Planning your treatment
The process of planning external beam radiation treatment is complex and might take several weeks to complete. It is one of the most important parts of your radiation treatment. After your planning session, check with staff on how long it will be before your treatment starts. A treatment plan will be designed just for you. It will give the required dose of radiation to the cancer but will spare as much normal tissue as possible. This will help reduce the side effects. If you are having treatment to your pelvis, you might be sent instructions on how to prepare your bladder and bowel for this treatment.
The first part of treatment planning is called simulation, sometimes referred to as a marking up session.
Image: Special supports and pillows might be used to help you keep in the same position for each treatment. A CT scanner for simulation can be seen in the background.
Simulation and planning
Before you start a course of radiation you will require at least one visit to the cancer centre to work out the exact position you will lie in during your treatment. This is known as simulation. A simulator – a machine similar to a treatment machine or a CT scanner – is used for this.
During planning, the treatment team considers many factors,
including:
- what type of radiation to use
- the size and shape of the radiation field
- patient position as well as machine positioning
- how much radiation is to be delivered for each treatment
- how many beams of radiation.
This is all done on computers using the information from simulation, a CT scan, and other tests you have had.
“It’s like an X-ray machine. No worries. You’ve got a comfortable room, music going, then it’s over.” Milly
This whole process of simulation can take 30-60 minutes and is a much longer process than each individual treatment.
It is important that you lie still in the same position when you have your treatment. You might have an ‘immobilisation device’ to help you keep still. This can range from special supports to a face mask made of plastic for people requiring treatment to the head and neck area.
“When they made the mask they were really good about talking to me and telling me what they were doing. They said that it would feel like a pressure, and how long it would take.” Melinda
The machine is set to treat exactly what is to be treated with a ‘safety margin’. Once the position of the beam is worked out, your skin or the mask will be marked. This may require a tattoo which is a permanent marking, but occasionally can be removed later. It can be helpful to have a family member or friend with you during simulation and planning.
Image: Here a radiation therapist is showing the patient the plastic mask, which will help her stay in position. The positioning marks are drawn on the mask, not on the face.