External radiotherapy is normally given as a series of short, daily treatments in the radiotherapy department, using equipment similar to a large x-ray machine.

The treatments are usually given from Monday to Friday, with a rest at the weekend. Each treatment is called a fraction. Giving the treatment in fractions ensures that less damage is done to normal cells than to cancer cells. The damage to normal cells is mainly temporary, but is the reason why radiotherapy has some side effects.

The number of treatments you have depends on several factors, including:

• your general health
• the type of cancer being treated and where it is in the body
• whether or not you have had, or are going to have, surgery, chemotherapy or hormonal therapy as part of your treatment.

For these reasons, treatment is individually planned for each patient, and even people with the same type of cancer may have different types of radiotherapy treatment.

External radiotherapy does not make you radioactive, and it is perfectly safe for you to be with other people, including children, throughout your treatment.

A course of curative (radical) treatment may be given every weekday for two to seven weeks.

Instead of having one treatment a day or having a rest at the weekend, some people will have different treatment plans. They may have more than one treatment daily, or treatment every day for two weeks. Sometimes treatment may only be given on three days each week (for example, Mondays, Wednesdays and Fridays).

Palliative treatment (for symptom control) may involve only one or two sessions of treatment, or up to ten sessions.

There are several different types of radiotherapy machines that work in different ways. Radiotherapy treatment for most cancers, apart from skin cancers, is given by machines called linear accelerators (LinAcs).

The type of radiotherapy machine used will be chosen by your specialist and physicist to give you the most appropriate treatment. Some machines are quicker than others and may give treatment in a very short time, such as a few seconds. Usually, radiotherapy treatment (including the time taken to position you) takes 10–15 minutes.

The radiotherapy machine does not normally touch you, although for some types of cancer it may press against your skin. If you have a specific type of radiotherapy known as electron treatment, a small applicator may be used, which touches a small area of skin.

The treatment itself is painless, although it may gradually cause some uncomfortable side effects.

Radiotherapy affects people in different ways; some find that they can carry on working, only needing time off for their treatment, while others find it too tiring and prefer to stay at home. If you have a family to look after, you may find that you need extra help.

Don't be afraid to ask for help, whether it's from your employer, family and friends, social services, or the staff in the radiotherapy department. As your treatment progresses, you’ll have a better idea of how it makes you feel, so you can make any necessary changes to your daily life.

If possible, the radiotherapy staff will try to give you an appointment for the same time each day. This allows you to get into a regular routine.

If you have to do a lot of travelling each day to get to your appointment you may feel very tired, particularly if you are feeling some side effects from your treatment.

If the treatment makes you feel tired, you could ask a family member or friend to drive you to the hospital.

If you rely on your own or public transport you can sometimes arrange a radiotherapy appointment which suits you. However, due to the large numbers of people having radiotherapy, it's not always possible to get an appointment exactly when you want it.

Some hospitals provide transport and, if necessary, this can be arranged for you. The hospital’s transport department will assess your needs and make all the arrangements if they are able to provide transport for you.

Some local support groups and charities also provide hospital transport. If transport is very difficult, or you live a long way from the hospital, you may need to stay in a ‘hostel’ ward in the hospital or nearby. Sometimes it is possible for the hospital to organise local accommodation while you are having radiotherapy.

If you have difficulty meeting the cost of travelling to the radiotherapy clinic each day, you may be able to get a grant towards your travel expenses. People on a low income may be able to claim the costs from the Department of Work and Pensions or through the Hospital Travel Costs Scheme. Some charities (such as Macmillan Cancer Support) provide travel grants, and so do some local support groups.

You can ask the staff in the radiotherapy department, or a hospital social worker for information on transport costs, grants and advice on how to claim. See our financial issues section for information about benefits and financial help.

Before you have radiotherapy, your doctor will explain the aims of the treatment to you. They will usually ask you to sign a form saying that you give your permission (consent ) for the hospital staff to give you the treatment. No medical treatment can be given without your consent, and before you’re asked to sign the form you should have been given full information about:

• the type and extent of the treatment you are advised to have
• the advantages and disadvantages of the treatment
• any other treatments that may be available
• any significant risks or side effects of the treatment.

If you don’t understand what you have been told, let the staff know straight away so that they can explain again. Some cancer treatments are complex, so it’s not unusual for people to need repeated explanations.

It's often a good idea to have a friend or relative with you when the treatment is explained, to help you remember the discussion more fully. You may also find it useful to write down a list of questions before you go to your appointment.

Patients often feel that the hospital staff are too busy to answer their questions, but it’s important for you to be aware of how the treatment is likely to affect you. The staff should be willing to make time for you to ask questions.

You can always ask for more time if you feel that you can't makea decision when the treatment is first explained to you.

You are also free to choose not to have the treatment. The staff can explain what may happen if you don't have it. It's important to tell a doctor or the nurse in charge, so that they can record your decision in your medical notes. You don’t have to give a reason for not wanting to have treatment, but it can be helpful to let the staff know your concerns so that they can give you the best advice.

Possible pregnancy

Women of childbearing age will be asked whether they could be pregnant, as x-rays given during pregnancy could harm a baby. If you think that you may be pregnant, let the doctors and radiographers know immediately and you’ll be offered a pregnancy test.

