Radiation Therapy Simulation

What is a radiation therapy simulation?

If you have cancer and are going to receive radiation therapy, you will probably have a radiation therapy simulation before your first treatment. A simulation session is a meeting between you, the radiation oncologist, and other members of the radiation team. During this meeting, you and the radiation team plan where and how to use the radiation to destroy your cancer cells.

Radiation therapy uses high-energy radiation (X-rays) to shrink or destroy a tumor. It can cure cancer or help you feel better by making the tumor smaller.

Some alternatives to radiation therapy are:

• having chemotherapy (using medicine to destroy the cancer)
• removing the cancer by surgery
• choosing not to have treatment.

You should ask your healthcare provider about these choices.

How should I prepare for the simulation?

Follow the instructions provided by your healthcare provider. You may have a CT scan or PET scan before the session to find the exact spot the cancer is in.

What happens during the simulation?

During the session you will meet your treatment team, will see the equipment they use, and can ask questions.

A medical physicist, or dosimetrist, will work with the radiation oncologist to find the best way to aim the radiation at your cancer. You will lie on a special type of X-ray table. The radiation therapist:

• Will mark your body with ink to highlight the area to be treated.
• May also use a low-energy laser to mark the area. (You will not feel any burning or pain from the laser.)
• Will record measurements using prominent bones, such as your hipbone, as reference points.
• Will take several X-rays to be sure the radiation will be aimed where it will work best.
• Will repeat the aiming process for different angles if you are going to receive radiation from more than one angle.

The treatment team may need to make shields or devices to focus the radiation on your tumor. The shields are attached to the radiation machine. They will help protect your healthy tissue from radiation.

What happens after the simulation?

The practice session is a good time for you to ask questions about the side effects of the planned radiation therapy. You can find out what to expect and what you should not have to worry about.

You should ask:

• How long will each radiation treatment last? How often will I have treatments? How many weeks will I have treatments?
• What side effects might I have? When do they usually start?
• Will I feel well enough after treatments to drive myself home?
• What should I expect if I am having chemotherapy or surgery, or both, together with radiation therapy?
• What do I need to do to prepare for these treatments?
• Are there recommendations for my diet? How much rest will I need?
• What should I expect after the treatments are over?
• What should I expect if I choose not to have this treatment?

After the session you may go home. You should not wash off the ink marks. The therapist will need them for the radiation sessions.

Soon after the radiation simulation, you will begin your radiation treatments. During the course of this care you may have another practice session to plan treatment for a smaller area.