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Radiation therapy


Page last updated: April 2024

The information on this webpage was adapted from Understanding Radiation Therapy - A guide for people with cancer, their families and friends (2024 edition). This webpage was last updated in April 2024.

Expert content reviewers:

This information was developed with help from a range of health professionals and people affected by cancer who have had radiation therapy:

  • A/Prof Susan Carroll, Senior Staff Specialist, Radiation Oncology, Royal North Shore Hospital, and The University of Sydney, NSW
  • Katie Benton, Advanced Dietitian Oncology, Sunshine Coast Hospital and Health Service, QLD
  • Adrian Gibbs, Director of Physics, Radiation Oncology, Princess Alexandra Hospital Raymond Terrace, QLD
  • Sinead Hanley, Consumer
  • Dr Annie Ho, Radiation Oncologist, GenesisCare, Macquarie University Hospital and St Vincent’s Hospital, NSW
  • Angelo Katsilis, Clinical Manager Radiation Therapist, Department of Radiation Oncology, Royal Adelaide Hospital, SA
  • Candice Kwet-On, 13 11 20 Consultant, Cancer Council Victoria
  • Jasmine Nguyen, Radiation Therapist, GenesisCare Hollywood, WA
  • Graham Rees, Consumer
  • Nicole Shackleton, Radiation Therapist, GenesisCare Murdoch, WA
  • Dr Tom Shakespeare, Director, Cancer Services, Mid North Coast Local Health District, NSW
  • Gabrielle Vigar, Nurse Lead, Cancer Program, Royal Adelaide Hospital and Queen Elizabeth Hospital, SA

Brachytherapy is the most common type of internal radiation therapy. It is used to treat some types of cancer, including breast, cervical, prostate, uterine and vaginal. As with external beam radiation therapy (EBRT), the main treating specialist for brachytherapy is a radiation oncologist. 

How brachytherapy works

How you have brachytherapy may vary between hospitals. Generally, sealed radioactive sources are placed inside the body, close to or inside the cancer.

The sources produce gamma rays, which have the same effect on cancer as the x-rays used in EBRT, but act over a short distance only. It is a way of giving a high dose of radiation to the cancer with only a very low dose reaching surrounding tissues and organs.

The type of brachytherapy used depends on the type of cancer. It may include seeds (pellets), needles, wires, pellets or small mobile sources that move from a machine into the body through applicators (thin plastic tubes). Brachytherapy may be used alone or with EBRT.

Planning brachytherapy

The radiation oncologist will explain what treatment will involve and tell you whether you can have treatment during a day visit (outpatient) or will need a short stay in hospital (inpatient).

You will have tests and scans to help your team decide where to place the radioactive sources and work out the correct dose to deliver to the cancer. These tests may include an ultrasound, CT scan and/or MRI scan.

The radiation oncologist will explain possible side effects and discuss any safety precautions. For some cancers, imaging tests, planning and treatment may all occur in the same session.

If you need to stay in hospital for treatment, take reading material and other activities to pass the time. You may also be able to watch television or listen to music. Check with your doctor what you can take into the room, as there may be restrictions.

What to expect at treatment sessions

Depending on the type of brachytherapy you are having, you may need to have a local anaesthetic to numb the area being treated, or a general anaesthetic so you will be unconscious for the treatment.

The radiation sources will be positioned in your body, sometimes with the help of imaging scans (such as x-ray, ultrasound and CT) and computers. You should not have any severe pain or feel ill during a course of brachytherapy.

If the radioactive sources are being held in place by an applicator, you may feel some discomfort, but your doctor can prescribe medicine to help you relax and relieve any pain. Once the applicator is removed, you may be sore or sensitive in the treatment area.

After the treatment, you may have to limit physical and sexual activity and take some safety precautions for a period of time – your treatment team will advise you.


Dose rates

You may be told you are having high-dose-rate or low-dose-rate brachytherapy. Pulsed-dose-rate brachytherapy is not used often.

  • High-dose-rate (HDR) uses a single source that releases high doses of radiation in short sessions, each lasting a number of minutes. The source is removed at the end of each session.
  • Low-dose-rate (LDR) uses multiple sources or seeds that release radiation over days, weeks or months. The sources may be temporary or permanent.
  • Pulsed-dose-rate (PDR) uses a single source that releases radiation for a few minutes every hour over a number of days. The source is removed at the end of treatment. 

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Types of brachytherapy

Depending on the type of cancer and your radiation oncologist’s recommendation, the radioactive sources may be placed in your body for a limited time or permanently. 

