Simulation

Simulation helps your radiation oncologist determine your treatment portal -- the exact place on your body through which the treatments will be aimed. Many cancers are located deep within the body. Your radiation oncologist must find the exact location of your cancer in relation to your body surface and surrounding normal tissues. This allows him or her to focus treatment on cancerous cells while sparing normal ones from radiation damage. In addition to examining you and reviewing your medical records, the physician may request CT scans, MRI studies, ultrasound exams or nuclear medicine tests to help him or her map out your treatment portal.

During the simulation process, you will be asked to lie very still on a table while the dosimetrist uses a special X-ray machine called a treatment simulator. Simulation can take anywhere from half an hour to two hours to complete.

Once your treatment portal is determined, the skin over the area is marked with tiny dots of colored ink. This allows the radiation therapist to position you precisely on the treatment machine each day. Some patients have more than one treatment portal, so the cancer can be attacked from several different directions.

Using a Block

Sometimes X-rays taken during the simulation process are used to make special blocks to shape the radiation beam. Molds are cut by tracing an X-ray which shows the shape of your treatment field. Then the molds are filled with a molten lead alloy. Once the allow cools, the blocks are ready for use. They will be marked with your name and kept in the treatment room.

Treatment Planning

Using the Radiation Center's treatment planning computer, your radiation oncologist and the dosimetrist will compute how much radiation you will need, how it will be delivered, the directions from which the rays will be aimed, and how many treatments you should have.

Radiation therapy is given in doses called centi-Gray. The actual number of treatments you will receive depends on the total dose you need, the size and location of your cancer, the type of tumor and your general health. Radiation is given a little at a time, rather than all at once, to protect healthy body tissue. Treatments are usually received five days a week for a period of several weeks. Weekend breaks give normal cells a chance to recover.

Treatment with a Linear Accelerator

The linear accelerator is the machine which actually delivers the radiation treatment. It produces ionizing radiation which destroys cancer cells.

Before each treatment, you may be asked to change into a hospital gown. Then you will be taken to the treatment room where the radiation therapist will carefully position you on the table, using the marks on your skin to locate the treatment area. During your treatments, you must lie very still to make sure the radiation hits the right spot each time.

The therapist will leave the treatment room before turning on the linear accelerator. He or she will be able to see you and hear you on a television monitor recessed in the control area outside the treatment room. Treatments themselves last less than a minute. You won't be able to feel the radiation while you are receiving it.

Follow up

During the course of your treatment, you radiation oncologist will watch you carefully to see how well you are tolerating the radiation treatment. Some patients need additional X-rays, CT scans or blood work so the doctor can see the tumor's response to therapy.

For more information about the services provided at the Radiation Center, call (502) 897-8163. The Radiation Center is located in the 4003 Building across the street from the hospital.

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