A Guide to CyberKnife and Gamma Knife Radiosurgery in Turkey

What is Stereotactic Radiosurgery?

Stereotactic radiosurgery (SRS) is a highly advanced and precise form of radiation therapy used to treat tumors and other abnormalities, typically in the brain and other parts of the body. Despite the name, radiosurgery is not a surgical procedure in the traditional sense. There are no incisions or scalpels involved. Instead, it uses many hundreds of highly focused, computer-guided beams of radiation that converge with pinpoint accuracy on a specific target.

The goal of radiosurgery is to deliver a very high, ablative dose of radiation to the tumor in a single session (or a small number of sessions), with the intention of destroying the target cells while causing little to no damage to the surrounding healthy tissue. This precision is what distinguishes SRS from conventional radiation therapy, which uses lower doses delivered over many weeks. In Turkey, specialized oncology centers are equipped with state-of-the-art radiosurgery platforms like Gamma Knife® and CyberKnife®, which represent the forefront of non-invasive cancer treatment.

The Radiosurgery Multidisciplinary Team

The planning and execution of stereotactic radiosurgery is a highly technical process that requires the close collaboration of a specialized multidisciplinary team.

• Radiation Oncologist: A physician specializing in radiation therapy who leads the team. They determine if a patient is a suitable candidate for SRS and prescribe the precise radiation dose.
• Neurosurgeon: For treatments involving the brain, a neurosurgeon works alongside the radiation oncologist to define the target and critical structures. Their deep knowledge of neuroanatomy is essential.
• Medical Physicist: This expert is responsible for all technical aspects of the treatment plan. They perform complex calculations to ensure the radiation dose is delivered accurately and safely, and they are in charge of the quality assurance of the machines.
• Dosimetrist: Working with the physicist and oncologist, the dosimetrist uses sophisticated software to map out the radiation beams and create the final treatment plan.
• Radiation Therapists: These are the skilled technologists who operate the radiosurgery machine and position the patient for treatment.

Gamma Knife® Radiosurgery

Gamma Knife radiosurgery is considered a gold standard for treating small to medium-sized tumors and other abnormalities within the brain. It is known for its extreme precision.

• How it Works: The Gamma Knife system uses 192 or 201 individual beams of cobalt-60 radiation that are all aimed at a single, precise focal point. Individually, each beam is too weak to cause significant damage to the tissue it passes through. However, at the point where all the beams converge—the tumor—the combined energy is extremely high and is able to destroy the target cells.
• The Procedure: The defining feature of the Gamma Knife procedure is the use of a stereotactic head frame. This is a lightweight frame that is attached to the patient’s head with pins under local anesthesia on the morning of the treatment. This frame provides absolute immobilization, ensuring that the target inside the brain does not move by even a millimeter during treatment. The patient, with the frame attached, lies on a treatment couch that moves into the Gamma Knife machine. The treatment is delivered in a single session, after which the frame is removed.

Gamma Knife technology is exclusively used for treating conditions within the head and neck.

CyberKnife® Radiosurgery

The CyberKnife system is a more recent innovation in radiosurgery that offers greater flexibility, allowing for the treatment of tumors not only in the brain but throughout the body.

• How it Works: The CyberKnife system consists of a compact linear accelerator (the machine that generates the radiation) mounted on a highly maneuverable robotic arm. This robotic arm can move and rotate around the patient, aiming the radiation beam from hundreds of different angles.
• The Procedure: The key advantage of CyberKnife is that it is a “frameless” system. Instead of a rigid head frame, it uses advanced real-time imaging and a sophisticated tumor-tracking system. X-ray cameras and computer software monitor the patient’s position and can even track the tumor’s movement with breathing. The robotic arm automatically adjusts to these movements, ensuring the radiation beam remains locked onto the target at all times. Because of this flexibility, treatment may be delivered in a single session (SRS) or, more commonly for body tumors, divided into two to five sessions, a process called stereotactic body radiation therapy (SBRT).

