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Planning radiotherapy

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

Radiotherapy uses high energy waves similar to x-rays to kill cancer cells.

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

You might need to lie with your arms above your head when you have radiotherapy. If this is not possible for you, your radiographer will help you to find a suitable position. You will need to lie in the same position during each treatment.

You may need an injection of contrast for your CT scan. 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.

The radiographers put some markers on your skin. You need to lie very still.

Once you are in position the radiographers move the couch up and through the scanner. The radiographers leave the room and the scan starts.

The scan takes about 5 minutes. You won't feel anything. The radiographers watch from the next room.

Before the planning appointment you might also have other scans, such as an MRI scan.

Ink and tattoo marks

The radiographers might make pin point sized tattoo marks in the treatment area. These make sure they treat exactly the same area every day. They may also draw marks around the tattoos with a permanent ink pen. This highlights the tattoos and makes them look like small crosses.

Radiotherapy tattoo marks
Radiotherapy treatment area marks.

The radiotherapy unit staff tell you how to look after the markings. The pen marks might start to rub off in time. If that happens, tell your radiographer. Don't try to redraw them yourself. 

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 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 might have a mould made if your cancer is in the upper part of your lung.

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.

Information and help

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About Cancer generously supported by Dangoor Education since 2010.