Decorative image

Planning radiotherapy

The radiotherapy team plan your external beam radiotherapy before you start treatment. This means working out the dose of radiotherapy you need and exactly where you need it.

Your planning appointment takes from 15 minutes to 2 hours.

You usually have a radiotherapy mould (shell) done first. You then have a planning CT scan.

Radiotherapy mould (shell)

Your treatment team might make a mould (shell) for you.

You wear it during the treatment sessions to keep you very still. The radiographers may also make marks on it. They use the marks to line up the radiotherapy machine for each treatment.

The process of making the shell can vary slightly between hospitals. It usually takes around 30 minutes.

Before making the shell

You need to wear clothes that you can easily take off from your neck and chest. You also need to take off any jewellery from that area.

Facial hair, long hair or dreadlocks can make it difficult to mould the shell. The radiotherapy staff will tell you if you need to shave or to tie your hair back.

Making the shell

A technician uses a special kind of plastic that they heat in warm water. This makes it soft and pliable. They put the plastic on to your face, neck and chest so that it moulds exactly. 

After a few minutes the plastic gets hard. The technician takes the shell off and it is ready to use.

Radiotherapy mask

You may also have a dental impression made with gel. The technician puts the gel into your mouth and takes an impression of your teeth. This takes between 5 and 10 minutes. The technician also makes an impression of your lower jaw and neck. The whole visit takes about 30 minutes.

Planning CT scan

You usually have a planning CT scan in the radiotherapy department.

The scan shows the cancer and the area around it. You might have other types of scans or x-rays to help your treatment team plan your radiotherapy. The plan they create is just for you.

Photo of a CT scanner

Your radiographers tell you what is going to happen. They help you into position on the scan couch. You might have a type of firm cushion called a vacbag to help you keep still.

The CT scanner couch is the same type of bed that you lie on for your treatment sessions. You need to lie very still. Tell your radiographers if you aren't comfortable.

Injection of dye

You might need an injection of contrast into a vein in your hand. This is a dye that helps body tissues show up more clearly on the scan.

Before you have the contrast, your radiographer asks you about any medical conditions or allergies. Some people are allergic to the contrast.

Having the scan

Once you are in position your radiographers put some markers on your skin. They move the couch up and through the scanner. They then leave the room and the scan starts.

The scan takes about 5 minutes. You won't feel anything. Your radiographers can see and hear you from the CT control area where they operate the scanner. 

After your planning session

It can take a few days or up to 3 weeks before you start treatment.

Your radiographers and doctors create your radiotherapy plan. They make sure that the area of the cancer will receive a high dose and nearby areas receive a low dose. This reduces the side effects you might get during and after treatment. 

Radiotherapy treatment

You might have radiotherapy for salivary gland cancer on its own or after surgery. 

Last reviewed: 
25 Oct 2019
  • Management of Salivary Gland Tumours: United Kingdom National Multidisciplinary Guidelines

    S Sood and others

    The Journal of Laryngology & Otology, 2016. Vol 130, Supplement S2

  • Principles and practice of oncology (11th edition)
    V DeVita, T Lawrence and S Rosenberg
    Wolters Kluwer, 2018

  • Cancer and its Management (7th edition)

    J Tobias and D Hochhauser

    Wiley Blackwell, 2015

  • External Beam Therapy
    Peter Hoskin
    Oxford University Press, 2012

Information and help