Internal radiotherapy is used only for certain types of cancer, such as prostate cancer, some gynaecological cancers, thyroid cancer, cancer in the liver, and some head and neck cancers. It delivers a high dose of radiation directly to the tumour, limiting the dose to surrounding tissues. Internal radiotherapy is given in different ways:
The radioactive sources are placed inside the body close to or inside the tumour. These sources are called implants. The type of implant used depends on the type of cancer and may include seeds, needles, wires or capsules.
Radioactive therapy is taken in capsule or liquid form, or given by injection. Radionuclide therapy is also called radioisotope therapy.
Tiny pellets containing a radioactive substance are injected into an artery to treat cancer in the liver.
Your doctor may recommend internal radiotherapy alone or in combination with external radiotherapy. You may have internal radiotherapy as an inpatient or outpatient, depending on the type of treatment you have.
Planning and treatment procedures for internal radiotherapy may vary between hospitals. The general process is described in this section. Your treatment team can give you more specific information.
Planning for internal radiotherapy is different from planning for external treatment and will depend on whether you have brachytherapy (see below), radionuclide therapy or selective internal radiation therapy.
The radiation oncologist will explain the treatment process and tell you whether you will have treatment as an inpatient or outpatient. You will have tests and scans to help your treatment team decide where to place the implants and to determine the correct dose to deliver to the tumour. These tests may include an ultrasound, MRI scan and CT scan.
The oncologist will explain possible side effects and give you information about safety precautions you might need to take after treatment, as you may be radioactive for a short time when you return home.
You will usually see other specialists who are part of your treatment team. For example, you may see an anaesthetist if you will need anaesthetic during radiotherapy.
If you have radiotherapy as an inpatient, take reading material 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.
The way the implants are placed inside the body varies. Generally, one or more applicators will be inserted into or near the tumour for the implants to pass through and into the body. Applicators come in different shapes and sizes and are not radioactive.
The process of inserting the applicators and placing the implants inside them is often done in a dedicated room called a brachytherapy suite. In some hospitals, it is carried out in an operating theatre, which means you will need to stay in hospital for the day or overnight.
While you are under either a local or general anaesthetic, the doctor will use an x-ray machine or ultrasound scanner to guide the applicators into position. The placement of the applicators will depend on the type of cancer. For example, for prostate cancer, they will be inserted into the prostate gland; for gynaecological cancers, they will be placed into the vagina or uterus.
Once the applicators are in place, the implants will be put into or near the tumour through the applicators, either manually by the doctor or through a special machine.
The applicators will be removed from your body when treatment is finished. The implants may also be removed or they may remain in place permanently without causing any harm or discomfort (see below).
Implants can be temporary or permanent depending on the dose of radiation required.
Some implants remain in place for 1–6 days before being taken out along with the applicator.
You will stay in hospital during this time, usually in an isolated room or a room away from the main ward.
In other cases, the implants deliver radiation over a few minutes during multiple sessions as an outpatient. The applicator may be left inside you between sessions, or it may be inserted and removed each time.
Seeds or pellets about the size of a grain of rice are put inside special needles and implanted into the body. They release small amounts of radiation over weeks or months. The implants are left in place permanently to gradually decay, and the needles are removed.
Brachytherapy will cause you to be radioactive for a short time, depending on whether the implants are temporary or permanent.
While the implants are in place, some radiation may pass outside your body. For this reason, hospitals take safety precautions to avoid exposing staff and your visitors to radiation. Staff will explain any restrictions before you start treatment.
Once the implants are removed, you are not radioactive and there is no risk to other people.
These will cause you to be radioactive for a short time after they are inserted. The radiation level drops over a period of weeks or months until no radiation is detected by tests. The radiation is not usually harmful to people around you, so it is generally safe to go home. Your treatment team will advise you of any precautions to take.
You should not have any severe pain or feel ill during brachytherapy. If the implants 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 for some time. In some cases, you may have to limit physical and sexual activity for a period of time. Your doctor will advise you about this.
Radionuclide or radioisotope therapy is when radioactive material is taken by mouth as a capsule or liquid or given by injection to target 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.
Radionuclide therapy may require a short stay in hospital. During this time, you will be radioactive and in a room on your own. The radioactive material that is taken up by the cancer cells decays and becomes less radioactive each day.
Any radioactive material not taken up by the cancer cells will be passed out of your body, mostly in urine, but also in sweat, saliva and faeces. Your treatment team will advise you to drink plenty of water and pass urine regularly to help reduce the amount of radioactive material in your body.
The level of radiation will be measured regularly during your hospital stay. You will be able to go home once the level is considered low enough for you to be around other people.
For more information see iodine treatment for thyroid cancer.
You may need to take some safety precautions for a short while after you get home, such as limiting close contact with other people and being careful to avoid exposing others to bodily fluids, such as urine, faeces, saliva and sweat. Your radiation oncologist, medical physicist or nurse will discuss these precautions with you.
SIRT or radioembolisation is a way of delivering high doses of internal radiotherapy to treat tumours in the liver. The treatment 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 tumours. This means they are unable to get the nutrients they need and they shrink. Each pellet gives out radiation to a small area. Normal liver cells should only receive a small amount of radiation and there should be few side effects.
To plan for SIRT, you may need to stay in hospital for a night. Once the pellets are in place, they deliver radiotherapy continuously for 10–14 days. After treatment has finished, the pellets will remain in your body permanently without causing any harm or discomfort.
See more on SIRT.