Temporary brachytherapy

With temporary brachytherapy, you may have one or more treatment sessions to deliver the full dose of radiation. The radioactive source can be inserted using applicators such as thin plastic tubes (catheters) or cylinders. It can also be delivered using small discs call plaques.

The source is removed at the end of each treatment session. The applicator may be removed at the same time or left in place until after the final session.

Temporary brachytherapy is mostly used for prostate cancers and gynaecological cancers (such as cervical and vaginal cancers). Radioactive plaques are used to treat some eye cancers.

Safety precautions for temporary brachytherapy 

While the radioactive source is in place, some radiation may pass outside your body. For this reason, hospitals take certain safety precautions to avoid exposing staff and visitors to radiation. Staff will explain any restrictions before you start brachytherapy treatment.

If you have temporary brachytherapy, once the source is removed, you are not radioactive and there is no risk to other people. You won’t have to take any further precautions.

  • High-dose-rate brachytherapy – this will be given for a few minutes at a time during several sessions. The radiation therapists will leave the room briefly during the treatment, but will be able to see and talk to you from another room. You may be able to have this treatment as an outpatient.
  • Low-dose-rate or pulsed-dose-rate brachytherapy – the radioactive sources will deliver radiation over 1–6 days. For these types of brachytherapy, you will stay in hospital for a few days and will be in a dedicated treatment room on your own. This room is close to the main hospital ward and you can use an intercom to talk with staff and visitors outside the room. If you have concerns about being alone, talk to the treatment team.

For low-dose-rate or pulsed-dose-rate brachytherapy, while the radiation source is in place precautions may include:

  • hospital staff only coming into the room for short periods of time
  • limiting visitors during treatment
  • visitors sitting away from you
  • avoiding contact with children under 16 and pregnant women.

Permanent brachytherapy

In permanent low-dose-rate brachytherapy, radioactive seeds about the size of a grain of rice are put inside special needles and implanted into the body while you are under general anaesthetic. The needles are removed, and the seeds are left in place to gradually decay.

As the seeds decay, they slowly release small amounts of radiation over weeks or months. They will eventually stop releasing radiation, but they will not be removed. Low-dose-rate brachytherapy is often used to treat early-stage prostate cancers.

Safety precautions for permanent brachytherapy

If you have permanent brachytherapy, you will be radioactive for a short time after the seeds are inserted. The radiation is usually not strong enough to be harmful to people around you, so it is safe to go home.

However, you may need to avoid close contact with young children and pregnant women for a short time – your treatment team will advise you of any precautions to take.

You will normally be able to return to your usual activities a day or two after the seeds are inserted.


“For the first few weeks after the seeds were implanted, I thought this is a doddle. Then suddenly, I started getting this really urgent need to urinate. That gave me a few weeks of disturbed sleep, but the urgency gradually eased off and I thought this is pretty good. Now after 3 years, there’s no sign of the cancer and I’ve had no long‑term side effects.” Derek

Other types of internal radiation therapy 

For some cancers, you may be referred to a nuclear medicine specialist to have another type of internal radiation therapy.

Radionuclide therapy

Also known as radioisotope therapy, this involves radioactive material being taken by mouth as a capsule or liquid, or given by injection. The material spreads throughout the body, but particularly targets cancer cells. It delivers high doses of radiation to kill cancer cells with minimal damage to normal tissues.

Different radionuclides are used to treat different cancers. The most common radionuclide therapy is radioactive iodine, which is taken as a capsule and used to treat certain types of thyroid cancer.

Other radionuclide therapies include:

  • peptide receptor radionuclide therapy (PRRT), used to treat neuroendocrine tumours (NETs) of the bowel, pancreas and lung.
  • lutetium prostate specific membrane antigen (PSMA) therapy, used to treat some advanced prostate cancers
  • I-MIBG therapy, used to treat some types of NETs or neuroblastoma
  • bone-seeking radioactive liquid, used to target cancer that has spread to the bone
  • radioactive antibodies, used to treat lymphoma

Radionuclide therapies may be available only in certain specialised treatment centres in each state and some may be available only on clinical trials or at a considerable out-of-pocket cost. Talk to your doctors for more information.

Selective internal radiation therapy (SIRT)

Also known as radioembolisation, SIRT stands for selective internal radiation therapy. This method uses tiny radioactive beads to deliver high doses of radiation to the liver.

The beads are injected into a thin tube called a catheter, which is inserted into the main artery that supplies blood to the liver.

Radiation from the beads damages the cancer cells and their blood supply. This means the cancer can’t get the nutrients it needs and it shrinks. 


Understanding Radiation Therapy

Download our Understanding Radiation Therapy booklet to learn more.

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