GAMMA KNIFE RADIOSURGERY noninvasive brain and neck procedures

A Revolution in Care.

Gamma Knife®

Radiosurgery Using Sophisticated Technology

Gamma Knife Radiosurgery in Miami

What is Gamma Knife?

Gamma Knife is a pain-free, noninvasive, stereotactic radiation therapy that uses 192 intersecting gamma rays of radiation to treat brain cancer, brain tumors, trigeminal neuralgia, glioblastoma, meningioma, AVM, and other neurological disorders. 

The Gamma Knife is designed explicitly for cervical spine and brain conditions. During the procedure, these areas are isolated from movement to ensure the precise delivery of the gamma rays to the target area, avoiding healthy surrounding tissue.

Although Gamma “Knife” evokes the image of an invasive surgical procedure, this is a common misconception. Radiosurgery does not require an incision into the skin with a scalpel nor the opening of the skull.

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Patient treated with Gamma Knife for brain tumor
surgery on the brain
Noninvasive Brain and Neck Procedures
Trigeminal Neuralgia Treatment

5 Simple Steps to a Gamma Knife Procedure

The steps of a Gamma Knife procedure are simple. If you would like a more in-depth explanation read the before, during, and after Gamma Knife radiosurgery questions to follow. To undergo the procedure, you are simply:

Administered an IV, mild sedation, and contrast dye for imaging studies.

Crowned with a rectangular metal frame that stabilizes you during the imaging process and the procedure, using four pins. Don’t fear, you will be asleep due to the sedation.

Examined using imaging studies (MRI, CT scan, and/or Angiography) to map the malformation and develop a treatment plan.

Secured on a sliding table that enters and exits the Gamma Knife machine. The procedure is silent, pain-free, and lasts anywhere between 15 minutes to under two hours.

Sent home once the frame is removed, after-care is provided to the wound sites, lunch is provided, prescriptions are administered, and a follow-up appointment is scheduled.

Often, patients finish treatment in disbelief that they underwent radiosurgery.

Don’t be fooled from this simplified description, the Gamma Knife machine is a sophisticated technology that requires a whole team of professionals to operate. The Gamma Knife team is composed of physicians, physicists, neuroradiologists, physician assistants, nurses, and radiation oncologists.

Gamma Knife® Radiosurgery

Designed For Noninvasive Brain and Neck Procedures

The extreme precision of the Gamma Knife Perfexion makes it a safe and effective system for treating neurological disorders.

The Gamma Knife Treats:

  • Trigeminal Neuralgia
  • Glioblastoma
  • Brain Tumor
  • Meningioma
  • AVM (Arteriovenous malformation)
  • Brain Cancer
  • DIPG (Diffuse Intrinsic Pontine Glioma)
  • Pituitary Tumor
  • Migraine Headache
  • Astrocytoma
  • Craniopharyngiomas
  • Neck Cancer
  • Vestibular Schwannomas
  • Hemangioblastomas
  • Brain Metastases
  • Hemangiopericytomas
  • Cavernous Angiomas



Pituitary Adenoma

What are the Advantages of Gamma Knife Radiosurgery?


Gamma Knife does not require general anesthesia, nor involve the risks associated with open surgery, such as hemorrhage, infection, CSF leaks or other morbidities.

Increased Accuracy

A dedicated neurosurgical tool that is accurate to 0.15 mm, Gamma Knife is specially designed to reach deep-seated targets in the brain, cervical spine, head, and neck.

Reduced Side Effects

Gamma Knife does not cause cognitive deficits, hair loss, nausea, fatigue or other side effects associated with conventional radiation therapy.

Versatile Treatment Options

Gamma Knife allows for different beam sizes in unlimited directions, providing the ability to reach multiple isocenters in a single session. No other modality offers this level of versatility.

Rapid Recovery

Gamma Knife surgery is painless and takes only a few hours. Patients return home the same day and resume normal activities almost immediately.

Single Session

Gamma Knife is a noninvasive method that is always performed in a single session and does not require treatment planning prior to procedure day.

Most Established Modality

Gamma Knife has been clinically documented in more than 2,500 peer-reviewed papers and in every major neurological journal.

Dedicated Neurosurgical Tool

Gamma Knife is the only system designed specifically to treat the brain, head and neck.


How does Gamma Knife work?

