Finally: Robot brain surgeons

The working prototype involved the development of a shape-memory alloy needle — that is, an alloy that can remember its original shape and return to it when heated after being deformed — that can operate along a curving path. The robot also needed to be able to operated from inside an MRI machine, which creates a strong magnetic field.

The resultant needle is created from nickel titanium, also known as nitinol, an alloy that has both shape memory and is non-ferromagnetic, making it compatible with MRI machines. The 1.14mm needle operates like a mechanical pencil, consisting of a series of concentric tubes, some of which are curved so as to allow the tip to follow a curved path to the brain.

It is inserted in tiny, millimetre steps that allow the surgeon to track its position by taking MRI scans every step of the way, and its accuracy, the team said, is better than 1.18mm.