Radiation Therapy (RT)

Radiation therapy (also called radiotherapy) uses radiation (high-energy rays) to kill or shrink tumour cells.

What is RT?

About this treatment

Radiation therapy, or radiotherapy, is used to treat some, but not all, cancers. About half of patients with cancer get radiation therapy as part of their treatment.

Radiation therapy can be used to try to cure cancer, reduce the chance of it coming back, or to help relieve symptoms. You might have it by itself or with other treatments such as surgery, chemotherapy, or hormone therapy.

Most radiation therapy is delivered by a machine from outside of the body (external radiation therapy). Radiation therapy can also be delivered from inside the body, called internal radiation therapy or brachytherapy. Your radiation oncologist will decide which type you need.

For additional information, click "+" on the topics below.

How it works

Radiation destroys cells in the treatment area. It does this either by destroying the cell directly or by damaging its DNA so that it cannot grow anymore. Cancer cells are more sensitive to radiation than normal cells.

It is very hard to destroy cancer cells without damaging some normal cells too. Damage to normal cells causes side effects. However, normal cells can recover from radiation damage better than cancer cells.

The goal of radiation therapy is to give enough radiation to destroy the cancer cells in your body, but not enough that your normal cells cannot recover.

Find out more about radiation therapy side effects here.

Your course of treatment

When deciding on your course of treatment your radiation oncologist considers:

Your type of cancer
Where it is in the body
Other treatments you’ve had, are having, or going to have
Your general health and fitness

Radiation therapy with the goal of curing cancer or reducing the chance it can come back can last between 1 to 7 weeks.

If the goal for your treatment is to relieve symptoms, you might have anything from a single treatment to 2 weeks of treatment.

Most people have one treatment daily from Monday to Friday, with a rest on weekends and holidays.

However, these scenarios can vary. For example, you might have treatment once a week for a few weeks, or more than one treatment per day. You might also have treatment on the weekend. Your doctor will confirm your treatment schedule.

Treatment appointment times are usually not the same every day. Let someone on your care team know if you need a specific time window for your appointments. They will try to accommodate, but it can be difficult depending on how busy the department is.

Worries about treatment

You may feel anxious about your radiation therapy treatment. This is completely normal.

It can help to talk through any worries you have with your radiation oncologist, nurse, or radiation therapists. We also offer counselling services with health professionals. They can help you cope with emotions and concerns about your treatment.

Find out more about the other services and support programs we offer here to help you through your cancer care journey.

Having RT

Whether you have radiation therapy as part of your treatment depends on:

what type of cancer you have
how big your cancer is
if your cancer has spread or not.

Find out more about when and where you might have radiation therapy, who gives it, and what your treatment journey might look like.

For additional information, click "+" on the topics below.

When you might have RT

Radiation therapy is used for two main reasons: to try to cure cancer (radical or curative) or to help control symptoms (palliative).

Your radiation oncologist will decide whether or not you should have radiation therapy as part of your treatment. It depends on what type of cancer you have, how big it is, and whether it has spread or not.

You might have radiation therapy:

Before surgery
After surgery
As part of a bone marrow transplant
Together with chemotherapy
By itself

Where you might have RT

Radiation therapy is usually given as an outpatient. For external radiation therapy, you will travel to the radiation therapy department at your nearest regional cancer centre. You will go home after your treatment.

For some types of internal radiation therapy (or brachytherapy), you might have to stay in the hospital overnight. If you’re already staying in the hospital, your hospital care team will arrange your transportation to the radiation therapy department.

Some types of radiation therapy are only offered in specific regional cancer centres. If you need a type of treatment that is only offered at a centre far from home, talk to your radiation oncologist about where you can stay.

Find out more here about your options for transportation and lodging.

Who gives RT?

Doctors who specialise in treating cancer with radiation therapy are called radiation oncologists.

Your radiation oncologist works with other health professionals who have been trained in cancer treatment and care. Your health care team during your radiation treatment will include:

A radiation oncologist
Radiation therapists
Medical physicists (specialists who help make the radiation treatment plan)

Your primary team is responsible for designing, planning, and delivering your radiation treatment plan safely and effectively. You will see radiation therapists every day for your treatment appointments. You will see your radiation oncologist at least once during your treatment course.

Other members of your health care team may include:

Nurses
Dietitians
Speech language pathologists
Medical oncologist
Surgeon
Physiotherapists

Your treatment pathway

Once you and your radiation oncologist have decided that you will have radiation therapy treatment, the planning process will start.

To plan your treatment your radiation oncologist needs to see where the cancer is and the area around it. Usually, this means you will have a planning CT simulation appointment in the radiation therapy department.

At this appointment, you will lie down on the CT scanner bed. The radiation therapists will position you. Please tell the radiation therapists if you are uncomfortable. You will have to lie in this exact position each time you have your radiation treatment.

