Internal radiotherapy is only used for certain types of cancer, such as prostate cancer, some types of gynaecological cancer, thyroid cancer and cancer affecting the liver. It delivers a high dose of radiation close to the tumour, directly affecting the cancer while limiting the dose to the surrounding tissues. This is given in different ways:
- Brachytherapy – The radioactive sources are placed in the body, close to, or inside the cancer. This is called an implant. The type of implant used depends on the type of cancer you have, and may include seeds, needles, wires, capsules or other devices.
- Radioisotope therapy – This uses radioactive liquid that is taken by mouth as a capsule or given by injection.Your doctor may recommend internal radiotherapy alone or in combination with external radiotherapy.
How is the implant placed in the body?
An applicator may be used to hold the implant against the tumour. Applicators come in different shapes and sizes, and can contain different radioactive materials. The applicator itself isn’t radioactive.
You might need to stay in hospital or have day surgery to have the applicator inserted. The doctor will use an x-ray or ultrasound scanner to guide it into position. You can have pain relief to make you more comfortable during this procedure. Afterwards, a machine is used to pass the radioactive sources into the applicator.
How long will it be in place?
There are many different types of implants – some deliver low doses of radiation; others deliver high doses. They can be temporary or permanent.
- Temporary implants – These may be in place for 1–6 days before being taken out. You will stay in hospital during this time. In other cases, the implant delivers radiation over a few minutes during several sessions.
- Permanent implants – Seeds or pellets about the size of a grain of rice are left in place permanently to gradually decay. Over a period of weeks or months the radiation level drops, but the seeds remain in place with no lasting effect.
Will the implant be painful?
You should not have any severe pain or feel ill during implant therapy. If your implant is being held in place by an applicator, it may be uncomfortable, but your doctor can prescribe medicine to relax you and relieve any pain.
Once the applicator is removed, you may be sore or sensitive in the treated area for some time. In some cases, your doctor might suggest that you limit physical and sexual activity for a while.
Will I be radioactive?
While the radioactive applicator is in place, some radiation may pass outside your body. For this reason, hospitals take several safety precautions to avoid unnecessary exposure to staff or your family and friends while the implant is in place. The hospital staff will explain any restrictions to you before you start treatment. These may include the following requirements:
- You may be alone, or in a room away from the main ward.
- Hospital staff will only stay in the room for short periods of time, and visitors may be restricted while the implant is in place – children under 18 or pregnant women are not usually allowed to enter the room
- You can use an intercom to talk with hospital staff and visitors.
- Once the temporary implant is removed, you are not radioactive and there is no risk to others.
If you have a permanent implant, you will be radioactive for a short while and may need to stay in an isolated room for a few days. You may have temporary restrictions placed on your activities such as being around small children or pregnant women.
- Take in reading material and other items to keep you occupied while you’re alone in the room. You may also be able to watch television or listen to the radio.
- Let the staff know if you feel anxious in confined spaces (claustrophobic), as they may be able to give you medication to ease this feeling.
This uses radioactive material that is taken by mouth as a capsule or given by injection.
Different radioisotopes are used to treat different cancers. The most common radioisotope treatment is radioactive iodine, which is used to treat thyroid cancer. Other types may be used to treat liver cancer and non-Hodgkin lymphoma.
Radioisotope therapy requires a short hospital stay. During this time you will be in an isolation room while you are temporarily radioactive. The radioactive iodine taken up by the thyroid cells becomes less radioactive each day. Any iodine not taken up by the thyroid cells is passed out of the body in urine, sweat or faeces.
The amount of radiation that is in your body is measured regularly during your hospital stay. Once the radiation level in your body reaches a safe level, you will be able to go home.
There may be some special precautions or care that you need to take for a short while after you are home. Talk to your radiation oncologist or nurse about what to bring to hospital, and about any special care that may be required after discharge.
Treating secondary bone cancer
Radioisotopes can be used to treat secondary bone cancer. The radioisotope is injected into a vein and circulates to the area of the cancer in the bone. This is a simple procedure and a hospital stay is usually not needed.
Selective internal radiotherapy treatment (SIRT)
SIRT is a way of delivering high doses of internal radiotherapy to treat tumours in the liver.
SIRT 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 that supplies blood to the liver (hepatic artery).
Radiation from the microspheres damages the tumours’ blood supply. The tumours can’t get the nutrients they need and shrink. This process is sometimes called radioembolisation.
Each pellet gives out radiation to a small area. This means normal liver cells should only receive a small amount of radiation, which should reduce the side effects you experience.
The pellets deliver radiotherapy continuously for 10–14 days. After they have stopped working, the pellets remain in the body permanently, but they don’t cause any problems.