The standard treatment for people with metastatic brain tumours – cancer that has spread to the brain from elsewhere in the body – has been radiation of the entire brain (whole-brain radiation). While whole brain radiation helps control tumours, it can also damage healthy tissue and harm a patient’s quality of life by damaging memory and other cognitive functioning. A precise radiation therapy increasingly used at Sunnybrook, called stereotactic radiosurgery (SRS), may make whole-brain radiation – and its side effects – a thing of the past for some patients. Sunnybrook has installed Gamma Knife Icon, the newest and most advanced SRS system, in the Odette Cancer Centre.
With the Icon, our cancer experts will offer precision radiation to a broader group of patients – for instance, to people with as many as 30 brain tumours. And thanks to the Icon's design, patients now wear a mask to minimize movement instead of a head frame fastened to the head with screws.
The Gamma Knife Icon works by focusing hundreds of radiation beams on a single target. Individually each beam is too weak to damage the healthy tissue it crosses on the way to its target, but at the site where they converge, cancerous tissue is destroyed. The Icon's pinpoint precision allows for the safe delivery of effective doses of radiation. The Icon will allow the Odette Cancer Centre to continue replacing whole-brain radiation with targeted radiation procedures for as many as 500 patients annually, a 30-per-cent increase.
The Icon promises to be effective in treating more than brain cancer, however. With its ability to target select areas of the brain, it may eventually be able to address depression, epilepsy, obsessive compulsiveness and essential tremor.