The gamma knife, or radio knife, is not just any knife; it is a neurosurgery instrument with extremely high precision. The new machine, called “Icon”, might not fit in a box, but is not so big that it wouldn’t fit in a regular kitchen.
Georges Sinclair, Radio Surgeon and Assistant Senior Physician at the Gamma Knife Unit at Karolinska University Hospital, gives the shiny white machine a pat.
“It’s high-tech neurosurgery,” he says.
Broad area of use
The radio knife is no new invention. Lars Leksell (1907-1986), Professor of Neurosurgery at Karolinska University Hospital, launched it in the middle of the last century. The gamma knife has since been developed into a neurosurgery instrument with a broad area of use. The millionth brain surgery in the world with the technology was recently performed.
“We treat a broad range of diseases, from benign and malignant brain tumours to functional diseases, such as central nerve pain and vascular malformations,” says Georges Sinclair.
Neurosurgery with a radio knife may be a complement or alternative to open surgery where one saws open the skull to be able to operate on the brain with regular surgical instruments.
The technology is based on the breakdown of radioactive cobalt-60, which in turn emits gamma rays. 192 radiation sources are mounted in a hemispheric “helmet”. The patient lies on a table with his or her skull attached to the sphere. In the treatment, all gamma rays are focused on a “target” defined in 3D.
Successful lift into the building
In connection with the move to the new hospital building, the opportunity is taken to replace the old machine that has been used in the cellar of Radiumhemmet since 2010. Just the “radiation unit,” as the visible part of the machine is called, weighs 18.5 tonnes.
“The lift from the lorry went completely according to plan and “Icon” is now installed in the new hospital building. We rolled it in through the opening in the façade that is available for this kind of delivery. The radiation source, which is installed with a charging machine, will be put into place in the next phase, says Erik Östberg, who is responsible for the installation of medical technology equipment for the radiological treatment unit.
The principle is the same for the new machine as for the old.
“The difference is the integrated imaging technology (ConeBeamCT) and that a face mask can be used instead of a frame to attach the patient’s skull so that the radiation ends up exactly where it should go,” says Georges Sinclair.
Enabling even more advanced procedures
In Sweden, the radio knife is only used at Karolinska University Hospital where around 550 operations are performed per year. In the whole world, mainly in the U.S. and Japan, there are around 200 radio knives for treatment and research. The new gamma knife opens new possibilities to develop radio surgery at Karolinska University Hospital, according to Georges Sinclair.
“At the Gamma Knife Unit, we try to be just as visionary as Professor Leksell; we are proud to have developed some innovative neurosurgical procedures, including brain stem surgery. With the new device, we will be able to carry out even more advanced procedures on special tumours, such as meningioma near the optic nerve,” he says.
Today, this kind of brain tumour is treated with a so-called single fraction, a single procedure. With the new radio knife, one can treat the same meningioma several times without damaging the optic nerve.
“Theoretically, with the frame and mask, we could treat other diseases than today. There are very good research opportunities. Our goal is to be the world leaders in our area. For us, it is a way to honour Professor Leksell’s work for clinical and academic excellence,” says Georges Sinclair.