Depending on what area of your body is being treated, you may also need:

A mould or mask(shell) to keep you perfectly still
IV contrast (dye) injection to help see the cancer or blood vessels better
Permanent tattoos (the size of a freckle) to help put you in the right position

After the CT simulation appointment, the radiation oncologist, radiation therapists, and medical physicist will plan your treatment.

Once your treatment plan is completed, a radiation therapy clerk will call you with the date and time of your first treatment. On that day, the radiation therapists will sit down with you to explain the process and answer your questions.

Types of RT

There are many types of radiation therapy. Depending on your cancer type, stage of your cancer and how you are feeling, the radiation oncologist will decide what type of radiation therapy is right for you. The two main types of radiation are external beam radiation and internal radiation, or brachytherapy.

Click "+" on the topics below for a description of brachytherapy and different types of external beam radiation.

External Beam Radiation Therapy (EBRT)

External beam radiation treatments are given on a machine called a linear accelerator. This machine uses electricity to create the radiation beams.

For all of the techniques described below, you will need a planning CT scan prior to treatment (See Your Treatment Pathway (please see "Your treatment pathway" on the "Having RT" tab for more information). You may also need other types of scans such as MRI or PET.

Your radiation therapists may also take additional images (e.g. scans and x-rays) to make sure that your position is correct before giving the radiation each day. This is called image-guided radiation therapy, or IGRT, and is often built into most radiation techniques in BC.

Intensity Modulated Radiation Therapy (IMRT)

Intensity modulated radiation therapy, or IMRT, is radiation therapy where the shape of the radiation field changes as treatment is delivered. The radiation field is shaped so that the tumour, or where the tumour was, can get a high dose, while the normal tissue is avoided.

Volumetric Modulated Arc Therapy (VMAT)

Volumetric Modulated Arc Therapy, or VMAT, is a form of intensity modulated radiation therapy (IMRT). The big difference with VMAT is the treatment machine moves around you in a circle as the radiation is given. This machine motion allows for further shaping of the field.

3D Conformal Radiation Therapy (3DCRT)

3D conformal radiation therapy, or 3DCRT, is radiation therapy given to closely fit the treatment area. First, the radiation oncologist decides what area needs to have treatment. The radiation beams are then shaped to match this area. The beams from the treatment machine are also angled to target the treatment area and avoid healthy tissue.

Stereotactic Radiation Therapy

Stereotactic radiation therapy uses special equipment to position the patient. There are two types of special equipment: masks and body moulds (a hard cushion fitted to your body). This equipment allows us to give radiation in a more precise way. When we use this equipment, we can give higher doses of radiation with each treatment.

Stereotactic Radiation Therapy is not appropriate for all types of cancers or tumour locations.

When stereotactic radiation is delivered to the body (lung, liver, bone, etc.), it is called stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy (SABR). This radiation is delivered in 3 to 8 treatments. The treatments might not be every day, but may be spaced out with a day in between treatments.

If you need a body mould, this will be created during the radiation planning process. You may also need a mask, or shell, around your head and shoulders.

When stereotactic radiation is delivered to the brain, it is either delivered in one of two ways:

a single treatment called stereotactic radiosurgery (SRS), or
multiple treatments, called stereotactic treatment (SRT).

For stereotactic treatments to the brain, a specialized mask is created that keeps your head very still. This mask will be tight but shouldn’t be uncomfortable.

Internal Radiation Therapy (Brachytherapy)

Brachytherapy is widely used to treat many types of cancer. Brachytherapy is when refers to radioactive "seeds" or "sources" are placed inside, or next to, a tumour. The sources give radiation directly to the tumour. This makes sure that surrounding healthy tissues gets as low a radiation dose as possible.

Radioactive sources may be left in the body permanently or taken out after treatment is over. It depends on what type of tumour is being treated. Even for those treatments that involve permanent implants, the amount of radiation detected outside the body is very small.

Brachytherapy may affect fewer healthy cells. This may lead to fewer side effects for you. The side effects will depend on the area being treated. You may have brachytherapy alone or with external beam radiation.

Brachytherapy is planned using an ultrasound, CT or MRI scan. The radiation oncologist will use the scan to determine how much radiation you need and where to put the radioactive sources.

When you get brachytherapy, you will likely need general anesthetic. However, this is usually an outpatient procedure where you don’t need to stay in the hospital overnight.

If you would like more information on prostate brachytherapy, watch these videos below. Please note that even though BC Cancer oncologists are shown in these videos, they are not official BC Cancer education materials. We thank the creators of these videos for sharing the content.

1. Introduction to Brachytherapy featuring Dr. Saibishkumar Elantholi Parameswaran (video produced by Princess Margaret Hospital/University Health Network, Toronto).