Planning radiotherapy for soft tissue sarcoma

Radiotherapy uses high energy rays to treat cancer. You have external beam radiotherapy for soft tissue sarcoma. This means directing radiotherapy beams at the cancer from outside of the body. 

When you have radiotherapy depends on what other treatments you are having for your sarcoma.

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

The radiographers tell you what is going to happen. They help you into position on the scan couch.

You might have a firm cushion called a vacbag or a mould (shell) to keep the treatment area still. This keeps the area still and makes sure that you have treatment to the exact same area each time.

The CT scanner couch is the same type of bed that you lie on for your treatment sessions. Tell the radiographers if you aren't comfortable.

Having the scan

The radiographers 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. 

Radiotherapy mould (shell)

Your team might make a mould (shell) for you to keep the treatment area very still. For example, you might have a mould over an arm or leg, or your head and neck, depending on where your sarcoma is. A mould for the head and neck area is also called a mask.

The process of making the mould can vary slightly between hospitals. It usually takes around 30 minutes.

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 the area 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.

You might have the mould made before or during your planning session. 

Photograph of radiotherapy mould of a leg

Ink and tattoo marks

The radiographers make pin point sized tattoo marks on your skin, or marks on the mould. Or you might have marks on both your skin and the mould. These help to line up the radiotherapy machine for each treatment.

They may also draw marks around the tattoos on your skin with a permanent ink pen. This is so they are clear to see when the lights are low.

Photograph of radiotherapy tattoo marks

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

You may have a mould made to keep your arm or leg perfectly still. If you have a mould made the staff may make the radiotherapy markings on the mould instead of on your skin.

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. 

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