What is Gamma Knife Radiosurgery ?
What is Gamma Knife Radiosurgery ?
The Gamma Knife is actually not a knife at all. It is a revolutionary tool available for the non-invasive neurosurgical treatment of specific indications of the brain. Gamma Knife radiosurgery is a non-invasive method used for the treatment of arteriovenous malformations (AVMs), benign and malignant tumours and functional disorders of the brain. It does not involve traditional surgical incisions and thus devoid of post-operative complications with virtually no risk of mortality. There is no lengthy recuperation and most patients return to work within 2 to 3 days.
Who is Gamma Knife's manufacturer ?
The instrument, officially called the Leksell Gamma Knife(approx.US$3-4 million including site preparation), is manufactured by Elekta Instruments Inc. of Stockholm. The Gamma Knife was developed in 1950 by a Swedish neurosurgeon, Dr. Lars Leksell of the Karolinska Institute in Stockholm, aided by a physicist, Dr. Borje Larsson of the Gustaf Werner Institute at the University of Uppsala in Sweden. Elekta was founded in 1972 by the late Lars Leksell, Professor of Neurosurgery at the Karolinska Institute in Stockholm. The first Gamma Knife prototype was installed at the Karolinska Hospital in 1968, but the international launch of the Leksell Gamma Knife did not start until 1987 because its application had to await brain imaging techniques like the CT scan and MRI that could tell surgeons exactly where to aim the intersection of the radiation beams. . Elekta has 250 employees (including subsidiaries). 98 Million in revenue for 1994/95 fiscal year.
How does it work ?
The 201 narrowly focused beams of gamma rays destroy only the tissue where the beams meet.
The principle of Gamma Knife surgery is simple. The $3.5 million machine replaces the surgeon's scalpel with a single, high dose of gamma radiation emitted by a cobalt-60 source(The Cobalt source has to be replaced every 5-10 years). The patient wears a helmet resembling a beauty salon hair dryer. The helmet has 201 separate small round holes in it that aim the ionizing radiation so that 201 narrow beams of gamma rays are all aimed at a single tiny targeted lesion. The tissue being treated with an accuracy of better than 0.3mm, thus receives a very strong dose of radiation without harming anything along the way. This 'crossfiring' results in destruction of the lesion with sparing the adjacent normal brain tissue around it from the highest doses of radiation.
What is the Gamma Knife Procedure?
Gamma Knife treatment is straightforward and consists of four basic phases - frame fixation, imaging, treatment planning and the treatment itself.
What type of disorders can be treated by the Gamma Knife ?
Arteriovenous malformations, benign and malignant tumours of the brain can be treated by the Gamma Knife. The benign tumours commonly treated include acoustic neuromas, skullbase meningiomas and pituitary tumours. Among the commonly treated malignant tumours are cerebral metastases and selected cases of malignant gliomas. The majority of tumours treated are below 4 cm in diameter. Now, in collaboration with radiologists, neurosurgeons experienced in stereotactic radiosurgery are cautiously beginning to extend its use: to quell intractable facial pain in patients with trigeminal neuralgia, to relieve chronic cancer pain, to obliterate abnormal areas of brain tissue that give rise to uncontrollable and to treat psychoneurosis, Parkinson's disease and other movement disorders. The Gamma Knife has also been used to treat cancers of the eye and benign tumors of the pituitary gland at the base of the brain.
How long does it take for a Gamma Knife treatment
The procedure is usually performed under local anesthesia with mild sedation,takes just 15 to 40 minutes, depending on the size of the area needing treatment. If necessary, the beams can be refocused and the procedure repeated until the entire diseased area is treated. If there are multiple tumors or if the tumor spreads to another area, radiosurgery can be repeated again and again. Free of surgical complications like infection hemorrhage and leakage of spinal fluid, radiosurgery has proved very appealing to the candidates for brain surgery who have so far been given this option.
How long does it take for the results of Gamma Knife to be apparent?
Since the effect of Gamma Knife surgery is gradual, it may take several weeks to months before the effect of treatment becomes apparent. As a general guildline, malignant tumours show improvement, both clinically and radiologiclly, much more quickly (usually in weeks) than the benign tumours (usually in months). Arteriovenous malformations may require one to two years for the abnormal blood vessels to be completely obliterated.
What are the side effects of Gamma Knife treatment?
During a Gamma Knife procedure the beams of Gamma radiation are widely dispersed over the surface of the patient's head. Each of the beams produces a very small dose of radiation. A very strong dose of radiation occurs only at the target, where the 201 beams intersect. The fact that the irradiation from the Gamma Knife can be very precisely targeted to the treatment lesion means that only a very small amount of radiation is received by the normal brain tissue and adjacent structures. However, a small risk of adverse radiation effects (2 to 4%). This is usually in the form of swelling of the tumour and surrounding brain. Most of the effects are transient and can be treated effectively with medications. There are few side effects such as hair loss.
Is Gamma Knife treatment used elsewhere in the world?
At present there are more than 75 sites worldwide (over 40 in the United States and Europe). Over 37,000 patients have received the treatment.
What are the benefits of Gamma Knife treatment ?
The main advantage of the Gamma Knife treatment is that it is non-invasive , painless, bloodless. Patients do not feel pain during the procedure, which is performed with local anesthesia and mild sedation. Because no incision is made in the scalp or skull, complication such as infection, hemorrhaging and spinal fluid leakage do not occur. No lengthy recuperation is required and the patient may resume his normal occupation and life style within a few days. The Gamma Knife is particularly suited for lesion in the deep and critically located areas of the brain where traditional surgery carries a high risk. It is also suited for old and infirmed where again traditional surgery involves a higher risk, In many situations, Gamma Knife surgery and traditional surgery are combined to give the best clinical results. Since its use in 1968, the Gamma Knife has proven its efficacy and safety as a surgical tool in over 37,000 procedures worldwide.
What is the difference the Gamma Knife and a LINAC(X-Knife) ?
Gamma Knife Radiosurgery vs. LINAC Radiosurgery
What is the Proton Beam Unit ?
The Proton Beam Unit was founded in 1962 and has the largest experience with stereotactic radiosurgery of any center in the United States. Proton beam offers certain theoretical advantages over other modalities of stereotactic radiosurgery (i.e. Gamma Knife and linear accelerators)because it makes use of the quantum wave properites of protons to reduces doses to surrounding tissue beyond the target to a theoretical minimum of zero. In practice, the proton facility offers advantages for the treatment of unusually shaped brain tumors and arteriovenous malformations. The homogeneous doses delivered also makes fractionated therapy possible. Proton beam radiosurgery also has the ability to treat tumors outside of the cranial cavity. These properties make it the ideal post-resection therapy for many chordomas and certain chondrosarchomas of the spine and skull base as well as an excellent mode of therapy for many other types of tumors.