The Gamma Knife Perfexion uses 192 Cobalt 60 sources which continuously produce high energy gamma rays used for treatment.  Similar to the way a lampshade encircles a light bulb the 192 Cobalt 60 sources encircle the Gamma Knife Perfexion center-point known as the isocenter. 

Sources are fixed within eight independently movable plates, referred to as sectors, each containing an array of 24. When treatment begins, each sector, if used, is positioned over 24 corresponding beam channels, which all converge at the isocenter. Different beam diameters are available for use including 4mm, 8mm or 16mm. The choice of beam size depends on the size of the target (or portion of target) positioned at the isocenter.

The treatment beams pass right through the patient’s head, depositing a small amount of energy along the way. The beams are not aimed at the treatment target inside the brain; instead, the treatment couch is moved so that the treatment target position coincides with the isocenter. The treatment target is hit by all the treatment beams being used while the surrounding healthy brain is affected by zero or one beam. By the end of a Gamma Knife treatment, each portion of each target will have been positioned at the isocenter, the one place where all treatment beams converge.

The Gamma Knife technology was reportedly described by its inventor, neurosurgeon Lars Leksell, as being “so simple even a neurosurgeon can use it.” Being a physicist, I think that’s funny. From my point of view, the Gamma Knife requires minimal attention due to its simplicity which translates into unmatched reliability in treatment delivery.


How do Gamma rays kill cancer cells?

As Cobalt-60 decays, it emits gamma and beta rays in all directions. While beta rays are absorbed quickly into the tissue, gamma rays are absorbed slower. This lower rate of absorption allows the gamma rays to travel through the body without severely damaging (also called ionizing) the cells on the ray’s path.

Ionizing radiation is a term used to describe the process where radiation breaks down the structures in the nucleus and kills the cell. It does this by creating an imbalance of electrons that inhibit cancerous cells from recovering. The lower ionization (or damage) to the cells on the path of the ray gives the healthy cells a chance to repair themselves. 

Only at the point where the 192 gamma rays converge (the isocenter) is a potent dose of radiation delivered. This is because, at that intersection point, the ionization rate is much higher than the surrounding areas.

What are the risks or complications of Gamma Knife Radiosurgery?

Some patients may experience a mild headache or minor swelling at the pin sites, but most report no discomfort.

Other side effects could include: 

  • Fatigue
  • Nausea
  • Headache
  • Dizziness
  • Impaired balance (Ataxia)
  • Hearing problems

Gamma Knife vs Other Treatment Modalities

Gamma Knife versus Cyberknife, Novalis, Trilogy, and Radiation Therapy

AdvantagesGamma KnifeCyberknife - Novalis - TrilogyRadiation Therapy
Increased Accuracy
Reduced Side Effects
Versatile Treatment Options
Rapid Recovery
Single Session
Most Established Modality
Dedicated Neurosurgical Tool

Gamma Knife versus Whole Brain Radiation Therapy (WBRT)

WBRT is a form of external beam radiation therapy that uses a linear accelerator to treat the entire brain with a low dose of radiation. It is considered traditional radiation therapy and is performed on an outpatient basis, 5 days a week for two weeks.

Gamma Knife is a form of stereotactic radiosurgery (SRS) that precisely targets a neurological disorder with a high dose of Cobalt-60 radiation. It is also performed on an outpatient basis and generally requires a single treatment.

Increasingly, Gamma Knife is replacing WBRT due to concerns regarding the adverse effects of WBRT on cognitive functions 6 months after treatment and suboptimal tumor control.

When to consider Gamma Knife:

  • As a monotherapy (on its own) if you have less than 5 metastases and want to avoid the adverse effects and toxicity of WBRT1
  • If you have brain metastases that are resistant to radiation such as renal cell carcinoma, melanoma, and sarcoma1
  • As a salvage therapy after WBRT failure1
  • As a boost after WBRT if you have less than 10 metastases1

How are Gamma Knife and WBRT different?

