by de la Rocha K


Stereotactic radiosurgery (SRS) is a way to treat brain disorders. It uses highly focused beams of radiation to target specific areas of the brain. It can also be used on other parts of the body such as the spine. The beams of radiation destroy the tissue that a neurosurgeon would have removed during an operation.

Reasons for Procedure

SRS is used to:

  • Stop cancerous and noncancerous tumor growth
  • Shrink cancerous and noncancerous tumors
  • Close off arteriovenous malformations (AVMs)—abnormal blood vessels that disrupt blood flow to the brain
  • Treat disorders such as:
Brain Tumor
Brain Tumor
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Possible Complications

Problems from the procedure are rare, but all procedures have some risk. Your doctor will review potential problems, like:

  • Headache
  • Temporary swelling at the treatment site, which may be associated with worsening of symptoms
  • Swelling, numbness, bleeding, or tingling around the sites where the head frame rests on the head
  • Skin irritation
  • Nausea
  • Seizures
  • Patchy hair loss from the radiation
  • Permanent injury to the location in the brain being treated

Rare complications may include:

  • Vision loss
  • Deafness
  • Bleeding
  • Nerve problems

Before your procedure, talk to your doctor about ways to manage factors that may increase your risk of complications such as:

Other factors that may increase the risk of complications include:

  • Prior surgeries
  • Prior radiation treatments

What to Expect

Prior to Procedure

You will receive treatment from your doctor and a team of others who specialize in radiation. Your doctor may do the following:

  • Perform a neurological exam to see how well your nervous system is functioning
  • Review your x-rays , CT scans , MRI scans , or other diagnostic test results
  • Order additional tests if necessary

Your doctor may ask if you:

  • Take medication or insulin to control diabetes
  • Are allergic to IV contrast material—an injected substance that can make a tumor or other abnormality easier to see
  • Are allergic to iodine or shellfish—iodine is present in both shellfish and contrast material
  • Have a pacemaker or any other medical device implanted in your body
  • Have eye or ear implants
  • Have had any previous surgeries
  • Have ever had trauma to the skull
  • Suffer from claustrophobia

Leading up to your procedure:

  • Review your regular medications with your doctor. You may be asked to stop taking some medications before the procedure.
  • Arrange for someone to:
    • Drive you to the treatment facility
    • Drive you home after
    • Stay with you during treatment
    • Stay with you the following night
  • If advised by your doctor, use a special shampoo.

The day before your procedure:

  • Do not use any hair creams or hair spray.
  • Do not eat or drink anything after midnight unless told otherwise by your doctor.

The day of your procedure:

  • Bring your regular prescription medications with you to the hospital.
  • Do not wear jewelry, make-up, nail polish, a wig, or a hairpiece.
  • Remove any contact lenses, eyeglasses, or dentures.
  • An IV line will deliver contrast material, medications, and fluids.


  • You will receive a mild sedative to help you relax.
  • A local anesthetic may be injected to numb your scalp.

Description of Procedure

There are a few types of SRS:

Cobalt-60-based Treatment

The procedure will be done using beams of highly focused gamma rays. It is used to treat smaller brain tumors and functional brain disorders.

There are 4 phases to this treatment:

  • Head frame placement —Local anesthesia will be injected into the front and back of your head to numb your scalp. A box-shaped, aluminum frame will be attached to your skull with special pins. This will keep your head from moving during treatment.
  • Imaging —You will have a CT scan and/or MRI to locate the tumor. If you are being treated for an AVM, you may have a test called an angiography to locate the abnormal veins.
  • Computerized dose planning —You will relax for about an hour while your doctors plan your treatment. When they are finished, you will lie down on a special couch. Your doctor will talk to you about the number of treatments you will receive and how long they will take. Your head frame will then be attached to a helmet full of small holes. Each hole will allow a single ray of radiation to target a specific part of your brain.
  • Radiation delivery —The doctors and nurses will leave the room. Your couch will move into the treatment area. You might hear a click as the helmet locks into place. Your doctor will be able to see and hear you during the entire procedure. You will be able to talk to your doctor. You will remain still during the procedure and so will the machinery around you. You will not be able to see, feel, or hear the treatment. When treatment is complete, the couch will move back to its original position.
Linear accelerator (LINAC)-based Treatment

This treatment uses one large, powerful radiation beam. It is used to treat small and large brain tumors. You will go through the same phases listed above. During radiation delivery, part of the machine will move around you. The treatment couch will also be moved. Some newer systems can also deliver radiation to tumors of the spinal cord.

