Planning external radiotherapy

You might have external radiotherapy for a neuroendocrine tumour (NET) that has spread to other parts of the body such as the bones and the brain. It can control your symptoms and help you feel better.

Planning your treatment

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 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. 

Making a mould or shell

You need to keep still during radiotherapy. If you have radiotherapy to the brain, your treatment team might make a mould (shell) for you to wear during the treatment sessions. The shell covers the whole of your face and the front of your head. And it attaches to the scanner or radiotherapy machine bed while you are wearing it. This means that you can’t move, but there is nothing attached to you directly.

The radiographers may also make marks on the shell. 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. 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 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 and neck so that it molds exactly.

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

After your planning session

You might have to wait a few days or up to 3 weeks before you start treatment.

During this time the physicists and your radiographer doctor (clinical oncologist) decide the final details of 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. 

Last reviewed: 
22 Mar 2021
Next review due: 
21 Mar 2024
  • Gastroenteropancreatic neuroendocrine neoplasms: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up
    M. Pavel and others
    Annals of Oncology 2020, Vol 31, Issue 5 

  • Guidelines for the management of gastroenteropancreatic neuroendocrine tumours (including carcinoid) tumours (NETs)
    J Ramage and others
    Gut, 2012. Vol 61, Pages 6-32

  • External Beam Radiotherapy in the Treatment of Gastroenteropancreatic Neuroendocrine Tumours: A Systematic Review
    DL Chan and others
    Clinical Oncology, 2018. Vol 30, Pages 400-408

  • Radiation Therapy in the Management of Patients with Malignant Carcinoid Tumors
    A Chakravarthy and RA Abrams
    Cancer, 1995. Vol 75, Number 6, Pages 1386-1390

Related links