What you can expect

Stereotactic radiosurgery is usually an outpatient procedure, but the entire process will take most of a day. You may be advised to have a family member or friend who can be with you during the day and who can take you home.

You may have a tube that delivers fluids to your blood stream (intravenous, or IV, line) to keep you hydrated during the day if you are not allowed to eat or drink during the procedure. A needle at the end of the IV is placed in a vein, most likely in your arm.

Before the procedure

The steps immediately prior to treatment may vary depending on the location of your treatment area and the type of equipment being used to deliver the radiation.

Preparation for Gamma Knife and LINAC stereotactic radiosurgery of the brain is very similar (except for the first step — a head frame is not needed for LINAC stereotactic radiosurgery) and involves three steps:

1. Head frame placement. Before the procedure begins, you'll have a lightweight frame attached to your head with four pins. This frame will stabilize your head during the radiation treatment and serve as a point of reference for focusing the beams of radiation. Some types of brain radiosurgery may not require head frame placement.

   If a head frame is required, you'll receive numbing shots in the four places on your scalp where the pins will be inserted — two points on your forehead and two at the back of your head. Your hair will not be shaved, and you may be given a special shampoo to cleanse your scalp and help the frame stay in place.

   You don't need a head frame with LINAC stereotactic radiosurgery of the brain. The radiosurgery typically can be delivered with a soft plastic mask that forms to your face. The advantage of this approach is it facilitates multiple (three to five) treatments and avoids the uncomfortableness of frame placement.

2. Imaging. After the head frame is attached, you'll undergo imaging scans of your brain that show the location of the tumor or other abnormality in relation to the head frame. The type of scan used depends on the condition being treated:

   • Tumors. Imaging for tumors may include computerized tomography (CT) scan or magnetic resonance imaging (MRI). In a CT scan, a series of X-rays create a detailed image of your brain. In an MRI scan, a magnetic field and radio waves create detailed images of your brain.

     Doctors may inject a dye into a blood vessel to view the blood vessels in your brain and highlight blood circulation. In some cases, you may have an MRI scan and a CT scan.

   • Arteriovenous malformations (AVMs). Imaging for brain AVMs may include CT scans, MRI scans, cerebral angiograms or some combination of these tests.

     In a cerebral angiogram, a doctor inserts a small tube in a blood vessel in your groin and threads it to the brain using X-ray imaging. A doctor injects dye through the blood vessels to make them visible on X-rays. Your doctor may inject a dye into a blood vessel during CT or MRI scans to view the blood vessels and highlight blood circulation.

   • Trigeminal neuralgia. An MRI or CT scan is used to create images of nerve fibers to select a target area for treating trigeminal neuralgia.

3. Dose planning. The results of the brain scans are fed into a computerized planning system that enables the radiosurgery team to plan the appropriate areas to treat, dosages of radiation and how to focus the radiation beams to treat the areas.

   This planning process may take an hour or two. During that time, you can relax in another room, but the frame must remain attached to your head. If you are doing LINAC stereotactic radiosurgery of the brain, typically you would be sent home during the planning process and treatment would be delivered a few days later.

Preparation for stereotactic radiosurgery or radiotherapy for other parts of the body also involves several steps, including:

1. Marking. Some SRS technologies require the placement of a fiducial marker in or near the tumor in certain cases. This procedure is usually done as an outpatient procedure prior to SRS treatment. But this step is not needed for most CT-guided technologies.

2. Simulation. A radiation oncologist will conduct a simulation to determine the best placement of your body to align it with the radiation beams. Your body will be held very tightly and still by an immobilization device. Tell your doctor if you have claustrophobia.

   After you are immobilized, imaging scans will be taken, and you'll likely be sent home prior to the next stage.

3. Planning. Using the imaging scans and specialized software, your treatment team will determine the best combination of radiation beams to target your tumor or other abnormality.

During the procedure

Children are often anesthetized for the imaging tests and during the radiosurgery. Adults are usually awake, but you may be given a mild sedative to help you relax.

If you are using a Gamma Knife machine, you'll lie on a bed that slides into the machine, and your head frame will be attached securely to the bed frame. The machine does not move during treatment; instead, the bed moves within the machine. The procedure may take less than an hour to about four hours, depending on the size and shape of the target. If treating with LINAC stereotactic radiosurgery of the brain the treatment will be quicker.

Unlike the Gamma Knife, the LINAC machine moves and rotates around the target during treatment to deliver radiation beams from different angles. The treatment takes less than an hour.

During the procedure:

• You won't feel the radiation.
• You'll be able to talk with the doctors via a microphone.

After the procedure

After the procedure, you can expect the following:

• The head frame, if used, will be removed. You may have minor bleeding or tenderness at the pin sites.
• If you experience headache, nausea or vomiting after the procedure, you'll receive appropriate medications.
• You'll be able to eat and drink after the procedure.