You have a planning session with your radiotherapy team a few days or weeks before you start treatment.
What happens at your planning session
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.
Your radiographers make a treatment shell (mask) first. There is more information about this below.
Once you are in position on the scanner couch your radiographers move it up and through the scanner. They then leave the room and the scan starts. You need to lie very still during the scan.
The scan takes about 5 minutes. You won't feel anything. Your radiographers watch from the room next door and you can talk to them on an intercom if you need to.
Before the planning appointment you might also have other scans, such as an MRI scan. Your treatment team puts all the scans together in a special computer to decide your radiotherapy plan.
Radiotherapy mould (shell)
Your treatment team will make a mould (shell) of your head and neck. You wear it during the treatment sessions to keep you very still.
Your 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. Your radiotherapy team 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, 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.
The video below shows what happens when you have your mesh mask made:
Voiceover: Making a mesh mask for radiotherapy takes a few minutes.
Radiographer: I am just going to heat this up now. If you just keep nice and still there, and just want to close your eyes for us.
Voiceover: The radiographer softens the mask by putting it in warm water for a minute or two. When the radiographer puts the mask on to your face it will feel warm and damp. They then clip it to the bed that you are lying on. It takes a minute or two to dry into the shape of your face. The radiographers will mark the mask where the light lines are.
Radiographer: OK, you are just going to feel us pressing down on the mask there. You are doing really well - are you still ok?
Voiceover: They use the marks on the mask to line up the machine each time you have treatment. The mask keeps your head still and makes sure that your treatment is directed at the cancer. They put your name on the mask and keep it in the radiotherapy department ready for your treatment.
Patient: They told me about the procedure; a mask being fitted, that it would be moulded to the shape of my face. Which they did. Three lovely girls put my mind at ease, sat me down, heated the mask, moulded it around my face - not an uncomfortable thing at all to go through.
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.