is put into your body for a short time. The amount of time is based on the dose of radiation needed. This can be as little as a few minutes or up to 20 minutes. The radioactive material is then removed, and you can go home. If the catheter or applicator is used for your treatment needs to stay in place, then you will need to stay in the hospital until the end of your planned treatments. You are not radioactive after the radioactive material is removed.
  • LDR brachytherapy: The radioactive material is put into your body and releases a low dose of radiation over a period of several hours to days. In most cases, this is done during a stay in the hospital. While the material is in your body, you are putting off radiation. Ask your provider if you can have visitors. Once the dose of radiation has been received, the radioactive material is removed from your body. Once it is removed, you are safe to have visitors and will likely go home.
  • Permanent brachytherapy (also a type of LDR brachytherapy): Is often used in treating prostate cancer. The radioactive material is put into your body and left there. The radioactive material used will stop putting off radiation over a period of time. You may need to limit close contact with children and pregnant women. Ask your provider what precautions you need to take and for how long.

Resources For More Information

ACR, R. S. N. A. and. (2023). Brachytherapy. Retrieved from

American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer, Cooper, D. S., Doherty, G. M., Haugen, B. R., Kloos, R. T., Lee, S. L., et al. (2009). Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid : 19(11), 1167-1214.

American Thyroid Association Taskforce On Radioiodine Safety, Sisson, J. C., Freitas, J., McDougall, I. R., Dauer, L. T., Hurley, J. R., et al. (2011). Radiation safety in the treatment of patients with thyroid diseases by radioiodine 131I : Practice recommendations of the American thyroid association. Thyroid : 21(4), 335-346.

Brachytherapy for cancer. National Cancer Institute. (2019, January 29). Retrieved from

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