Internal radiotherapy

Internal radiotherapy is when you have radiotherapy from inside your body. It is also called brachytherapy.

A small radioactive source goes into your vagina through hollow tubes (applicators). This gives a high dose of radiation to the top of the vagina, but only a little to surrounding tissues. This means there are fewer side effects to other organs in the pelvis.

Most people have both brachytherapy and external radiotherapy for womb cancer. Some people with very early cancers may have brachytherapy on its own after surgery.

You usually have between 2 to 4 treatments. The number of treatments you need depends on whether you’ve already had external radiotherapy.

What happens


You lie down on the CT scanner. Your radiographer or doctor examines you to check what size applicator they can use for the treatment. The applicator is a plastic tube which comes in different sizes.

They cover the top of the applicator with anaesthetic gel and gently put it into your vagina. This is not painful but can be a little uncomfortable. The applicator is held in place with a clamp that attaches to the bed.

You then have a CT scan of your pelvis with the applicator in place. This helps your doctor to plan your treatment. It can take about half an hour.

Photo of a CT scanner

After the scan the applicator is removed and you can go home. Once the treatment has been planned you come back for treatment.

Before treatment

You lie down in the bracytherapy room on the bed and the radiographer gently puts the same applicator in your vagina. This is held in place with a clamp that attaches to the bed.

Having treatment

Your radiographer connects the applicator to the brachytherapy machine. They then leave the room and switch on the machine. They can still see you on a CCTV screen and can talk to you through an intercom.

The machine contains a small radioactive pellet, which leaves the machine and enters the applicator. The treatment itself is painless and takes about 5 to 10 minutes.

The machine automatically removes the radioactive source from the applicator when treatment is finished.

The treatment is the same every time. You do not normally need a vaginal examination or CT scan at your other treatment sessions.

After treatment

Your radiographer removes the applicator. You can then go home. You are not radioactive after treatment, so it is safe for you to be with other people including children.

Side effects

Radiotherapy can cause different side effects including:

  • diarrhoea
  • bladder problems such as a burning feeling when you pass urine or passing urine more often
  • a sore vagina, and vaginal discharge or bleeding

In the long term, your vagina may become shorter, narrower and less stretchy. To try to prevent this, your radiographer or nurse will give you vaginal dilators to use regularly after your radiotherapy treatment.

Last reviewed: 
05 Feb 2020
Next review due: 
10 Feb 2023
  • Principles and practice of oncology (11th edition)
    VT De Vita, TS Lawrence and SA Rosenberg
    Lippincott, Williams and Wilkins, 2018

  • ESMO-ESGO-ESTRO Consensus Conference on Endometrial Cancer: diagnosis, treatment and follow-up

    N Columbo and others (2016) 

    Annals of Oncology 27: 16–41