Stereotactic radiosurgery is a technique to precisely deliver therapeutic radiation to a target within the nervous system while minimising the dose of radiation to adjacent tissues. This reduces the side effects of therapy and allows for repeated treatments in selected cases as well as safer treatment of multiple targets simultaneously e.g. brain metastases.

In contrast to traditional radiotherapy, which aims to halt cell proliferation by impairing the cell's reproductive capacity at the DNA level, radiosurgery is designed to eradicate cells in their original location. This is achieved by directing multiple radiation beams from various angles, each of which is harmless on its own, but collectively they converge on the target to deliver a potent dose to a small area sparing the surrounding tissues.

Technology

The Gamma Knife was the first Stereotactic Radiosurgery system invented by Swedish neurosurgeon Lars Leksell. It has been in clinical use around the world for more than thirty years and the technology has evolved enormously with experience. The London Gamma Knife Centre currently uses the latest evolution called the Gamma Knife Icon. The Gamma Knife has traditionally achieved class-leading sub-millimetirc accuracy using a metal frame secured to the head under local anaesthesia. The GK Icon also allows for the use of a conventional radiotherapy mask without fixation. Treatment of arteriovenous malformations is still carried out with the Leksell frame to allow targeting data from digital subtraction angiography to be incorporated into planning.

Experience

Treatment is typically under local anaesthesia or in cases where a frame is not required no anaesthesia is needed. Although some mild discomfort may be experienced in fitting the frame the treatment itself is painless. You may be able to return to normal activity within 24 hours. For most applications a single treatment is all that is required. Treatment can be interrupted if needed and resumed. The duration of treatment varies according to the volume of the lesion being treated with most lasting 30-90 minutes on the Gamma Knife table.

Safety

Gamma Knife has an excellent safety record and typically compares favourably with surgical treatment for most indications. There have been sporadic reports of malignancy developing in benign tumours after treatment over the past 30 years but this has been scrutinised carefully and the risk continues to be regarded as extremely small. Your treating team will discuss any potential complications with you at your consultation.