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Radiation Therapy—Internal

(Ionizing Radiation; Radiotherapy; Brachytherapy)

En Español (Spanish Version)

Definition | Reasons for Procedure | Possible Complications | What to Expect | Call Your Doctor


Radiation therapy is used to treat cancer and other diseases. It uses high-energy particles to damage the DNA in the cancer cells. This makes the cells unable to grow or divide.

There are two main types of radiation therapy:

  • External —radiation is delivered by a machine that shoots particles at the cells from outside the body
  • Internal—radioactive materials are placed in the body near the cancer cells; this is also called implant radiation or brachytherapy

In certain cases, your doctor may recommend a combination of these. Radiation is often used with other types of treatment, such as surgery, chemotherapy, and immunotherapy, which stimulates the immune system to fight infection.

This fact sheet will focus on internal radiation therapy.

Reasons for Procedure

This procedure is done to:

  • Control the growth or spread of cancer
  • Attempt to cure cancer
  • Reduce pain or other symptoms caused by cancer—called palliative radiation

Radiation therapy is used to treat solid tumors such as prostate cancer, breast cancer, and head and neck cancers.

Possible Complications

Internal radiation can cause side effects. The radiation damages your own healthy cells as well as the cancer cells. The side effects will vary depending on the type and location of treatment. Common side effects of radiation include, but are not limited, to:

  • Fatigue
  • Skin changes such as redness and irritation
  • Reduced white blood cell count
  • Hair loss
  • Nausea, vomiting, or diarrhea
  • Appetite loss

Discuss the specific side effects that you may have with your doctor.

Factors that may increase the risk of complications include:

A woman who is pregnant or could be pregnant should avoid exposure to radiation. It could harm a developing fetus.

What to Expect

You may need local anesthesia, which will numb a small area, or general anesthesia, which keeps you asleep during the procedure.

The radiation source will be placed inside your body on or near the affected area. This provides higher doses of radiation in a shorter time. The radioactive sources are in the form of wires, seeds, or rods. This treatment is mostly used for cancers of the head and neck, breast, uterus, thyroid, cervix, and prostate. The two main types of internal radiation are:

  • Interstitial radiation—Rods, ribbons, or wires placed inside the affected tissue on a short-term or permanent basis
  • Intracavitary radiation—A container of radioactive material is temporarily placed inside a body cavity, such as the uterus, vagina, or windpipe

Rods for Internal Radiation

brachtherapy seeds
Copyright © Nucleus Medical Media, Inc.

How long it will take depends on the type of cancer treated and the method of internal radiation

Anesthesia prevents pain during the procedure. You may be sore when recovering from the procedure depending on where the radioactive material was placed.

You will stay in the hospital until the implant is removed, or in the case of a permanent implant, when the radioactivity has decreased. High-dosage implants are usually removed within a matter of minutes. Low-dosage implants may stay in for a few days. Permanent implants lose their radioactivity within a few days.

Be sure to follow your doctor’s instructions .

You will return to a hospital room while the implant is in place. While the radiation is implanted, you will follow these precautions to prevent transmitting radiation to others:

  • Limited visitation: Many hospitals do not allow children under 18 years old or pregnant women to visit a patient having implant radiation. They may visit after the implant is removed. If visitors are allowed, they will need to sit at least six feet from the bed. Visits will be limited to 10-30 minutes. Staff may place a shield beside the bed to protect visitors and staff from radiation exposure.
  • Limited contact with the staff: The staff will be available to you at all times. They may speak to you from the doorway. They may also come and go very quickly to avoid excessive radiation exposure.

During treatment, your doctor will want to see you at least once a week. You may have routine blood tests to check for the effects of radiation on your blood cells.

After treatment is completed, you will have regular visits to monitor healing and to make sure the treatment affected the disease as planned. Follow-up care will vary for each person. Care may include further testing, medicine, or rehabilitative treatment.

Tell your doctor if you experience side effects. Many side effects can be controlled with medicine or diet. The course of your treatment may be changed if the side effects are too great. Most side effects will gradually go away after treatment.

Call Your Doctor

After arriving home, contact your doctor if any of the following occur:

  • Signs of infection, including fever and chills
  • Diarrhea or loss of appetite
  • Unexplained weight loss
  • Frequent urination, particularly if it is associated with pain or burning sensation
  • New or unusual swelling or lumps
  • Nausea and/or vomiting that you cannot control with the medications you were given
  • Pain that does not go away
  • Unusual changes in skin, including bruises, rashes, discharge, or bleeding
  • Cough, shortness of breath, or chest pain
  • Any other symptom your nurse or doctor told you to look for
  • Any new symptoms

In case of an emergency, call for medical help right away.


National Cancer Institute


Oncolink, Abramson Cancer Center, University of Pennsylvania



Canadian Cancer Society


Cancer Care Ontario



Radiation therapy for cancer. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/factsheet/Therapy/radiation. Updated June 30, 2010. Accessed May 30, 2013.

Cancer treatment information. Oncolink, University of Pennsylvania Cancer Center website. Available at: http://www.oncolink.upenn.edu/treatment/. Accessed May 30, 2013.

Last reviewed May 2013 by Igor Puzanov, MD; Michael Woods, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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