Neurosurgeon Dr. Robert Spetzler, who helped refine the cardiac standstill procedure, was photographed by National Geographic for a story about how science is redefining life and death.

During the cardiac standstill procedure, a patient’s heartbeat is stopped for about 30 seconds while the surgeon clips off a brain aneurysm.

Read the story and view the photo here: Crossing Over: How Science is Redefining Life and Death