What happens when I have treatment?

This section explains what happens during radiation treatment with either external or internal radiation treatment.


External radiation treatment

The machine you are treated with will depend on the type of cancer you have and what part of your body is affected. For example, superficial therapy machines are better at treating cancers on or near the surface of the skin. Linear accelerators are used to treat cancers deeper in the body. See page 60 for more information about the types of treatment machine. During treatment you will lie still and the machine will move around you so that the radiation can be directed at the tumour from different angles. It is similar to having an X-ray taken. You will not see or feel anything during this treatment.


Maimoatanga iraruke ā-waho

Ka hāngai te mīhini ka whakamahia mōu ki te momo matepukupuku kua pā ki a koe, me te wāhi hoki o tō tinana kua pā taua matepukupuku. Hei tauira atu, he pai ake ngā mīhini haumanu kirimoko mō nga maimoa matepukupuku kei runga i te mata o te kiri. Whakamahia ai ko ngā whakatere ā-rārangi hei maimoa i ngā matepukupuku e noho hōhonu ana ki roto i te tinana. Tirohia a whārangi XX mō te roanga ake o ngā korero e pā ana ki ngā momo mīhini maimoatanga. I te wā o te maimoatanga ka takoto pahoho koe, ka huri te mihīni huri noa i a koe kia hāngai ai te tuku o te iraruke ki te pukupuku mai ngā koki rerekē. He rite ki te mahi a te whakaata roto. Kīhai koe e kite, e rongo rānei i tetahi mea i te wā o te maimoatanga.


Before radiation treatment

You will meet with a radiation oncologist, who will explain why you need this treatment and when it will take place. They will also answer any questions you may have.


The radiation therapist will explain your treatment to you.

Planning your treatment

The first part of treatment planning is called simulation, and is sometimes referred to as marking up or a CT planning session. You will have a CT scan as part of the planning process. You will need to visit the cancer treatment centre at least once before you begin treatment, so that the team can work out the position you will be placed in when having radiation. The doctors and radiation therapists will use the information gathered from your planning appointment to develop an individualised treatment plan. Treatment usually begins two weeks or more after your planning session. In special circumstances people may have planning and treatment on the same day.

It is important to follow any instructions that you are given to prepare for your planning appointment. If you are unsure about the preparation instructions, call the radiation treatment department.


 A CT scanning machine is used to get 3D information to help plan radiation treatment.

CT planning: Part one

During your appointment a radiation therapist will explain what is going to happen and ensure that you have all the required information. This is usually a good time to ask any questions you may have. Once everything has been explained, they may ask you to get changed into a gown or trousers, depending on what area of your body is to be treated.

You will be asked to lie down on the planning couch in a position that is as comfortable as possible. The radiation therapist may use a range of special supports to ensure that you stay in the same position for treatment. Let the therapist know if it is too uncomfortable.

“It’s like an X-ray machine. No worries. You’ve got a comfortable room, music going, then it’s over.” Milly

The radiation therapist will draw some pen marks on your skin (these will wash off). The radiation therapist will leave the room and you will automatically move through the scanner. While the radiation therapist is out of the room, they can see and hear you at all times. If you need them you can call out or wave and they will come straight back in. You will move through the centre of the scanner a few times during the scan. While you are having your scan you will not be able to feel or see anything, but you will hear a whirring noise when the scanner is on. Once the scan is finished the radiation therapist will come back into the room. You will be asked if they can make some small, permanent tattoo dots on your skin to show where the radiation will be given.

Making a mask (shell)

If you are having radiation treatment to your head, neck or throat, you may need to have a mask made. It is hard to keep your head still, so a mask is used to keep you in the right position for treatment. Pen marks will be drawn on the outside of the mask, not on your face. Some people find the thought of wearing a mask throughout treatment quite distressing. Your doctor and radiation therapist can talk to you about your concerns, and are experienced in helping you to manage any feelings of claustrophobia.

“When they made the mask they were really good about talking to me and telling me what they were doing.” Anne-Marie




Here A radiation therapist is showing a patient her plastic mask, which will help her
stay in position as she has treatment. 

CT planning: Part two

For the next part of the planning process you do not need to go to the hospital. The doctor and the radiation therapist will use the information from your scan to plan your treatment.

The radiation treatment team considers many factors, including:

  • the type of radiation to use
  • the size and shape of the area on your body that will be treated
  • your position and the position of the machine
  • how much radiation is to be given in the course of treatment.

Once the plan has been created it is checked by a team of experts to ensure that it is all correct. This part of the process can take up to three weeks. Once your treatment plan has been completed, you will be contacted with the date your treatment starts.


