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Planning radiotherapy

Find out what happens at your planning appointment for external radiotherapy.

Planning your treatment

The radiotherapy team plans your external beam radiotherapy before you start treatment. This means working out how much radiation you need to treat the cancer and exactly where you need it. Your planning appointment takes from 15 minutes to 2 hours.

You have a planning CT scan in the radiotherapy department. The scan shows the cancer and the area around it.

Photo of a CT scanner

When you arrive for your appointment the radiographers will tell you what is going to happen. They will help you into position on the scan couch. You might have a type of firm cushion called a Vac pac 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 the radiographers if you aren't comfortable.

Once you are in position the radiographers put some markers on your skin. They will 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. The radiographers can see you from the CT control area where they operate the scanner. 

Your treatment team use different scans and sometimes x-rays to help them plan your treatment.

Your treatment team puts all the scans together in a special computer to decide your radiotherapy plan. 

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 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

After your planning session

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

During this time your radiologists and doctors create your radiotherapy plan. They make sure that the area of the cancer will receive a high dose and surrounding areas receive a low dose.

Removing teeth and putting in dental implants

You may need to have some or all of your teeth removed before your radiotherapy treatment. You might also need to have dental implants put in during or after your radiotherapy. 

Your restorative dentist will talk this through with you before your radiotherapy. They will be happy to answer your questions. They will be aware that you may be very worried and upset about having your teeth removed. Don't be afraid to find out all you need to. You might find it easier to cope if you understand exactly what is going to happen. 

Last reviewed: 
30 Sep 2014
  • The Royal Marsden Hospital Manual of Clinical Nursing Procedures (8th Edition) 
    L Dougherty and S Lister (Editors)

    Wiley-Blackwell, 2011   

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