What is internal radiotherapy?

Internal radiotherapy is treatment with a radioactive material that is put inside the body to treat cancer. There are different types of internal radiotherapy. We have information about the following types:

  • brachytherapy
  • radioisotope or radionuclide therapy
  • selective internal radiation therapy (SIRT).

Brachytherapy

Brachytherapy uses radioactive implants such as seeds, pellets, wires or plates that are put near or inside the tumour. The radioactivity only affects tissue that is very close to the implant. This means the tumour is treated, but healthy areas around it get much less radiotherapy. Areas of the body that are further away are not affected at all.

The implants are left in place to give the correct dose of treatment. Depending on the type of brachytherapy, this may take a few minutes or a few days. Some types of implants are designed to be left in the body permanently.

Your team will explain your treatment plan. This may also involve external beam radiotherapy or other treatments such as chemotherapyhormonal therapy or targeted therapy.

Brachytherapy is mainly used to treat cancers in the prostatecervix and womb. It is sometimes used to treat other cancers, such as cancer of the vaginavulvaoesophagus (gullet)lungrectum and eye.

Brachytherapy can be given in different ways for each cancer type.

Radioisotope therapy

Radioisotope therapy uses radioactive liquid (known as radioisotopes or radionuclides) to destroy cancer cells.

The liquid can be given:

  • by mouth as a drink or capsules
  • as an injection into a vein.

Cancer cells take in the radioisotope more than normal cells do. This means they get a higher dose of radioactivity. This eventually destroys the cancer cells.

Your team will tell you how you will have your treatment and any possible side effects.

Types of radioisotope therapy

  • Iodine-131

    This is the most common type of radioisotope therapy. It is mainly used to treat some types of thyroid cancer. It may also be used to treat other rarer neuroendocrine tumours. You usually have it as capsules or a drink. But it can also be given as an injection into a vein in the arm. You may have to stay in hospital to have this treatment.

  • Strontium-89 and Samarium-153

    These radioisotopes can be used to treat some types of cancer that have spread to the bones (metastatic bone cancer). This treatment can help reduce bone pain and improve quality of life. You can usually go home soon after having this treatment.

  • Radium-223

    This radioisotope is sometimes used to treat prostate cancer that has spread to the bones. It may be used if hormone therapy alone is no longer controlling the cancer. You can usually go home soon after having this treatment. 

Selective internal radiation therapy (SIRT)

Selective internal radiation therapy (SIRT) is a type of internal radiotherapy that uses radioactive beads. It is used to treat some types of liver cancer. For example, it may be used to treat cancer that spreads to the liver from the bowel.

SIRT is not widely available and is not always funded by the NHS. You may have it as part of a research trial. If your cancer team think it is suitable for you, you may have to travel to a specialist hospital to have it.

SIRT is also called radioembolisation.

We have more information about SIRT to treat liver tumours.

Is internal radiotherapy safe?

Your treatment is planned to give you the amount of radiation needed to treat the cancer safely and effectively. Your team are also careful to protect people around you from radiation. Safety measures may be slightly different in different hospitals. Your team will explain what to expect.

Radiation safety during brachytherapy

During your treatment in hospital you may be looked after in a single treatment room. This depends on the type of brachytherapy you have. You may need to be alone in the room at times. Tell your team if you are worried about this so they can help.

As soon as the implants are removed from your body, there is no risk to people around you. You are not radioactive.

For some types of brachytherapy, the implants are not removed (for example, permanent seed implants or SIRT – see below). The radiation from each implant is absorbed by the area of the body closest to it. It is safe for you to be around most other people. As a precaution, you may have to avoid close contact with children or pregnant women for a time. Your team will explain this and any other safety measures to you. They will give you information about your treatment to carry with you.

Radiation safety during radioisotope therapy

After radioisotope therapy, your body fluids are slightly radioactive for a time. Your team will give you instructions about using the toilet and cleaning up any spilled body fluids safely. You may be advised to avoid close contact with children or pregnant women for a time.

If your treatment involves a stay in hospital, you may be cared for in a single treatment room. You may be asked to stay in your room at all times. Tell your team if you are worried about this so they can help.

Your team will tell you any other safety measures you need to follow.

Radiation safety during SIRT

Almost all the radiation from each SIRT bead is absorbed by the area of the body closest to it. But your body fluids will be slightly radioactive for a time. It is safe for you to be around most other people. As a precaution, you may have to avoid close contact with children or pregnant women for a time.

Your team will explain this and any other safety measures you need to know about or follow at home.

Your team will also give you information to carry with details of your treatment.