A study looking at using PET-CT scans to plan radiotherapy in people with cancer of the head and neck (POSITIVE)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Head and neck cancers
Mouth (oral) cancer





This study is looking to see if PET-CT scans can help plan radiotherapy even more accurately. When radiotherapy doctors (clinical oncologists Open a glossary item) plan your radiotherapy, an important part is to work out the size of the cancer they need to treat. They usually use CT scans and MRI scans to help them do this.

Researchers in this study are looking to see if a PET-CT scan can help with the planning process. PET-CT scans use a radioactive substance to show up chemical reactions in the body. The researchers think that a PET-CT scan may help doctors to more accurately work out the size and exact place the cancer is in the body. This would improve how accurate and successful the radiotherapy would be. The PET-CT scan may also be able to pick up any other areas of cancer that may not have shown up on a regular CT scan.

People taking part in this study will have a PET-CT scan as part of their radiotherapy planning, instead of a CT scan. The aim is to find out how PET-CT scans can be used to measure tumour size in people with cancer of the head and neck.

Who can enter

You may be able to enter this study if you are being cared for by doctors at Velindre Cancer Centre in Cardiff and you

You cannot enter this study if you are pregnant or breastfeeding.

Trial design

This study will recruit 20 people. Everyone taking part will have a PET-CT scan, instead of a CT scan, when they have their radiotherapy planning.

When you arrive for your PET-CT scan, the staff will ask you to drink some water. You then have an injection of a small amount of radioactive tracer, which helps the scan pictures show up more clearly. And then you lie down and relax while your body absorbs the tracer.

Before the scan the staff will ask you to empty your bladder in the toilet. You then have the scan, which takes about 30 minutes.

You are free to leave the department after your scan. But, because of the tracer injection, you should avoid close contact with young children or pregnant women for 8 hours after your scan. Close contact in this case means picking up or sitting close to someone.

The team may ask if they can contact you again in future if they have any more research that may be suitable for you to take part in. You do not have to agree to this if you don’t want to.

Hospital visits

For the study, you will have a PET-CT scan as part of your radiotherapy planning, instead of a CT scan.

You have the PET-CT scan at the University Hospital of Wales, Heath Park and your appointment will take between 2 to 4 hours. This is because the radioactive injection takes time to work its way round your body before the scan. The actual scan will take about 30 minutes.

Side effects

You will be exposed to a very small amount of extra radiation for the study PET-CT scan. But this extra dose is a thousand times smaller than the dose you will have to treat your cancer.

The radioactive tracer injection from this PET-CT scan leaves the body quickly in your urine. You should not feel any side effects after the scan.

It is possible that the study PET-CT scan could pick up some tiny areas of cancer spread that hadn’t shown up on a regular CT scan, because they are so small. If this happens, the study team will talk to your doctor so that they can treat this.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Dr Emiliano Spezi
Dr Mererid Evans

Supported by

Cancer Research Wales
National Institute for Health Research Cancer Research Network (NCRN)
Velindre NHS Trust

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 10701

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Charlie took part in a trial to try new treatments

A picture of Charlie

“I think it’s really important that people keep signing up to these type of trials to push research forward.”

Last reviewed:

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