Radiation therapy

Internal radiation therapy

Brachytherapy is the most common type of internal radiation therapy. As with external beam radiation therapy, the main treating specialist for brachytherapy is a radiation oncologist. Procedures for brachytherapy may vary between hospitals. The general process is described in this chapter, but your treatment team can give you more specific information.

How brachytherapy works

In brachytherapy, 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 external beam radiation therapy, but act only over a short distance. It is a way of giving a high dose of radiation to the cancer with a very low dose to surrounding tissues and organs.

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

Planning the treatment

The radiation oncologist will explain the treatment process 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 to determine 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.

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 computerised machines.

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.

If you need to stay in hospital for treatment, take reading material, an iPad or other tablet device, and other activities to keep you occupied while you're alone in the room. 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.

Dose rates

You may be told you are having high-dose-rate, low-dose-rate or pulsed-dose-rate brachytherapy.

High-dose-rate (HDR)

Uses sources that release high doses of radiation in short sessions, each lasting a number of minutes. The sources will be removed at the end of each session.

Low-dose-rate (LDR)

Uses sources that release radiation over days, weeks or months. The sources may be temporary or permanent.

Pulsed-dose-rate (PDR)

Uses sources that release radiation for a few minutes every hour over a number of days. The sources will be removed at the end of treatment.

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

In temporary brachytherapy, the radioactive sources are removed at the end of each treatment session. The sources are often inserted using applicators such as thin plastic tubes (catheters) or cylinders. These applicators may be removed at the end of each session, 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).

Safety precautions

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

In some cases, the treatment will be high-dose-rate brachytherapy (see below) and it will be given for a few minutes at a time during multiple 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.

In other cases, the sources will deliver low-dose-rate or pulseddose-rate brachytherapy over 1–6 days. During this time, you will be an inpatient and will stay alone in a dedicated treatment room within or close to the main hospital ward.

For low-dose-rate or pulsed-dose-rate brachytherapy, hospital staff will only come into the room for short periods of time, and visitors may be restricted – children under 18 and pregnant women are usually not allowed to enter the room. You can use an intercom to talk with staff and visitors outside the room.

Once the sources are removed, you are not radioactive and there is no risk to other people.

Permanent brachytherapy

In permanent brachytherapy, radioactive seeds about the size of an uncooked grain of rice are put inside special needles and implanted into the body. The needles are removed, and the seeds are left in place to gradually decay. As the seeds decay, they release small amounts of radiation over weeks or months. They will eventually stop releasing radiation, but they will not be removed. This is a low-dose-rate technique and it is often used to treat small prostate cancers.

Safety precautions

If you have permanent brachytherapy, you will be radioactive for a short time after the seeds are inserted. The radiation is usually not harmful to people around you, so it is generally 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 usually 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 three 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 particular cancers, you may be referred to a nuclear medicine specialist for other types of internal radiation therapy.

Radionuclide therapy

Also known as radioisotope therapy, this therapy involves radioactive material being taken by mouth as a capsule or liquid or given by injection. The material spreads through the body, but particularly targets cancer cells.

Different radionuclides are used to treat different cancers. The most common radionuclide therapy is radioactive iodine, which is taken as a capsule and used for thyroid cancer. Understanding Thyroid Cancer has more information about this treatment – call 13 11 20 for more information. Other radionuclide therapies are used for neuroendocrine tumours (NETs) of the pancreas, bowel and lung; some advanced prostate cancers; cancer that has spread to the bone; and lymphoma. Talk to your treatment team or call 13 11 20 for more information.


Also known radioembolisation, SIRT stands for selective internal radiation therapy. This method delivers high doses of radiation to cancers in the liver. It uses tiny pellets called microspheres, which contain a radioactive substance. The pellets are injected into a thin tube called a catheter, which is inserted into the main artery (hepatic artery) that supplies blood to the liver. Radiation from the microspheres damages the blood supply of the cancers. This means the cancers can't get the nutrients they need and they shrink. Read more about SIRT in Understanding Cancer in the Liver.

Key points

  • Brachytherapy uses radiation to directly target and destroy cancer cells.
  • The radiation sources may include "seeds", needles or wires that will be put into your body inside or near the cancer.
  • You may have high-dose-rate, low-dose-rate or pulsed-doserate brachytherapy.
  • How long the radiation sources are left in place varies and depends on the dose required. Temporary sources can remain in place for minutes, hours or days. Permanent sources will not be removed.
  • For some types of temporary brachytherapy, you may need to stay in hospital in an isolated room, and visitors may be restricted.
  • No radiation will be left in your body after a temporary implant is removed. If you have a permanent implant, the risk of exposing other people to radiation is very low, but you may need to avoid contact with young children and pregnant women for a short time. Your treatment team will advise you of any precautions you need to take.
  • Radionuclide therapy is taken as a capsule or liquid, or given as an injection. The most common therapy of this kind is radioactive iodine, which is used to treat thyroid cancer.
  • SIRT stands for selective internal radiation therapy. Also known as radioembolisation, this method uses tiny beads to deliver high-dose radiation therapy, usually to the liver.

Expert content reviewers:

Dr Tiffany Daly, Radiation Oncologist, Radiation Oncology Princess Alexandra Raymond Terrace (ROPART), South Brisbane, QLD; Elly Keating, Acting Principal Radiation Therapist, Northern Territory Radiation Oncology, Alan Walker Cancer Care Centre, NT; Julie O'Rourke, Clinical Nurse Consultant, Radiation Oncology, Canberra Hospital, ACT; Ching Tsao, 13 11 20 Consultant, Cancer Council NSW; A/Prof Sandra Turner, Clinical Lead, Targeting Cancer Campaign, Faculty of Radiation Oncology, Royal Australian and New Zealand College of Radiologists (RANZCR), NSW; Dr David Waterhouse, Acting Principal Radiation Oncology Medical Physicist, Sir Charles Gairdner Hospital, WA; David Wells, Consumer.

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