  • Precision
    • Gamma Knife is a targeted treatment approach that minimizes radiation to healthy brain tissue while WBRT treats the entire brain.
  • Radiation dose
    • Gamma Knife provides a higher, quicker, and precise dose of radiation with a steep fall off, while WBRT involves a lower dose of radiation over a more extended period.
  • Number of treatments
    • Both treatments can be performed on an outpatient basis. However, Gamma Knife generally requires a single treatment while WBRT requires 5 treatments over two weeks. 
  • Long term effects on cognitive functions
    • Studies demonstrate that patients undergoing WBRT have late delayed (+ 6 months) radiation-induced brain injuries affecting their cognitive functions (memory, attention, and concentration)2,3

SRS vs. WBRT + SRS for patients with 1 to 3 brain metastases4

 SRS plus WBRTSRS Alone
Cognitive deterioration at 3 months91.7% of patients63.5% of patients
Cognitive deterioration at 12 months for long-term survivors94.4% of patients60% of patients
Quality of life at 3 monthsLowerHigher
Time to intracranial failureLongerShorter
Median overall survival7.4 months10.4 months

Gamma Knife and other forms of stereotactic radiosurgery (SRS) may be used as an alternative to or in conjunction with WBRT. 
Developing a treatment plan is complex and unique to each patient. It involves a variety of factors, including:

  • Previous treatments, number of attempts, and the success or failure of those attempts
  • Number of tumors
  • If you have a recurrence of brain tumors
  • If you have radioresistant brain tumors
  • Life expectancy
  • If the metastases is isolated within the brain or it is also outside the brain


1. The Role of Surgery, Radiosurgery and Whole Brain Radiation Therapy in the Management of Patients with Metastatic Brain Tumors -
2. A randomised trial to compare cognitive outcome after gamma knife radiosurgery versus whole brain radiation therapy in patients with multiple brain metastases: research protocol CAR-study B -
3. Neurocognitive functioning and health-related quality of life in patients treated with stereotactic radiotherapy for brain metastases: a prospective study -
4. Effect of Radiosurgery Alone vs Radiosurgery With Whole Brain Radiation Therapy on Cognitive Function in Patients With 1 to 3 Brain Metastases -

Gamma knife versus open brain surgery

Gamma Knife is a safe, efficient, and cost-effective alternative to open brain surgery (also called resection). It does not require general anesthesia nor involve the risks associated with open surgery such as hemorrhage, infection, CSF leaks, or other morbidities.

Multiple studies demonstrate that the overall cost to the patient and provider is significantly lower for Gamma Knife than open surgery. For example, the cost to treat patients with Gamma Knife for conditions such as brain metastases, acoustic neuromas, and AVM is about 50% less than patients treated with open surgery.1

With Gamma Knife, patients can expect:

  • Quicker recoveries
  • Less time off of work
  • Shorter or no hospital stay
  • Reduced utilization of hospital resources
  • Lower complication rates and mortality rates.2
Gamma KnifeOpen Surgery
Hospital Length of Stay (LOS)2.2 days (At our center it is extremely rare for patients to be hospitalized. Gamma Knife is performed on an outpatient basis)18 days (around 5 days in the ICU and 13 days in the ward)
Is Intensive Care Required?NoYes
Loss of workdays8 days (At our center patients generally resume normal activities the next day)160 days
Complication Rates3.8%31.2%
Mortality RateNo mortality5.3%
Can treat conditions that are deep within the brain or difficult to reachYesMore difficult, if not impossible


1. A cost comparative study of Gamma Knife radiosurgery versus open surgery for intracranial pathology. -
2. Socioeconomic Costs of Open Surgery and Gamma Knife Radiosurgery for Benign Cranial Base Tumors -

Before, During, and After the Gamma Knife Procedure

Before treatment, Dr. Wolf and the Gamma Knife team will discuss the procedure with you, answer your questions, and share details about what to expect. 

  • Leave valuables at home, such as jewelry, watches, necklaces, etc.
  • Stop drinking/ eating the midnight before the procedure
    • Small sips of water with medications are ok
  • Wear clothing that is comfortable and easy to change in and out of as you will be provided a gown to wear from the placement to the removal of the metal frame.  
  • Generally, it is ok to take your regular medications such as antihypertensives. However, provide your doctor with a list of medications you are taking so they can instruct you accordingly. You will be provided a mild anesthetic and other antibiotics that might react with certain medications.
    • Some medications that are not fine to take before Gamma Knife surgery include:
      • Bloods thinners (24 hours before the procedures)
  • If you have any allergies, let your doctor know before the procedure. This includes:
    • Iodine-based substances such as contrast agents or dyes which are used during imaging studies
    • Latex products such as gloves
  • You can shower on the morning of your procedure. You may be provided bathing products to use, such as shampoo. If not, you can use your products. Avoid using hair products in the morning, such as sprays and gels.
  • Come with a friend or family member that will stay in the patient waiting area during the procedure and will drive you home afterward.
    • Tell your ride to bring a book, laptop, or other entertainment devices to stay busy during your procedure.