How long is a course of treatment?

External radiation is usually given in a number of treatments. Each treatment is known as a fraction. Fractions are usually given daily from Monday to Friday, with a rest at the weekend to help normal cells to recover. Sometimes treatment is only given on three days each week. It depends on several factors including your general health and the site and type of your cancer.

Curative (radical) radiation treatment

This type of radiation treatment is given with the aim of curing the cancer and is usually used in early stage cancer. This treatment may be given over two to eight weeks. The damage to normal cells is mainly temporary (known as acute side effects). This is what causes the side effects of radiation treatment.

Palliative radiation treatment can be used when your cancer is no longer curable, to reduce and slow the growth of your cancer or to help relieve any symptoms you may be experiencing. For example, palliative radiation treatment can be used to:

  • help control pain
  • reduce coughing
  • help to control bleeding or swelling.

Palliative radiation treatment may be given in one or two sessions or it can be given over a longer period of time. When treatment is given in one or two sessions, it may cause short-term side effects.

Whakamahia ai te maimoatanga iraruke taurima i te wā kāre e taea te whakaora i tō matepukupuku, hei whakaiti, hei whakatōmuri hoki i te tipu o tō matepukupuku, hei āwhina rānei ki te whakahirihiri i ngā tohumate e rongo ana koe

Hei tauira atu, ka āhei te whakamahi i te maimoatanga iraruke taurima hei:

  • āwhina i te mamae
  • whakaiti ake i te maremare
  • āwhina ki te whakahaere i te heke toto, i ngā pupuhitanga rānei.

Ka āhei te hoatu i te maimoatanga iraruke taurima i te wā kotahi, i ngā wā e rua rānei. Ka taea hoki te hoatu mō te wā roa ake rānei. Tērā pea, ka puta he pānga ki te taha mō te wā poto i ngā wā ka hoatuna i te wā kotahi, i ngā wā e rua ranei.

Having treatment

When you arrive each day, you may be asked to change into a hospital gown or trousers. The radiation therapist will take you to the treatment room. You will be asked to lie down on the couch in the same position you were in during your planning appointment. If you have had a mask made, this will be placed on you. The total time you spend in the treatment room will be around 10-20 minutes each treatment.

The radiation therapist will position you for your treatment and then leave the room. You will be able to call or signal them to come back into the room if you need to.

Even if you think the treatment has finished, it is important to stay still until you have been told it is okay to move.


A radiation therapist and radiation oncologist working together to create an individualised treatment plan.

Internal radiation treatment

If you have internal radiation treatment, radioactive seeds or wires (such as caesium, iridium or iodine) will be placed into the body close to your cancer, or into the cancer itself. By doing this, high doses of radiation can be delivered exactly where the cancer is without having to go through healthy tissue. Your doctor might suggest treatment using internal radiation treatment alone or in combination with external radiation treatment and/or chemotherapy.

The types of internal radiation treatment include:

  • brachytherapy – a radioactive source is placed inside the body, either close to or inside your cancer. The type of source depends on the type of cancer
  • radioisotope therapy – a radioactive liquid is injected, or you swallow it, to target the cancer
  • intra-operative radiation – radiation is given during surgery.

These types are explained in more detail below.



There are two types of brachytherapy sources: temporary and permanent. The method used will depend on the type of cancer you have and the area of your body being treated.

Temporary sources

A temporary source is a very small radioactive source (inside an applicator that is not radioactive) that is placed in or near your cancer for a short amount of time. It is removed once each radiation treatment is complete. It is known as a high-dose-rate brachytherapy source.

Placing the applicator may take anything from 20 to 60 minutes and may require a small operation.

You will have your radiation treatment once or twice a day. The total amount of time spent in the treatment room is usually less than an hour.

The staff will leave the room for your treatment, but you will be able to talk to them if you need to. You may hear a slight buzzing noise and some beeps.

Planning your temporary source treatment

Before you start treatment, you will need a planning appointment where you will have a CT scan so that the radiation treatment team can create an individualised plan for you. You may also need an MRI scan. This process can take up to four hours. Your treatment plan is checked before each day of treatment, and may include a CT scan.

After each treatment you will not be radioactive, so you will not need to take any special precautions at home.

Temporary source treatment can be used for a number of cancers, such as:

  • prostate cancer
  • skin cancer
  • gynaecological cancers of the cervix and endometrium
  • oesophagus and bronchus cancer
  • ocular (eye) cancers.


