Planning radiotherapy for laryngeal cancer
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.
Before you have your radiotherapy you usually have a radiotherapy mask made of your head and neck first. You then have a planning CT scan.
Radiotherapy mask (mould or shell)
You usually have a mask if you have radiotherapy for laryngeal cancer. You might also hear this called a mould or shell. The mask keeps you perfectly still while you have treatment. 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 mask can vary slightly between hospitals. It usually takes around 30 minutes.
Before making the mask
The mask is normally made directly against your skin. It's helpful to wear clothing that you can easily take off. You also need to take off any jewellery from that area.
Having a lot of facial hair can make it difficult to make a head and neck mask. The radiotherapy staff will advise you about any hair issues.
Making the mask
A technician or radiographer makes the mask in the mould room of the radiotherapy department or during your CT planning scan.
The process of making a mask can vary slightly between hospitals. Most often they use a special kind of plastic heated in warm water or an oven so that it becomes soft and pliable.
Your technician puts the plastic mesh on your face so that it moulds to fit your face exactly. It feels a little like having a warm flannel put onto your face. You can still breathe easily, as the plastic has lots of holes in it. The staff explain what is going to happen.
After a few minutes the plastic mesh becomes hard. Your technician takes the mask off. It is then ready for use.
The video below shows what happens when you have your mesh mask made. The video is about 1 and a half minutes long.
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: Okay, you are just going to feel us pressing down on the mask there; you are doing really well are you still okay?
Patient: Mmm...
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 um told me about the procedure, a mask being fitted, uumm that it would be moulded to the shape of my face. Umm which they did, three lovely girls umm put my mind at ease, sat me down, heated the mask, moulded it around my face, um not an uncomfortable thing at all to go through.
The 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.
The scan
You lie on the scanner couch. Your radiographers will tell you if you need to remove any clothes. They need to see the treatment area, but will cover you up as much as possible. You have the mask in place for your planning scan.
You have to lie as still as you can, so that the measurements are accurate and the radiographers can record your exact position. This means they can make sure you are lying in the correct position every time you have treatment. Tell the radiographers if you are uncomfortable.
Once you are in position the radiographers move the couch up and through the scanner. The scanner is a doughnut shape. Your radiographers leave the room and the scan starts. It 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.
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 medium, the radiographer asks you about any medical conditions or allergies. Some people are allergic to the dye.
Watch our video about radiotherapy planning. It is just under 3 minutes long.
Dan (radiographer) : Radiotherapy planning will involve you coming for an appointment for a CT scan in the radiotherapy department. The idea behind this is that the doctor needs to work out exactly where needs to be treated and where we need to avoid and so that scan starts us off on that process.
For the CT scan, most of the time no preparation is needed beforehand but if any is then you’ll receive that in a letter so for example, depending on what you having treated there might need to be a contrast agent introduced or you may need to have a full or an empty bladder depending on what is necessary for the scan. There are a number of things we do to help people keep still and make sure the cancer is treated.
It is important that you lie in the same position every time you have treatment. This is to make sure the radiotherapy is directed at the cancer and normal tissues are avoided. We may put equipment in place to fix your position. If you are having radiotherapy for a head and neck cancer you will have a mask made. The mask helps you to keep your head really still during treatment. We also line up the scanner and mark your skin with a felt pen where the light lines from the machine need to be aimed.
They’ll then leave the room and start the scanner and that scan lasts usually about 2 to 3 minutes. Because pen marks can rub easily the radiographer makes them permanent after your scan by tattooing very small marks on your skin.
After the scan the radiographers will give you any information that you need before starting treatment and answer any questions that you’ve got then you are free to go home.
Patient: When I came for the first meeting to plan the treatment. It was a case of having a scan and then lying, remaining on the scan machine and then the technicians took some measurements some dimensions and when they were satisfied that they had the right angles they tattooed me.
Dan (radiographer): The next part of planning is your doctor looking at the scan and marking out on the computer where you need treatment. Once that’s been done a physicist or a dosimetrist will start to plan your treatment. And they use very powerful computers to work out exactly what dose needs to be given and from which directions it needs to come on from.
When you finish your planning appointment your radiographers will help you off the CT scanner couch. Then you can get changed back into your clothes. You stay in the department for about 15 to 30 minutes if you had an injection of the dye. This is in case it makes you feel unwell, which is rare.
You should be able to go home or back to work. You can eat and drink normally.
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 radiotherapy 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.