On the day of the procedure, you will arrive at the center in the morning, walk straight past the elevators into the waiting area on the first floor. Generally, a nurse will be waiting for you, but if not, ring the doorbell. Try to arrive at least 15 minutes before your appointment time to ensure you are on time and have ample time to park.

A nurse will come to greet you and escort you to the prep area, which is a large room with several beds, privacy curtains, and a nursing bridge station. 

There, you are given a gown to change into and a personal belongings bag to store your clothes, keys, phone, and other items. Your belongings will be placed on a shelf near your bed. Don’t worry, your area will not be used by anyone else during your procedure. However, as previously stated, please leave valuables at home, such as jewelry.

In the prep area, the nurse will perform a quick personal history, ask you the last time you ate or drank, give you an IV to sedate you, and administer antibiotics.

When you are asleep, the physician and the physician assistant will attach a lightweight stereotactic head frame. The structure weighs less than two pounds and is adjusted to your head size and dimensions. The physician will inject lidocaine (local anesthesia) at the four sites the pins are placed. 

With the frame in place, the team will place a coordinate box on the frame to provide reference points on the images for the treatment plan. Down the hall, you will undergo advanced imaging studies — such as MRI, CT scan or angiography — to precisely determine the size, shape, and location of the brain tumor or glioblastoma, or to locate the trigeminal nerve.

When the imaging studies conclude, you will be brought back to the prep area. Generally, by this time you will reawaken. Initially, you may feel pressure around your head, but this pressure will resolve within several minutes.

While you relax, the Gamma Knife team will develop your treatment plan using the imaging results and state-of-the-art Gamma Knife 3-D planning software. This can take anywhere between 30 minutes to an hour. Your treatment will be completely individualized to address your specific neurological disorder. When completed, the nurse will take you to the Gamma Knife room to begin the procedure.

To begin treatment, you will lie down on the Gamma Knife treatment table, and your surgical team will attach the head frame to the Gamma Knife machine. When the procedure begins, the table will move into the dome section of the unit. Gamma Knife’s robotic Automatic Positioning System will move you into the correct position for the delivery of multiple rays. Using three-beam sizes (4 mm, 8 mm, or 16 mm) the radiation precisely conforms to the tumor shape, providing complete coverage of the target. 

Throughout the procedure, the neurosurgeon and nursing team will monitor your condition and your comfort and can communicate with you via an audio-video connection

Once the treatment concludes, you will be detached from the Gamma Knife machine and brought to a recovery area, which is in the same room as the prep area.

The physician or the radiation oncologist will remove the frame, provide after-care to the pin sites, and provide appropriate postoperative prescriptions. After the structure is removed, the physician will speak to you about the procedure, discuss the follow-up appointment, and give you instructions on taking your medications.

You might be hungry and thirsty, having not eaten since the night before, so we provide a light snack and beverages such as a sandwich, bagel, banana, yogurt, water, and coffee.

If you came with our transportation services, we would begin coordinating your hospital pickup. This can take anywhere between 5 to 15 minutes. However, if you arrived with a friend or family member, you are free to go home.

If you used our transportation, the nurse is notified when the vehicle arrives and will walk you outside or take you in a wheelchair if you are dizzy from the procedure.

Most patients return home the same day of their Gamma Knife procedure and resume normal activities the following day.

There is a follow up (postoperative evaluation) 1 month after the procedure. Depending on your diagnosis, you might have one, several, or no imaging studies in the months following the procedure to evaluate the effects of the treatment.

For example, if you were diagnosed with multiple brain tumors or malignant brain tumors, you can expect several imaging studies. But if you have a benign brain tumor, you will have an MRI 3 months after your Gamma Knife procedure.

“Because of its extensive use and enormous amount of supportive data generated, the Gamma Knife® is still considered the gold standard.”

