Simulation is simply the process of conducting a radiation-free “run-through” of your treatment, as well as measuring and “mapping” the treatment field. The chief radiation therapist will ask you to lie very still on an examination table. Using special x-ray equipment, called a simulator, the radiation therapist will define the exact treatment area on your body. Sometimes, there will be more than one field, depending upon the location of your cancer.

The field is “mapped out” on your body using semi-permanent ink. Permanent tattoos, the size of a pinhead, may also be applied to define the treatment area. These markings enable the radiation team to correctly position you, so that the radiation is precisely administered every time.

It is important that you are very gentle in washing the area of treatment, in order to prevent removing the markings.

In addition to the markings, immobilization devices may also be made. These devices conform to your body and inhibit you from shifting around during treatment.

Not as scary as they sound, some immobilization devices are simply blue vinyl bags filled with little Styrofoam balls, much like a beanbag. While the bag is positioned under you, the air is drawn out of the bag, forcing the “balls” to compact together and mold against your body.

For those patients being treated for head or neck cancer, a “mask” may be made to keep your head from shifting. This painless process involves molding slightly warmed mesh plastic around your head. In addition to immobilization, this mask also provides the therapist with a surface, other than your skin, to mark or define your treatment area.

Once the simulation process is completed, your radiation oncologist will meet with the radiation physicist and dosimetrist to determine the plan of treatment. The amount of dosage, type of delivery and number of treatments will be based upon the nature and location of your cancer, as well as the results from your x-rays, scans, pathology, labwork, medical history and any other therapies or treatments you have already received.
When this is completed, you will be ready to begin treatment.