Internal Radiation Therapy for Cancer

Doctor talking with her patient in an examining room
Credit: iStock

In internal radiation therapy, a source of radiation is put inside your body. The radiation source can be solid or liquid.

Types of Internal Radiation Therapy

Internal radiation therapy with a liquid source is called systemic therapy. Systemic means that the treatment travels in the blood to tissues throughout your body, seeking out and killing cancer cells. You receive systemic radiation therapy by swallowing, through a vein via an IV line, or through an injection.

A systemic radiation therapy called radioactive iodine, or I-131, is most often used to treat certain types of thyroid cancer.

Another type of systemic radiation therapy, called targeted radionuclide therapy, is used to treat some patients who have advanced prostate cancer or gastroenteropancreatic neuroendocrine tumor (GEP-NET). This type of treatment may also be referred to as molecular radiotherapy.

Internal radiation therapy with a solid source is called brachytherapy. In this type of treatment, seeds, ribbons, or capsules that contain a radiation source are placed in your body in or near the tumor. Like external beam radiation therapy, brachytherapy is a local treatment and treats only a specific part of your body.

Brachytherapy is often used to treat cancers of the head and neck, breast, cervix, prostate, and eye.

What to Expect When Having Internal Radiation Therapy

What Happens Before Your First Internal Radiation Therapy Treatment

You will have a 1- to 2-hour meeting with your doctor or nurse to plan your treatment before you begin internal radiation therapy. At this time, you will have a physical exam, talk about your medical history, and maybe have imaging tests. Your doctor will discuss the type of internal radiation therapy that is best for you, its benefits and side effects, and ways you can care for yourself during and after treatment. You can then decide whether to have internal radiation therapy.

How Brachytherapy Is Put in Place

Most brachytherapy is put in place through a catheter, which is a small, stretchy tube. Sometimes, brachytherapy is put in place through a larger device called an applicator. The way the brachytherapy is put in place depends on your type of cancer. Your doctor will place the catheter or applicator into your body before you begin treatment.

Techniques for placing brachytherapy include:

  • Interstitial brachytherapy, in which the radiation source is placed within the tumor. This technique is used for prostate cancer, for instance.
  • Intracavity brachytherapy, in which the radiation source is placed within a body cavity or a cavity created by surgery. For example, radiation can be placed in the vagina to treat cervical or endometrial cancer.
  • Episcleral brachytherapy, in which the radiation source is attached to the eye. This technique is used to treat melanoma of the eye.

Once the catheter or applicator is in place, the radiation source is placed inside it. The radiation source may be kept in place for a few minutes, for many days, or for the rest of your life. How long it remains in place depends on the type of radiation source, your type of cancer, where the cancer is in your body, your health, and other cancer treatments you have had.

Types of Brachytherapy

There are three types of brachytherapy:

  • Low-dose rate (LDR) implants: In this type of brachytherapy, the radiation source stays in place for 1 to 7 days. You are likely to be in the hospital during this time. Once your treatment is finished, your doctor will remove the radiation source and the catheter or applicator.
  • High-dose rate (HDR) implants: In this type of brachytherapy, the radiation source is left in place for just 10 to 20 minutes at a time and then taken out. You may have treatment twice a day for 2 to 5 days or once a week for 2 to 5 weeks. The schedule depends on your type of cancer. During the course of treatment, your catheter or applicator may stay in place, or it may be put in place before each treatment. You may be in the hospital during this time, or you may make daily trips to the hospital to have the radiation source put in place. As with LDR implants, your doctor will remove the catheter or applicator once you have finished treatment.
  • Permanent implants: After the radiation source is put in place, the catheter is removed. The implants remain in your body for the rest of your life, but the radiation gets weaker each day. As time goes on, almost all the radiation will go away. When the radiation is first put in place, you may need to limit your time around other people and take other safety measures. Be extra careful not to spend time with children or pregnant women.

What to Expect When the Catheter Is Removed

Once you finish treatment with LDR or HDR implants, the catheter will be removed. Here are some things to expect:

  • You will get medicine for pain before the catheter or applicator is removed.
  • The area where the catheter or applicator was might be tender for a few months.
  • There is no radiation in your body after the catheter or applicator is removed. It is safe for people to be near you-even young children and pregnant women.

For a week or two, you may need to limit activities that take a lot of effort. Ask your doctor what kinds of activities are safe for you and which ones you should avoid.

Internal Radiation Therapy Makes You Give Off Radiation

With systemic radiation, your body fluids (urine, sweat, and saliva) will give off radiation for a while. With brachytherapy, your body fluids will not give off radiation, but the radiation source in your body will. If the radiation you receive is a very high dose, you may need to follow some safety measures. These measures may include:

  • Staying in a private hospital room to protect others from radiation coming from your body
  • Being treated quickly by nurses and other hospital staff. They will provide all the care you need, but may stand at a distance, talk with you from the doorway of your room, and wear protective clothing.

Your visitors will also need to follow safety measures, which may include:

  • Not being allowed to visit when the radiation is first put in
  • Needing to check with the hospital staff before they go to your room
  • Standing by the doorway rather than going into your hospital room
  • Keeping visits short (30 minutes or less each day). The length of visits depends on the type of radiation being used and the part of your body being treated.
  • Not having visits from pregnant women and children younger than a year old

You may also need to follow safety measures once you leave the hospital, such as not spending much time with other people. Your doctor or nurse will talk with you about any safety measures you should follow when you go home.

What To Know About Brachytherapy (A Type of Internal Radiation Therapy)
(Type: MP3 | Time: 3:17 | Size: 3.1MB)

  • Updated: May 1, 2018

If you would like to reproduce some or all of this content, see Reuse of NCI Information for guidance about copyright and permissions. In the case of permitted digital reproduction, please credit the National Cancer Institute as the source and link to the original NCI product using the original product's title; e.g., “Internal Radiation Therapy for Cancer was originally published by the National Cancer Institute.”

We welcome your comments on this post. All comments must follow our comment policy.