Conditions Treated with Radiosurgery in Turkey

Radiosurgery is a powerful tool used to treat a variety of both cancerous and non-cancerous conditions.

• Brain Tumors: This is the most common application. It is used to treat brain metastases (cancer that has spread to the brain from elsewhere), benign tumors like meningiomas and acoustic neuromas (vestibular schwannomas), and some primary malignant brain tumors.
• Body Tumors (SBRT): The CyberKnife system allows for the treatment of small, well-defined tumors in other parts of the body, including:
  • Primary lung cancer or lung metastases
  • Liver cancer or liver metastases
  • Pancreatic cancer
  • Prostate cancer
  • Spinal tumors
• Other Conditions: SRS can also be used to treat non-cancerous conditions such as arteriovenous malformations (AVMs), which are abnormal tangles of blood vessels in the brain, and functional disorders like trigeminal neuralgia.

The Patient Experience: What to Expect

For the patient, a radiosurgery procedure is typically an outpatient experience.

1. Planning: Days or weeks before the treatment, the patient will have high-resolution imaging scans (usually an MRI and/or CT scan) which are used to create the detailed 3D treatment plan.
2. Treatment Day: On the day of the procedure, the patient arrives at the hospital. For Gamma Knife, the head frame is fitted. For CyberKnife, a custom mask or body mold may be used for comfort and positioning.
3. The Treatment: The patient lies on the treatment couch. The session itself is painless. The patient is awake and can often listen to music. The total time in the treatment room can range from 30 minutes to over an hour, depending on the complexity of the plan.
4. After Treatment: After the session is complete, the head frame (if used) is removed. The patient is monitored for a short period and then is typically able to go home the same day. Most people can return to their normal, non-strenuous activities within a day or two.

Frequently Asked Questions

1. Is stereotactic radiosurgery a type of surgery?
No. Despite the name, it is a non-invasive radiation therapy technique. There are no incisions, no blood loss, and no surgical instruments entering the body. The term “radiosurgery” is used because the effect of the single high dose of radiation is so precise and destructive to the target tissue that it is like removing it with a surgical knife.

2. What is the main difference between Gamma Knife and CyberKnife?
The main differences relate to what they can treat and how they achieve precision. Gamma Knife is exclusively for treating conditions in the brain and neck, and it uses a rigid head frame for immobilization. CyberKnife can treat tumors anywhere in the body, and it uses a frameless system with advanced robotics and real-time image guidance to track the tumor.

3. Is the treatment painful?
No, the radiation itself is painless and cannot be felt. For Gamma Knife treatment, there is some discomfort during the fitting of the head frame, which is done under local anesthesia. During the treatment session itself, the patient simply lies still.

4. Who is a good candidate for radiosurgery?
Radiosurgery is generally best suited for treating small, well-defined tumors. It is not appropriate for very large tumors or for disease that has spread extensively. The decision of whether a patient is a good candidate is made by the multidisciplinary team after a thorough review of their specific case, tumor characteristics, and imaging scans.

5. How many treatment sessions are required?
This depends on the technology used and the location of the tumor. Gamma Knife treatment for the brain is almost always delivered in a single session. CyberKnife treatment can be a single session (SRS) or can be fractionated, meaning the total dose is divided and delivered over two to five sessions (SBRT).

6. What are the potential side effects?
Because radiosurgery is so highly focused, it has fewer side effects than traditional radiation therapy. Side effects are generally mild and related to the specific area being treated. For brain treatments, this can include temporary fatigue, headache, or swelling (edema) around the treatment site, which can be managed with medication.

7. How quickly does radiosurgery work?
The effects of radiosurgery are not immediate. The high dose of radiation damages the DNA of the tumor cells, causing them to stop growing and to gradually shrink over a period of weeks, months, or even years. The medical team will monitor the tumor’s response with follow-up imaging scans.