Introduction to External beam radiotherapy
External Beam Radiation Therapy (EBRT) is a common type of radiotherapy treatment. It uses high energy radiation in the form of photon beams to destroy the DNA of cancer cells. It is given using a machine called a linear accelerator.
Although EBRT uses radiation, it will not make you radioactive. This is because the radiation does not stay in your body during or after treatment.
Typically, you will travel to a hospital each weekday to have treatment. Then go home shortly after. Treatment times vary, depending on what you are having and what preparations you need to do. Often you will be treated on the linear accelerator for just a few minutes.
A course of this kind of radiotherapy usually happens from Monday to Friday over one to seven weeks. Each treatment plan is tailored to:
- You as a unique person and patient
- the type of cancer
- where the cancer is
- how much it has grown or spread
External beam radiotherapy does not usually need a stay in hospital. However, there may be times when that is needed, if you need more care or are very unwell. Patients often do feel unwell during treatment, but on rare occasions this can be more severe.
Preparing for radiotherapy with a scan
Your treatment team will discuss EBRT as an option for you. They will look at what you need and then make a plan just for you. Your team will give you your treatment and support you with any side effects.
Before treatment starts, you need a planning CT scan so your treatment team can map out the treatment. This scan is carried out by therapeutic radiographers. You might already have had multiple diagnostic scans before this, to reach a diagnosis. However, the radiotherapy CT scan is needed to plan a radiotherapy treatment that is right for you.
Finding the right position for your scan
Your Therapeutic radiographers are there to guide you through the pre-treatment planning session and to answer any questions you may have. You will need to take off clothing around the area that needs treatment. You may need to have some small tattoos or markers made on your skin that will appear on the CT scan. Your team use these as reference points to make sure your treatment is accurate. Radiotherapy treatment is given to the same area each day so your treatment team need to plan a position for you that can be recreated each day of the treatment. Some radiotherapy departments have equipment they use instead of tattoo markers to help with getting you in the position needed for treatment.
Immobilisation devices for your scan
This careful planning is part of the reason treatment is so accurate. During the planning appointment, your treatment team might need to create an immobilisation device. These are pieces of equipment that help to support you to keep still. They can include masks, vacuum bag cushions and equipment to aid in comfort and support.
You might need a contrast injection for your scan
During the scan you may need to have an injection. The contrast agent injected is a material that makes the inside of your body easier to see on the scan images. Again, this helps your treatment team plan your treatment accurately.
Further preparation
The images created by your CT scan are used by the treatment team to map out where the radiotherapy needs to target.
You may need to prepare for the scan before coming to the hospital. For example, you might need to have a full or empty bladder or empty your bowels. Your treatment team will give full instructions before your scan so you know what to do.
Unless you start treatment on the same day, you can go home after your planning scan. If you are having treatment on the same day, you will need to wait until your treatment plan is made. You might want to take something to read or listen to, to help pass the time.
Planning behind the scenes
Your Multidisciplinary Team will decide on the best way to plan and deliver your radiotherapy. This can take from a few hours to a few weeks depending on how complicated it is. Once the treatment plan has been made, multiple checks need to be made by your treatment team. These checks all happen behind the scenes, and you do not need to be there. Your treatment will not start until all of this is done.
Learn more about your treatment team and how they plan
First day of treatment
On the first day of treatment your treatment team will talk through the plan with you, so you know what to expect. This is a great chance to ask any questions.
Take a look at these suggested questions
You can usually take a friend or relative with you to this appointment. This can be really helpful as they can also ask questions and help remember or write down answers if you are feeling nervous or overwhelmed.
Then you will be taken through to the treatment room. You’ll remove or arrange your clothes as you did for your planning CT session. Your team will then help you into the right position. Your therapeutic radiographers will then leave the treatment room to operate the radiotherapy machine (known as a Linear accelerator or Linac). Radiotherapy machines deliver pinpoint accuracy to the treatment area. They have the ability to shape the radiation to the target and avoid healthy tissues and sensitive structures within the body.
What to expect
You will be on your own while the treatment happens. Your treatment team can see into the treatment room using cameras at all times. They can talk to you through an intercom if needed.
The therapeutic radiographers make sure the machine delivers the radiotherapy according to your treatment plan. This can involve taking images to check the treatment accuracy. Small adjustments can be made to fine-tune your position. When the treatment is happening, the radiotherapy machine can be still or move around you.
Treatment can typically take from 10 minutes up to an hour. You will not feel any pain from the treatment as it happens. After the treatment session is finished you can go home soon after.
You need to try and keep as still as possible for each treatment. If you do move – don’t worry – your team understand and can pause the machine. Some treatments may involve special instructions, such as holding your breath.
Learn more about Deep-Inspiration Breath Hold technique
Any special instructions will be discussed before your treatment.
Support during and after treatment
Throughout EBRT, you are closely monitored by your treatment team. The team will provide support and advice on managing any side effects during this time. Once radiotherapy is complete, you should be given information to support your recovery. You should be given contact details if you have any problems or questions. Many charities, local, regional and national, offer support for people that have had cancer treatment.
Other types of external beam radiotherapy
- Deep X-Ray Therapy [DXT] or Orthovoltage X-rays: This is radiotherapy that uses a lower energy radiation to treat cancer on or close to the skin surface. The radiation can be a lower energy as it does not need to go into the body as deeply.
- Electron Therapy or Electron Beam Therapy (EBT): This uses electrons instead of photons to deliver a radiation dose to the target. Electrons do not penetrate the body as deeply as photons. They are used to treat tumours that are closer to the surface of the skin. These can include cancers near the nose, eyes, ears and lips.
- EBT can also be used for some people that have had a breast tumour removed (lumpectomy) to reduce the chances of the cancer coming back.
- EBT is useful because it does not impact deeper tissues unnecessarily. Like external beam radiation therapy, EBT is given using a machine called a linear accelerator, but with extra equipment attached.
- Cyberknife
- MRI LINAC
Particle therapy
Particle therapy is another form of external beam radiotherapy. Read more about it here.
