Chief: Dr. Antico Julio

Gamma Knife (Knifeless surgery)
“The delivery of a single high dose of radiation to a small and critically located intracranial volume through the intact skull.” (Steroractic radiosurgery defined by Lars Leksell, 1951).
The Leksell Gamma Knife was developed by Professor Lars Leksell of the Karolinska Institute in Stockholm, Sweden, together with biophysicist Professor Börje Larsson. Leksell found that by administering a single dose of irradiation, it was possible to successfully destroy almost any deep-brain structure without the risk of bleeding or infection. He called this technique “stereotactic radiosurgery” and defined it as the delivery of a single high dose of radiation to a small and critically located intracranial volume through the intact skull. The first Gamma Knife using cobalt-60 sources was constructed and installed in Stockholm in 1967 and expanded successfully the world over. Now, there are more than 180 units installed in health centers.  The benefits of the Leksell Gamma Knife are evident to all parties involved: physicians, patients, hospitals and the community, as it is a unique non-invasive treatment with minimal hospital stay, cost-efficient and outstanding long-term outcomes.

The Principle
The Leksell Gamma Knife shapes the radiation of  201 cobalt-60 sources and focuses it through a collimator helmet to specific target points within the head. Both, this accurate collimation and the sub-millimeter positioning accuracy combine to locate the exact radiation target point. This so-called "Focus Point" is the place where multiple gamma rays converge simultaneously and reach the necessary intensity  to damage the tissue inside the “target volume” at the prescribed dose. The dose of radiation received in the area surrounding the “target” is so small that minimal exposure is ensured to surrounding tissue. Since the Gamma Knife has few moving parts, not active during treatment, it is a more accurate, safe and reliable procedure.

Cost-effectiveness
Gamma Knife surgery compared to conventional open surgery is 20-30% less expensive according to available literature. Consequently, Gamma Knife surgery is more affordable and growingly accepted by patients, physicians and healthcare providers. In many indications, Gamma Knife success rate is higher than that of conventional methods, as, for example, certain arteriovenous malformations and tumors.

Gamma Knife Candidates
Worldwide Gamma Knife Patient Overview as December 1999 (over 130,000 patients)
-Benign tumors (36%): meningiomas, neurinomas, hypophysis tumors, among others.
-Arteriovenous malformations (33%).
-Malignant tumors (29%): metastasic tumors, gliomas, head and neck tumors, among others.
-Functional disorders (10%): trigeminal neuralgia, epilepsy, hypothalamus hamartoma, abnormal movements, intractable pain, among others.
-Ophtalmopathy (1%): uveal melanoma, macular degeneration, thyroid ophtalmopathy.

Clinical Applications
The clinical applications of Leksell Gamma Knife continue to grow. Liiterature indicates that the success rate in metastatic tumors reaches 90% and the total obliteration rate in arteriovenous malformations is approximately 80%. The excellent results and low morbility reported have made Gamma Knife the first therapy option for a growing number of patients. Gamma Knife allows neurosurgeons reach lesions close to critical intracranial structures or high risk patients for conventional surgery.

Gamma Knife Procedure
 Gamma Knife surgery is simple and comprises four basic stages: frame application, MRI for targeting, computer planning and the Gamma Knife treatment itself. This procedure only requires local anesthesia and a mild sedative to prevent any discomfort when the frame is attached. However, children do receive general anesthesia. Patients remain conscious during the whole procedure and may communicate with the surgical team that observe the treatment via video monitors. Typically, patients may resume their daily routine the day after surgery.

Medical Staff
Dr. Antico Julio César
Dr. Artes Carlos  
Dr. Tenca Eduardo

Contact: 5777-3495. E-mail: jantico@fleni.org.ar