Gamma Knife...

Here is some information about the Gamma Knife - there is a wealth of additional information about it on the internet. It is very similar to the LINAC system that Shands Hospital was going to utilize on Ananda, in that it uses a focused beam of gamma radiation directed precisely to the location of the AVM and aneurysm, with guaranteed accuracy of 0.5mm to an achievable accuracy of 0.15mm...

Florida Hospital Gamma Knife Center

The Gamma Knife® isn't really a knife at all, but radiosurgery - a non-invasive neurosurgical procedure that uses powerful doses of radiation to target and treat diseased brain tissue while leaving surrounding tissue intact. This state-of-the art technology allows physicians to operate on brain lesions often considered inoperable. Gamma Knife treatment offers new hope for patients with brain tumors, vascular malformations and functional disorders.

There is an excellent video on the system here (requires RealPlayer). And I have added additional links to Gamma Knife websites on the links section on the sidebar.

IRSA has a good overview of what is involved with radiosurgery - with some encouraging words:

The usual time to resolution and occlusion in adults is two to three years for AVMs approximately 3cm in size. For reasons as yet unclear, children have a shorter time to obliteration of the AVM after radiosurgery treatment than adults. It is not unusual to see a child's AVM disappear in less than one year and even six months past radiosurgery.

Come on doctors, give us a date...