Gamma Knife | doctor search & treatment information

For which diseases is the treatment suitable?

Gamma Knife therapy is a method of radiotherapy. It is used for the treatment of brain tumors or vascular malformations. The treatment is considered to be very safe.

Doctors use Gamma Knife therapy when they are unable to reach the area to be treated using conventional methods. Gamma Knife therapy is also used when patients are not stable enough for longer operations.

Specialists in Gamma Knife therapy are radio-oncologists, neuro-oncologists or radiosurgeons.

Gamma Knife therapy is used for the following diseases:

• Brain tumors and brain metastases

Radiosurgical treatment is possible for benign and malignant tumors. The gamma radiation destroys the DNA (genetic material) in the tumor cells. The aim is not to remove the tumor, but to stop it from growing. The volume of the tumor decreases over time after irradiation.

• Epiphyseal tumors

The pineal gland is a gland at the base of the brain that plays an important role in hormone regulation. Tumors of the epiphysis lead to metabolic disorders and reduced or increased hormone production. Shrinking such tumors is possible with Gamma Knife therapy.

• Schwannomas

Schwannomas are benign growths that affect the auditory and vestibular nerves. Pressure on the nerve causes dizziness, hearing loss or tinnitus. The face or facial muscles can also be affected. With Gamma Knife therapy, doctors can successfully stop the spread of the disease.

• Malformations of the cerebral vessels

Cerebrovascular diseases are abnormal formations of vessels (arteries and veins) in the brain. Additional connections between arteries and veins, for example, mean that smaller vessels do not receive enough blood. Gamma Knife therapy destroys such vascular connections and restores normal blood flow.

• Neuralgia

Neuralgia of the trigeminal nerve (trigeminal neuralgia) can affect one or both halves of the face. Those affected suffer from stabbing pain in the forehead, cheeks or jaw area. Patients experience relief within a few days to months as a result of radiotherapy.

Radiosurgical treatment with the Gamma Knife is carried out on an outpatient basis or as part of a short inpatient stay @ ATRPhoto /AdobeStock

Treatment procedure

Before the radiotherapy takes place, doctors carry out detailed examinations of the tumor or the malformed vessels. Only then can they plan the radiosurgical treatment.

1. Doctors use computer tomography (CT) or magnetic resonance imaging (MRI) for the preliminary examinations. If the doctors use a contrast agent during the examination, they inject it via a venous catheter.
2. Radio-oncologists can calculate the necessary radiation dose from the results of the examination. They determine the area of the brain to be treated and the alignment of the individual beams.
3. These steps are computer-controlled. The doctor transmits the data directly to the radiation unit. The patient lies down during the radiation treatment. They move into the radiation unit on a couch or bed. The head frame then connects to the device.
4. To stabilize the head during treatment and focus the individual beams precisely, the oncologist attaches a lightweight, stereotactic frame. Doctors attach this using four pins under local anesthesia. General anesthesia is not usually necessary for the treatment, but patients are given a mild sedative if they wish.

The duration of treatment varies between one and five hours. If the treatment lasts longer, the doctor will give the patient infusions to stabilize the circulation.

During the radiation treatment, it is possible for the patient to communicate with the doctors via a microphone. The treatment is silent and painless.

Doctors painlessly attach a light frame to the skull under local anesthesia @ Monkey Business /AdobeStock

Side effects and risks of Gamma Knife therapy

As Gamma Knife therapy is a non-invasive treatment method, the risks are lower than with open brain surgery.

Side effects that occur directly after treatment are usually short-lived and disappear after a few days to weeks.

If headaches, nausea or vomiting occur directly after radiation, the doctor will treat the symptoms with medication.

The area of the head that was connected to the frame may bleed slightly. The patient can eat and drink immediately after treatment.

Common complaints include:

• Nausea or vomiting
• headache
• Tiredness
• An itchy feeling on the scalp
• Swelling of the irradiated brain tissue
• Swelling or redness of the scalp
• Minor hair loss in the irradiated areas
• In very rare cases, neurological symptoms are recorded as a late consequence.

Prognosis of Gamma Knife therapy

The prognosis for Gamma Knife irradiation depends on the underlying disease and the patient's general state of health.

As a rule, doctors achieve good results with Gamma Knife therapy:

• The volume of benign tumors shrinks within one to two years.
• Malignant tumors often shrink quickly.
• The closure of abnormal brain vessels also takes up to two years or longer.
• Pain treatment for neuralgia shows results within a few months.

Conclusion

Gamma Knife therapy is a safe and precise method of radiotherapy. Doctors are currently using it for brain tumors. Compared to open brain surgery, the risks are low.

The radiation itself is controlled by a computer. The latest devices are called Cyberknife and are based on robot technology. Doctors use them to irradiate tumors all over the body. There are now more than ten of these devices in oncology centers in Germany.

It is important that the patient attends regular check-ups so that the doctor can monitor the success of the treatment and the progression of the disease.