Robotic Radiosurgery System

This treatment is given using a small linear accelerator that is on top of a robotic arm. It is used to treat tumors and injuries of the brain and spine. No head frame is used.

There are 3 phases to this treatment:

  • Set-up —If you are being treated for a brain tumor, a special mask will be made to fit your head. No pins are needed to keep it in place. You will be given a CT scan, and possibly an MRI, with the mask in place. If you are being treated for a spinal tumor, a customized foam body cradle will be made instead of a mask. You will most likely have some small metal markers called fiducials implanted near the tumor. The markers will help guide the radiation beams during treatment. The fiducials are implanted during a short outpatient procedure. After they are in place, you will be given a CT scan.
  • Treatment planning —You may be allowed to go home while the doctors finalize your treatment plan. Actual treatment may take place that same day or several days after the set-up phase.
  • Treatment delivery —You will be fitted with your mask or body cradle and then lie down on the treatment table. X-rays will be taken before the treatment starts. After treatment begins, the robotic arm will move around you and administer radiation beams from many different angles. Sometimes the arm will stop and more x-rays will be taken.

After Procedure

If your treatment required a head frame:

  • The head frame and IV line will be removed.
  • Your head will be wrapped in gauze or small bandages will be placed at the pin sites.

How Long Will It Take?

  • Radiation delivery can take up to 2 hours for cobalt-60-based treatment and LINAC-based treatments. Robotic radiosurgery treatments can take up to 3 hours.
  • The total procedure usually takes 2-4 hours.

Will It Hurt?

  • Anesthesia prevents pain at the pin sites if a head frame is used during treatment.
  • You will feel some pressure as the head frame is attached.
  • The treatment itself causes no pain.
  • You may experience headaches or nausea a few hours after treatment. You will be given medication to relieve any discomfort.

Post-procedure Care

During your stay the hospital staff will take steps to reduce your chance of infection such as:

  • Washing their hands
  • Wearing gloves or masks
  • Keeping your incisions covered

There are also steps you can take to reduce your chances of infection such as:

  • Washing your hands often and reminding visitors and healthcare providers to do the same
  • Reminding your healthcare providers to wear gloves or masks
  • Not allowing others to touch your incisions

SRS works over time. It may take several months to several years to see results.

  • About one month after your procedure, your doctor will check your pin sites and do a neurological exam.
  • CT scans or MRIs will likely be done sometime after the procedure to determine if treatment was effective. The number of scans and how often you get them may vary.
  • If you were treated for an AVM, you will have a test called a cerebral angiogram 2 to 3 years after treatment. The test will determine if treatment was successful.
  • In many cases, SRS treatments can be repeated, if necessary.

Call Your Doctor

Call your doctor if any of these occur:

  • Signs of infection, including fever and chills
  • Redness, swelling, increasing pain, excessive bleeding, or any discharge from the pin sites
  • Pain that you cannot control with the medications you were given
  • Persistent nausea or vomiting
  • Cough, shortness of breath, irregular heart beat, or chest pain
  • Severe headache
  • Weakness, numbness, or loss of balance
  • Vision problems
  • Seizures
  • Any new or unexpected symptoms

If you think you have an emergency, call for emergency medical services right away.


American Association of Neurological Surgeons 

Radiology Info—Radiological Society of North America 


Canadian Association of Radiologists 

Health Canada 


Frequently asked questions. International Radiosurgical Association website. Available at: Accessed January 28, 2021.

Linear accelerator. Radiology Info—Radiological Society of North America website. Available at: Accessed January 28, 2021.

Stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). Radiology Info—Radiological Society of North America website. Available at: Accessed January 28, 2021.

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