Planning is a very important part of radiotherapy and may take a few visits. Careful planning makes sure that the radiotherapy is as effective as possible. It ensures the radiotherapy rays are aimed precisely at the cancer and cause the least possible damage to the surrounding healthy tissues. The treatment is planned by your clinical oncologist , a physicist and sometimes by a senior radiographer. You may have your first treatment on the same day as your planning session, but usually it’s necessary to wait a number of days, sometimes up to two weeks, while the team (physicist, oncologist or radiographer) prepare the final details of your treatment.

Positioning

During the treatment planning you will be lying on a fairly hard couch. Let the radiographer know if it is uncomfortable, as you can often be made more comfortable by having foam pads put underneath you. You have to lie very still for a few minutes so that accurate measurements can be taken and your exact position recorded. The radiographer can then make sure that you are lying in the correct position each time you have treatment.

To help you stay very still and keep your position during your treatment you may need a device called a 'mould'. This will be made before planning starts and is used to stop you moving so that the treatment is as effective as possible. Moulds are often used for treatments to the head and neck area. Sometimes a mould of your leg, arm or other body part is used to keep the area still during treatment. Marks can be made on the mould instead of your skin.

Moulds are commonly used for children having radiotherapy.

The mould is made of clear Perspex or a plastic mesh. The Perspex mould is made using a plaster cast that is first taken of the body part. This involves using strips of wet plaster bandage that are laid across the body. The plaster takes about five minutes to set. Some people may find this claustrophobic or a little frightening, especially if the mould is of the face and neck, but it only feels like this for a few minutes. After you leave the department, Perspex is moulded onto the cast to form a mask.

Some hospitals use a plastic mesh instead. The plastic mesh becomes soft in warm water and can be moulded to your body. It hardens after a few minutes and is then ready to use. Moulds covering the face will have holes cut for the eyes, nose and mouth.

Your mould should fit snugly and will be ready to wear at your first planning or treatment session. It may feel claustrophobic, but it can help to remember that you will only have a mould on for a few minutes at a time.

Our section on making a radiotherapy mask explains the process in more detail. 

On your first visit to the radiotherapy department you may have a CT (computerised tomography) scan taken of the area to be treated. A CT scan takes lots of images from different angles to build up a three-dimensional picture of the area. At the same time, therapy radiographers will take measurements from you which are needed for treatment planning. This session will usually take about 45–60 minutes. Sometimes you may also need to go to the hospital’s scanning department to have an MRI scan. This uses powerful magnetic fields to give a detailed picture of part of your body, which can give additional useful information.

The radiographer’s measurements and the information from the scans are fed into a planning computer that is used to help your doctors plan your treatment more precisely.

Some special procedures may be necessary to make sure the radiographers get a clear picture. The radiographer will explain these to you. To plan treatment to the pelvic area, for example, a liquid that shows up on x-ray may be passed into your back passage or into your bladder, or a tampon may be used to show the exact position of the vagina. These procedures may be slightly uncomfortable but aren’t painful and take only a few minutes. They are used only for planning the treatment, and not during the treatment sessions. It is important for you to feel that you are involved in your treatment, so feel free to ask as many questions as you like.

For some conditions, like many skin cancers and for palliative treatment, radiotherapy may be planned and given in a very simple way. Your specialist may simply put marks on your skin, with a soft pen, where the treatment is needed.

Once the treatment area has been finalised, ink markings are usually made on your skin (or on the mould) to pinpoint the exact place where the radiation is to be directed. The staff will explain how to look after these markings. If the marks begin to rub off, tell your radiographer. Do not try to redraw them yourself. The marks can rub off onto clothing, so some people choose to wear older clothes next to the skin during their treatment.

Often two or more tattoo marks are also made on the skin. These are permanent, but they are the size of a pinpoint and will only be done with your permission. It’s a little uncomfortable while the tattoo is being done, but it’s a good way of making sure that treatment is directed accurately. The tattoo marks are also useful once treatment has finished, as they show the area where the radiotherapy was given and prevent further radiotherapy being given there in the future.

Before your first treatment, the radiographers will explain to you what you will see and hear. It’s quite normal to feel anxious about having your treatment, but as you get to know the staff and understand what is going on it should become easier.

The sight of large radiotherapy machines can be frightening, especially for children. Don't be afraid to talk about any fears or worries to the staff; they are there to help you, and the more you understand about your treatment the more relaxed you will be.

Radiotherapy itself is painless and each session may take anything from a few seconds to several minutes. Because your positioning is so important, the radiographers may take a little while to get you ready (they may call this 'setting up'). The radiographers will position you carefully on the table and adjust the height and position of the table. The room may be in semi-darkness while this is happening.

Once you are in the correct position the staff will need to leave you alone in the room, to prevent them from being exposed to any unnecessary radiation. Don't worry if the staff seem to rush out of the room once they have positioned you - this is just to keep your treatment time as short as possible. Radiotherapy units have many people to treat and the staff need to keep appointments on time.

Some treatment rooms have CD players so that you can listen to music to help you relax while having your treatment. During treatment you will be alone for a few minutes but there will often be an intercom so that you can talk to the radiographers.

They will be watching you carefully from the next room, either through a window or on a television screen. To protect your privacy, nobody else will be able to see you. If you have any problems, you can raise your hand to attract the radiographer’s attention and they will come in to help you.

Most radiotherapy machines will be able to rotate around your body to give the treatment from several different directions. This and the sound of the machine can be unsettling at first.

The radiographers may have to come into the treatment room to change your position slightly in the middle of your treatment. Small changes sometimes have to be made to your treatment plan. There may be various reasons for this. Your specialist and the radiographers will explain any changes to you.