Image-Guided Surgery; June 1999; Scientific American Magazine; by Grimson, Kikinis, Jolesz, Black; 8 Page(s)

The scene is an operating room. A young woman is about to undergo surgery to remove a brain tumor that is causing almost daily seizures. Elimination of this mass, which has become life-threatening, should be curative, but the operation is perilous. The tumor is pressing against the motor cortex, a strip of tissue that controls voluntary movements. The tumor and cortex look alike to the unaided eye. If some of the tumor is left behind, it will return. Yet if part of the motor cortex is mistakenly excised, the woman could be paralyzed.

The neurosurgeon has agreed to the operation only because he has access to extraordinary tools designed to greatly improve his chances of success. In a corner of the room, he is using one of those innovations now. He is looking at a monitor displaying a three-dimensional computer-generated replica of the patient's head-a model constructed earlier from pictures produced by noninvasive magnetic resonance imaging (MRI).