Planning for Radiation

Together with the oncologist, the St Stephen radiotherapy team will carefully work out how much radiation you need to treat cancer and
exactly where you need it.

As cancer cells may sometimes spread into the tissues close to a tumour, our radiotherapy specialist will decide on the exact area to be treated around cancer. They will also make allowances for possible movement of a tumour during treatment due to breathing or normal movement of body organs.

• The radiotherapy planning makes sure that cancer gets the prescribed dose of radiation while normal body tissues get as little as possible.
• The area of your body exposed to radiation is called the radiotherapy field.
• Some normal tissue immediately around a tumour will be exposed to the same dose but your doctors aim to keep this as low as possible to reduce the risk of side effects.

To plan the treatment your doctor will take into account :

• your type of cancer
• the position of cancer in the body
• the size of the cancer
• whether it is close to structures that are sensitive to radiation
• how far the radiation needs to travel into the body
• your general health and medical history

More than one planning session may be needed as it depends on the size and position of a tumour.

For your first treatment, you will be given an appointment which could vary from 30 to 60 minutes. The planning department will check and verify all of the plan parameters before you start treatment. At the treatment unit, you will now also meet the radiotherapists responsible for your treatment. In the treatment room, you are set up in the same position you were scanned in. A set of verification x-ray images will then be taken. These images are called “portal images” or “verification films” and form part of the “virtual simulation” process. They are used to compare the computer planned position to the actual treatment position and need to be approved by the oncologist before treatment commences. In some cases, you will not be treated on the first day. The radiotherapists will only take the position images. Treatment will then start on your second visit to St Stephen’s.

On your daily treatment sessions, you will be set up in the treatment position on the treatment couch and your reference marks checked. A set of x- ray images (portal films) will be taken regularly to verify the treatment area. Once the radiotherapists are satisfied that your treatment position is correct they will leave the room and operate the machine from the control room. They will be able to monitor you on closed circuit TV screens and speak to you if necessary via an intercom. Radiotherapy is NOT PAINFUL and you won’t feel anything during treatment. After your second treatment, you will feel at ease, allowing the machine to do the work, aiding you on the road to recovery.