CT Simulation

To be most effective, the radiation beam must be aimed precisely at the exact location each time that treatments are given. The process of measuring anatomy and marking the skin so that we can guide the radiation to the exact location prescribed by your Radiation Oncologist is called “simulation.”

CT simulation is the most accurate process available to localize, define, and reconstruct, in 3-D, a patient’s anatomy. This process identifies the tumor along with the normal tissue surrounding it, allowing the radiation oncologist to design a treatment plan unique to each patient’s anatomy.

The first step in the simulation procedure is determining the exact position that you will be treated in. The radiation therapist and radiation oncologist will work together to establish the exact treatment position desired for treatment. This position will be reproduced daily during radiation treatments. The patient must be able to maintain this position for 15-30 minutes daily.

During this appointment the patient will be given tattoos to aid in daily treatment positioning. These tattoos are permanent, but small enough so as not to be noticeable to anyone but the radiation therapist. Tattoos are achieved by inserting a small amount of ink under the skin with the tip of a needle. The resulting tattoos are the size of a small freckle.

The radiation oncologist and dosimetrist will then utilize the CT and/or other studies obtained to plan your radiation therapy treatments on a specialized treatment-planning computer.