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Internal radiotherapy

For this treatment, a small metal implant that gives off radiation is put in or near to the cancer. See when and how you might have internal radiotherapy.

What it is

Internal radiotherapy is also called brachytherapy. This is when the radiation source is inside your body. The radiation source is a metal object that gives off the radiation. It may be positioned within the cancer or very near to it. This way, the tumour gets a high dose of radiation, without damaging the surrounding tissue. 

When is it used

Internal radiotherapy is not used as often as external radiotherapy for nasopharyngeal cancer. You are most likely to have internal radiotherapy:

  • if your cancer has come back after earlier treatment with external radiotherapy
  • as a booster dose at the end of a course of external radiotherapy

Why it works

The benefits of using internal radiotherapy for nasopharyngeal cancers are:

  • nearby structures such as the brain, spinal cord and eyes don’t receive high doses of radiation
  • you can give high doses to tumours, that can’t be treated any more with external radiation (salvage brachytherapy)


You may have radioactive implants to treat your cancer. There are 2 ways of doing this:

  • radioactive sources are placed alongside the tumour (intracavitary radiotherapy)
  • radioactive implants are put into the cancer and surrounding tissues (interstitial radiotherapy and permanent implants)

Intracavitary radiotherapy

Intracavitary radiotherapy delivers a high dose of radiation as close to the cancer as possible. Intracavitary means an implant that gives off radiation is placed in a cavity near the tumour.

What happens

To reach a tumour in your nasopharynx, you have a thin tube (catheter) put into your mouth or up your nose. Your doctor uses an anaesthetic spray to numb your mouth, throat or nose. This makes it more comfortable when the catheter goes in.

The catheter is then connected to a brachytherapy machine, which contains a radioactive metal ball. The doctor leaves the room.

The metal ball leaves the machine and travels into the catheter. It then releases a dose of radiation. This lasts for a few minutes. Afterwards the doctor comes back in and detaches the catheter from the machine.

You usually have up to 6 treatments with at least 2 days rest in between treatments. After each treatment you can go home. If you have a long way to travel, your doctor might suggest you stay in during your treatment period.

Interstitial radiotherapy

You have interstitial radiotherapy under a general anaesthetic. The doctor places some thin hollow tubes directly into your tumour. You may have an x-ray to make sure they are in the correct position.

The implants can stay in place anywhere from a few minutes up to a few days. They might stay in for 2 days if you have them as a booster treatment after external radiotherapy. Or they might stay in for between 3 and 5 days if they are your only treatment.

What happens

For the treatment, the radiographers connect the tubes to a brachytherapy machine. This machine contains a radioactive metal ball. The ball travels out of the machine and enters the tubes. It releases high doses of radiotherapy directly to your tumour.

You can have up to two treatments a day. They do not last long but you have to be alone while you have the treatment. The radiographers watch you from outside the room during the treatment, on a closed circuit television screen.

You then have another general anaesthetic and have the tubes taken out. You are likely to feel sore for up to 2 or 3 weeks after you have had the implant removed.

Having implants in can be uncomfortable. They can make eating and talking difficult. You might need a soft or liquid diet while the implants are in place.

Permanent implants

Sometimes permanent radioactive implants are used to treat nasopharyngeal cancer. They are small radioactive gold pellets the size and shape of a grain of rice. They are put into the cancer and surrounding tissue and stay there forever.

Permanent implants contain a small level of radiation that eventually loses its strength over a few weeks. The radiation can only travel a short distance. So the tumour gets nearly all the radiation dose. The radioation has very little effect on the surrounding tissues and organs. It is not a risk to you or anyone around you.

What happens

You have this treatment at a hospital. The doctor places the pellets in the tumour while you are under general anaesthetic.

You stay on the ward in an isolated room for the first night following the procedure. This is so other people can't be exposed to the radiation, which is at its strongest. After this you are free to go home.

Your doctor usually calls you back after 6 weeks to have a CT scan. This is to check the pellets are still in place and haven't moved.

Your doctor also gives you a card to carry for a while. You show this to your dentist or any hospital staff if you have another treatment. This is to let them know that you have these pellets in you. Let your next of kin know about the card and procedure in case you end up in hospital and are unable to give the information yourself.

Last reviewed: 
26 Aug 2014
  • Radiotherapy in Practice - Brachytherapy
    P Hoskin and C Coyle
    Oxford University Press, 2011

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