-The Journal of Neurosurgery

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FAQ - Frequently Asked Questions

No. Gamma knife is almost always performed on an outpatient basis. Its design allows it to be placed in free-standing centers if specific requirements are met, including lead-lined walls and security protocols. It does not require the resources of an operating room, ER, or acute care hospital. In the rare event that you experience a complication, Larkin Community Hospital is within walking distance of our Neurosurgery Center.

The effects of your treatment will occur over time. Radiation stops or slows the growth of tumors, so the results will be seen over the weeks or months to follow. During this time, your Miami Neuroscience Center doctor will stay in contact to assess your progress, which may include follow-up MRI, CT, or angiography imaging.

The Gamma Knife rays are accurate to within 0.15 mm. The Gamma Knife’s extreme precision allows precise delivery of radiation to deep intracranial targets that would be difficult or impossible to reach with other treatment modalities. This also means there is no substantial effect on healthy tissue outside the target area.

The Gamma Knife treatment can last a few minutes to more than an hour, depending on your pathology. For example, if a patient has one tumor, the gamma knife treatment can take 15 minutes. However, if a patient has multiple metastases, it can take up to several hours. Most of the time, procedures do not take more than two hours.

You can stay awake during the Gamma Knife procedure, but generally, patients fall asleep due to the mild sedation. There are occasions where a patient will be given general anesthesia if they have trouble staying still throughout the procedure. This might include children under the age of 9 or adults that are claustrophobic.

No. Gamma Knife Radiosurgery is a pain-free procedure. Some patients experience minor swelling or discomfort in the areas the four pins are attached to the head, but anesthesia is injected in these areas to reduce the pain.

The number of Gamma Knife treatments you’ll require depends on your diagnosis, but generally, patients only receive one treatment.

No. Gamma Knife surgery does not require cutting or shaving of your hair, nor other intensive physical preparations.

On the day of your treatment, under mild sedation and local anesthetic, you will be fitted with a lightweight stereotactic head frame. Attached by four pins, the structure ensures precise pinpointing of the treatment areas and accurate targeting of Gamma Knife radiation beams.

Some factors affecting the price of a Gamma Knife Procedure include:

  • The number of studies during the diagnosis
  • The number of Gamma Knife procedures needed
  • The number of doses required
  • The number of brain lesions treated
  • The size and shape of the tumor
  • Our contract with your insurance (in-network versus out-of-network)

Contact us today to learn more about our pricing.

At the Miami Neuroscience Center patients have a 90-day global period in which they can be seen by the doctor without additional charges (excluding imaging studies).

Most insurance companies cover Gamma knife procedures as it is seen as a cost-effective and highly successful treatment method for patients with brain cancer and neurological disorders. The treatment will likely be authorized if:

  • You have a life-threatening condition (such as a malignant tumor)
  • It is determined that the neurological disease is located in an area that is difficult to reach.
  • Alternatives such as open surgery or whole brain radiation are inferior, given your pathology.

We have dedicated resources to help you talk with your insurance company to get preauthorization, which means that they will cover your procedure. To see if we accept your insurance, click on the “About” page and scroll down to the table that says “Accepted Insurance Plans.” If you don’t see your insurance plan there or you are confused, you can also call us, email us, or fill out a form on this site with your questions. Also, keep in mind, we have negotiated rates with out-of-network providers and self-pay rates if you believe we’re the right center for your treatment.

Stereotactic Radiosurgery is the use of multiple, highly concentrated, radiation beams to precisely target tumors and other disorders within the body.  Systems such as the Gamma Knife are designed explicitly for treating neurological disorders within the brain and neck. The Gamma Knife can do this using 3-D planning software which allows the physicist to program the specific coordinates of the treatment target.

Gamma Knife is a non-invasive procedure that does not involve cutting or opening the skull. For this reason, there are fewer surgical risks, less discomfort, and quicker recoveries than conventional surgery. It is an outpatient procedure that typically only requires one treatment. If you’re interested in learning more read the sections labeled “How It Works” and “Gamma Rays”.

No. The machine is virtually silent.

The sectors are the metal plates that each contain 24 sources of Cobalt 60. Each sector has a corresponding 72 collimators in the layer beneath it because there are 3 beam sizes to choose from. In total, the Gamma knife machine has 576 collimators.

To see if Gamma Knife® is right for you call us at 786.871.6856 or schedule a consultation today!