Gamma Knife update
The Leksell Gamma Knife uses multiple beams of radiation to perform stereotactic radiosurgery inside the skull without making an incision.
With pinpoint accuracy that spares surrounding tissue, the radiation destroys lesions within the brain, including tumours, arteriovenous malformations and other abnormalities that cause functional disorders, such as trigeminal neuralgia.
Patient in the Leksell Gamma Knife head frame.
Photo courtesy of Elekta
How it works
Diagnostic imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI), is used to locate the target area. The patient wears a head frame to keep the head immobile during the treatment. The Gamma Knife delivers radiation that causes the tumour or lesion to stop growing or to shrink. Patients experience minimal pain during the treatment and they usually go home on the same day.
Gamma Knife units in Canada
Although the Gamma Knife was developed several decades ago it is relatively new to Canada.
| Gamma Knife Unit | Centre | Date Opened |
|---|---|---|
| Winnipeg Centre for Gamma Knife Surgery | Winnipeg Health Sciences Centre | 2003[1] |
| Quebec Gamma Knife Centre | Centre hospitalier universitaire de Sherbrooke (CHUS) | 2004[2] |
| Joey and Toby Tanenbaum Family Gamma Knife Centre | University Health Network, Toronto General Hospital | 2005[3] |
Evidence of clinical effectiveness
Many assessments have examined the evidence for Gamma Knife use and other modes of stereotactic radiosurgery for various conditions. Still lacking are studies that compare outcomes with Gamma Knife radiosurgery to other types of radiosurgery delivery. These include the Novalis® shaped beam radiosurgery system and modified linear accelerators (Linacs) or systems based on linear accelerators, such as the CyberKnife® and XKnife™. Unlike the Gamma Knife, which is used only for intracranial conditions, some of these other systems can be used for radiosurgery elsewhere in the body.
Cost
The Gamma Knife costs about C$5 million. An additional C$1 million to C$2 million is typically needed for set-up costs. Annual operating costs are estimated to be C$1.3 to C$1.5 million.[1,3,4]
The Gamma Knife's cobalt-60 radiation source must be replaced about every five years, at an estimated cost of C$1.1 million (including disposal costs for the old source).[5]
References
[1] Canada's first and only state-of-the-art Gamma Knife unveiled at Winnipeg's Health Sciences Centre [news release]. Winnipeg (MB): Winnipeg Regional Health Authority; 2003. Available: http://www.wrha.mb.ca/howcare/mdesk/news001.php.
[2] Raymond S. Le CHUS et la Faculté de médecine rayonnent grâce au Gamma Knife [news release]. Sherbrooke (QC): Université de Sherbrooke; 2004. Available: http://www.usherbrooke.ca/liaison_vol39/n05/a_knife.html.
[3] Ontario's first Gamma Knife arrives at the Toronto Western Hospital [news release]. Toronto: Toronto Western Hospital / University Health Network; 2005 May 24. Available: http://www.uhn.ca/media/releases/2005/may/gamma_knife_release_may2605.pdf.
[4] Toronto Western Hospital to receive Ontario's first Gamma Knife [news release]. Toronto: Toronto Western Hospital / University Health Network; 2004 Jun 10. Available: http://www.uhn.ca/media/releases/2004/june/twh-neuro-gamma-061004.pdf.
[5] Ohinmaa A. Cost estimation of stereotactic radiosurgery: Application to Alberta. Edmonton (AB): Alberta Heritage Foundation for Medical Research (AHFMR); 2003. Available: http://www.ahfmr.ab.ca/hta/hta-publications/infopapers/ip14.pdf