Overview

Before your radiotherapy starts, you’ll have a CT scan to help plan your radiotherapy treatment.

A CT scan uses X-rays to give a detailed image of the inside of your body. It's much more detailed than an X-ray, and generates 3D images.

Before the CT scan

If you're between the ages of 12 and 55, we'll ask if you’re pregnant. If there is a chance you could be pregnant, you'll need to tell the radiographer. This is because we might not be able to do the CT scan if you're pregnant.

We'll give you a gown to wear for your CT planning scan. We'll also give you one for your treatment appointments.

Length of the appointment

The appointment should last about 2 hours. You might want to bring something to eat and drink with you, especially if you have diabetes.

Giving your permission (consent)

We want to involve you in decisions about your care and treatment. If you decide to have the procedure or treatment, we will ask you to sign a consent form. This says that you understand what is involved and agree to have the treatment.

Read more about our consent process.

During the CT scan

For the scan, you will be asked to lie on a flat bed. The scan is done by radiographers. They'll move you into the position that you'll need to be in for all of your radiotherapy treatments.

The bed will move slowly through the CT scanner. A CT scanner is shaped like a large ring, and you will go through the hole in the middle.

You will not feel anything and nothing will touch you. Your radiographer might give you instructions to hold your breath during the scan, to help us get the best images possible.

You can tell the radiographers if you feel uncomfortable at any time, or if you have any concerns.

CT scans with contrast

Your doctor might have asked us to give you CT scan with a contrast (dye) to help us see inside your body more clearly. A contrast liquid will be injected into a vein in your arm, or you might drink a small amount of it with some water. Your doctor will decide the best way to get the contrast into your body.

You might also have a blood test before your planning appointment. This is to check that your kidneys are working well.

It’s not always possible to use the contrast dye, for medical reasons or if we cannot get access to your veins.

Some people get side effects from the contrast. The most common side effects are a feeling of warmth in your body, and a metallic taste in your mouth.

Other side effects include:

• feeling sick (nausea)
• being sick (vomiting)
• an urge to pee while the dye is given
• headache
• high or low blood pressure
• diarrhoea

Allergic reactions

Allergic reactions to the contrast dye are rare.

If you have any questions or would like more information on the possible side effects of the contrast, please ask your radiographer before your scan.

After the CT scan

After the scan the radiographers will take some measurements and might put some small, permanent marks on your skin. This is to help position you correctly for your radiotherapy treatments.

If you have been given the contrast dye, you’ll need to stay in the department for about 15 minutes. This is to check if you feel unwell or get any side effects. If you start to feel unwell, tell a radiographer immediately. You should monitor your symptoms when you leave the hospital.

After leaving hospital

You should monitor your symptoms when you leave the hospital.

Travel fares and transport

You might be able to claim back your fares to the hospital. You can ask if you're eligible for this at the radiotherapy reception.

If you need help with hospital transport, contact the hospital transport team, phone: 020 7188 2888. The radiographers cannot arrange this for you.