Planning radiotherapy for soft tissue sarcoma

Radiotherapy uses high energy x-rays to kill cancer cells. External beam radiotherapy is the use of radiation to destroy cancer cells from outside of the body.

The radiotherapy team plan your radiotherapy before you start your treatment for soft tissue sarcoma. 

Planning your treatment

The radiotherapy team plan your external 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.

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. 

Vacuum bag mould

A vaccum bag mould is used during your treatment to help keep you still and in the right position.

Your radiographer might make a mould using a plastic cushion filled with tiny polystyrene balls. They mould the cushion around the treatment area and then suck out the air with a vacuum pump.

This moulds the cushion very closely around your body and the radiographer removes the pump. The cushion then forms a solid and firm support each time you have treatment. The cushion is called a vac pac.

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.

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. 

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.