Maimoatanga iraruke ā-roto

Mehemea ka whai koe i te maimoatanga iraruke ā-roto, ka purua he kākano ira rukeruke, he waea kē rānei (pērā ki te caesium, iridium or iodine) ki roto i te tinana kia noho pātata ki tō matepukupuku, ki roto tonu rānei i te matepukupuku. Mā tēnei mahi, ka āhei te tuku i ngā horopeta kaha rawa, hāngai pū ki te wāhi e noho ana te matepukupuku me te karo i ngā kikokiko hauora.

Anei ētahi o ngā momo maimoatanga iraruke ā-roto:

  • brachytherapy – ka purua he pū ira rukeruke ki roto i te tinana, tērā pea ka noho tata ki tō matepukupuku, ki roto kē rānei i tō matepukupuku. Ka hāngai te momo pū ki te momo matepukupuku
  • haumaru radioisotope – ka werohia he wai ira rukeruke, ka horomia rānei e koe, hei whakawhāiti i te matepukupuku.
  • Iraruke intra-operative – ka hoatuna te iraruke i te wā o te hāparapara.

E kore koe e noho iraruke whai muri i ia maimoatanga, nō reira, ehara i te mea me whai whakatūpato motuhake koe ki te kainga.

Permanent sources

A permanent source is a very small radioactive source (smaller than a grain of rice) that is placed, during a short surgical procedure, inside or near your cancer to deliver your radiation treatment. The radiation is released during the following few weeks and gradually reduces until there is no radiation left. This is known as low-dose-rate treatment.

Planning your permanent source treatment

Permanent sources are placed directly into your cancer, so the planning stage is one of the most important parts of your radiation treatment. You will need to go to the hospital to have an ultrasound or a CT scan so that the radiation treatment team can decide where to place the permanent source. You may require an anaesthetic and an overnight stay.

Permanent source treatment can be used for some types of localised cancer, such as prostate cancer.

After each treatment you will be radioactive. You will need to take special precautions at home. Your radiation treatment team will advise you on what you need to do.

E kore koe e noho iraruke whai muri i ia maimoatanga, nō reira, ehara i te mea me whai whakatūpato motuhake koe ki te kainga.


Radioisotope therapy

Radioisotopes are given as liquids in capsules that are swallowed or given by injection into a vein in your arm.

The most common type of radioisotope treatment is radioactive iodine. It is used to treat tumours of the thyroid gland. You may be required to stay in hospital for two or three days in isolation after the treatment is given.

Radioactive iodine does not usually cause side effects, but you might feel very tired for a few weeks after having this treatment.

Please refer to the booklet Understanding Thyroid Cancer by Cancer Council Australia for more information. The booklet is available online at www.cancer.org.au

After being treated with radioactive iodine, you will be radioactive for about one week. You will need to take special precautions at home. Your radiation treatment team will advise you on what you need to do.

Whai muri i te maimoa iodine iraruke, ka noho iraruke koe mō āwhiwhi ki te kotahi wiki. Me whai whakatūpato motuhake koe i te kainga. Mā tō rōpū maimoa iraruke koe e tohutohu ki ngā whakaritenga me whai koe.

Radioisotope treatment for secondary bone cancer

Radioisotope treatment can be given for some cancers that have spread to people’s bones (secondary cancer in the bone). A radioisotope is injected into a vein and is absorbed into the bone, so that the radioactivity damages the cancer cells. The aim of this treatment is to reduce pain and slow the growth of the cancer. You are likely to be given this as an outpatient.

It is important to follow the advice of your doctor after radioisotope treatment.

He mea nui kia whai koe i ngā tohutohu o te rata whai muri i te maimoa radioisotope.


Intra-operative radiation treatment

In intra-operative radiation treatment, low-energy radiation is given in a single dose during surgery for low-risk, early breast cancer. This is a new treatment and has limited availability in New Zealand.


Selective internal radiation therapy

Selective internal radiation therapy (SIRT) uses tiny radioactive beads to treat liver tumours that can’t be removed by surgery. It is a recognised treatment option for hepatocellular carcinoma (HCC), cholangiocarcinoma, and colorectal cancer. SIRT is most often used to treat secondary tumours (metastases) in the liver from cancer that started in the large bowel.

SIRT isn’t funded or available in New Zealand and you would have to travel to have the treatment. Your doctor will be able to advise you if this treatment is an option for you.

Most people have few side effects, but some may have more. These side effects go away in time.


Combining radiation treatment with chemotherapy

Chemotherapy can be given before, during, or after a course of radiation treatment. Chemotherapy and radiotherapy given together is called chemoradiation.

Chemotherapy can make cancer cells more sensitive to radiation treatment and is used to treat several types of cancer, for example rectal cancer and cervical cancer. The combination of treatments may be more effective than having either chemotherapy or radiation treatment alone.