Simulation is an important process where your radiation treatment position will be established and images of your body will be obtained for treatment planning. Most patients have a CT scan (low radiation dose protocol, no contrast in the bloodstream in most cases) performed in our department as part of this process. The information from the simulation process is used to create a unique three-dimensional treatment plan based on your specific anatomy and treatment location. Small tattoos are placed on the skin at this time to ensure reproducible and accurate positioning on a daily basis for radiation treatment.